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Malta M, AlMutiri R, Martin CS, Srour M. Holoprosencephaly: Review of Embryology, Clinical Phenotypes, Etiology and Management. CHILDREN 2023; 10:children10040647. [PMID: 37189898 DOI: 10.3390/children10040647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/21/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023]
Abstract
Holoprosencephaly (HPE) is the most common malformation of the prosencephalon in humans. It is characterized by a continuum of structural brain anomalies resulting from the failure of midline cleavage of the prosencephalon. The three classic subtypes of HPE are alobar, semilobar and lobar, although a few additional categories have been added to this original classification. The severity of the clinical phenotype is broad and usually mirrors the radiologic and associated facial features. The etiology of HPE includes both environmental and genetic factors. Disruption of sonic hedgehog (SHH) signaling is the main pathophysiologic mechanism underlying HPE. Aneuploidies, chromosomal copy number variants and monogenic disorders are identified in a large proportion of HPE patients. Despite the high postnatal mortality and the invariable presence of developmental delay, recent advances in diagnostic methods and improvements in patient management over the years have helped to increase survival rates. In this review, we provide an overview of the current knowledge related to HPE, and discuss the classification, clinical features, genetic and environmental etiologies and management.
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Barratt KS, Drover KA, Thomas ZM, Arkell RM. Patterning of the antero-ventral mammalian brain: Lessons from holoprosencephaly comparative biology in man and mouse. WIREs Mech Dis 2022; 14:e1552. [PMID: 35137563 DOI: 10.1002/wsbm.1552] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 11/30/2021] [Accepted: 12/21/2021] [Indexed: 12/13/2022]
Abstract
Adult form and function are dependent upon the activity of specialized signaling centers that act early in development at the embryonic midline. These centers instruct the surrounding cells to adopt a positional fate and to form the patterned structures of the phylotypic embryo. Abnormalities in these processes have devastating consequences for the individual, as exemplified by holoprosencephaly in which anterior midline development fails, leading to structural defects of the brain and/or face. In the 25 years since the first association between human holoprosencephaly and the sonic hedgehog gene, a combination of human and animal genetic studies have enhanced our understanding of the genetic and embryonic causation of this congenital defect. Comparative biology has extended the holoprosencephaly network via the inclusion of gene mutations from multiple signaling pathways known to be required for anterior midline formation. It has also clarified aspects of holoprosencephaly causation, showing that it arises when a deleterious variant is present within a permissive genome, and that environmental factors, as well as embryonic stochasticity, influence the phenotypic outcome of the variant. More than two decades of research can now be distilled into a framework of embryonic and genetic causation. This framework means we are poised to move beyond our current understanding of variants in signaling pathway molecules. The challenges now at the forefront of holoprosencephaly research include deciphering how the mutation of genes involved in basic cell processes can also cause holoprosencephaly, determining the important constituents of the holoprosencephaly permissive genome, and identifying environmental compounds that promote holoprosencephaly. This article is categorized under: Congenital Diseases > Stem Cells and Development Congenital Diseases > Genetics/Genomics/Epigenetics Congenital Diseases > Molecular and Cellular Physiology Congenital Diseases > Environmental Factors.
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Affiliation(s)
- Kristen S Barratt
- John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Kyle A Drover
- John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Zoe M Thomas
- John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Ruth M Arkell
- John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia
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Loo CKC, Pearen MA, Ramm GA. The Role of Sonic Hedgehog in Human Holoprosencephaly and Short-Rib Polydactyly Syndromes. Int J Mol Sci 2021; 22:ijms22189854. [PMID: 34576017 PMCID: PMC8468456 DOI: 10.3390/ijms22189854] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/03/2021] [Accepted: 09/09/2021] [Indexed: 12/18/2022] Open
Abstract
The Hedgehog (HH) signalling pathway is one of the major pathways controlling cell differentiation and proliferation during human development. This pathway is complex, with HH function influenced by inhibitors, promotors, interactions with other signalling pathways, and non-genetic and cellular factors. Many aspects of this pathway are not yet clarified. The main features of Sonic Hedgehog (SHH) signalling are discussed in relation to its function in human development. The possible role of SHH will be considered using examples of holoprosencephaly and short-rib polydactyly (SRP) syndromes. In these syndromes, there is wide variability in phenotype even with the same genetic mutation, so that other factors must influence the outcome. SHH mutations were the first identified genetic causes of holoprosencephaly, but many other genes and environmental factors can cause malformations in the holoprosencephaly spectrum. Many patients with SRP have genetic defects affecting primary cilia, structures found on most mammalian cells which are thought to be necessary for canonical HH signal transduction. Although SHH signalling is affected in both these genetic conditions, there is little overlap in phenotype. Possible explanations will be canvassed, using data from published human and animal studies. Implications for the understanding of SHH signalling in humans will be discussed.
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Affiliation(s)
- Christine K. C. Loo
- South Eastern Area Laboratory Services, Department of Anatomical Pathology, NSW Health Pathology, Prince of Wales Hospital, Sydney, NSW 2031, Australia
- Correspondence: ; Tel.: +61-2-93829015
| | - Michael A. Pearen
- Hepatic Fibrosis Group, Department of Cell and Molecular Biology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia; (M.A.P.); (G.A.R.)
| | - Grant A. Ramm
- Hepatic Fibrosis Group, Department of Cell and Molecular Biology, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia; (M.A.P.); (G.A.R.)
- Faculty of Medicine, The University of Queensland, Brisbane, QLD 4006, Australia
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Stadler JT, Wadsack C, Marsche G. Fetal High-Density Lipoproteins: Current Knowledge on Particle Metabolism, Composition and Function in Health and Disease. Biomedicines 2021; 9:biomedicines9040349. [PMID: 33808220 PMCID: PMC8067099 DOI: 10.3390/biomedicines9040349] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/24/2021] [Accepted: 03/25/2021] [Indexed: 12/20/2022] Open
Abstract
Cholesterol and other lipids carried by lipoproteins play an indispensable role in fetal development. Recent evidence suggests that maternally derived high-density lipoprotein (HDL) differs from fetal HDL with respect to its proteome, size, and function. Compared to the HDL of adults, fetal HDL is the major carrier of cholesterol and has a unique composition that implies other physiological functions. Fetal HDL is enriched in apolipoprotein E, which binds with high affinity to the low-density lipoprotein receptor. Thus, it appears that a primary function of fetal HDL is the transport of cholesterol to tissues as is accomplished by low-density lipoproteins in adults. The fetal HDL-associated bioactive sphingolipid sphingosine-1-phosphate shows strong vasoprotective effects at the fetoplacental vasculature. Moreover, lipoprotein-associated phospholipase A2 carried by fetal-HDL exerts anti-oxidative and athero-protective functions on the fetoplacental endothelium. Notably, the mass and activity of HDL-associated paraoxonase 1 are about 5-fold lower in the fetus, accompanied by an attenuation of anti-oxidative activity of fetal HDL. Cholesteryl ester transfer protein activity is reduced in fetal circulation despite similar amounts of the enzyme in maternal and fetal serum. This review summarizes the current knowledge on fetal HDL as a potential vasoprotective lipoprotein during fetal development. We also provide an overview of whether and how the protective functionalities of HDL are impaired in pregnancy-related syndromes such as pre-eclampsia or gestational diabetes mellitus.
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Affiliation(s)
- Julia T. Stadler
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
- Correspondence: (J.T.S.); (G.M.); Tel.: +43-316-385-74115 (J.T.S.); +43-316-385-74128 (G.M.)
| | - Christian Wadsack
- Department of Obstetrics and Gynecology, Medical University of Graz, Auenbruggerplatz 14, 8036 Graz, Austria;
| | - Gunther Marsche
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Universitätsplatz 4, 8010 Graz, Austria
- Correspondence: (J.T.S.); (G.M.); Tel.: +43-316-385-74115 (J.T.S.); +43-316-385-74128 (G.M.)
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Temple SEL, Sachdev R, Ellaway C. Familial DHCR7 genotype presenting as a very mild form of Smith-Lemli-Opitz syndrome and lethal holoprosencephaly. JIMD Rep 2020; 56:3-8. [PMID: 33204589 PMCID: PMC7653247 DOI: 10.1002/jmd2.12155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 11/09/2022] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive metabolic disorder caused by variants in the DHCR7 gene. In cholesterol biosynthesis, 7-dehydrocholesterol (7-DHC) is converted to cholesterol by the enzyme 7-DHC reductase, which is encoded by the gene DHCR7. Thus, an elevated 7-DHC is indicative of SLOS. Characteristically SLOS is usually associated with congenital anomalies, dysmorphisms, and moderate to severe neurodevelopmental delay. However, there are rare descriptions of individuals with milder phenotypes. We report a mild case of SLOS presenting with short stature, cleft palate, imperforate anus, and mild language delay with subtle dysmorphic features. 7-DHC was not elevated at 1 year of age and SLOS considered excluded at this time. The parents had two pregnancies with holoprosencephaly. Whole exome sequencing of one of the fetuses identified compound heterozygous pathogenic variants in the DHCR7 gene (c.964-1G>C (p.?) and c.1039G>A (p.Gly347Ser) causative of SLOS. The proband with a mild form of SLOS was also found to have the same DHCR7 variants as the fetus and repeat testing of 7-DHC at 4 years of age was elevated, in keeping with SLOS. This case is the first to describe a wide intrafamilial phenotypic spectrum of SLOS as a result of the same DHCR7 genotype. This case also supports the findings of others that a normal or near normal development should not exclude SLOS. As demonstrated in this case exclusion of a metabolic diagnosis because of a negative biochemical marker such as 7-DHC is not absolute and if clinical suspicion remains genomic sequencing is warranted.
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Affiliation(s)
- Suzanna E. L. Temple
- Centre for Clinical GeneticsSydney Children's HospitalRandwickNew South WalesAustralia
| | - Rani Sachdev
- Centre for Clinical GeneticsSydney Children's HospitalRandwickNew South WalesAustralia
| | - Carolyn Ellaway
- Centre for Clinical GeneticsSydney Children's HospitalRandwickNew South WalesAustralia
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Zhou H, Gong Y, Wu Q, Ye X, Yu B, Lu C, Jiang W, Ye J, Fu Z. Rare Diseases Related with Lipoprotein Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:171-188. [PMID: 32705600 DOI: 10.1007/978-981-15-6082-8_11] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Rare diseases are gathering increasing attention in last few years, not only for its effects on innovation scientific research, but also for its propounding influence on common diseases. One of the most famous milestones made by Michael Brown and Joseph Goldstein in metabolism field is the discovery of the defective gene in familial hypercholesterolemia, a rare human genetic disease manifested with extreme high level of serum cholesterol (Goldstein JL, Brown MS, Proc Natl Acad Sci USA 70:2804-2808, 1973; Brown MS, Dana SE, Goldstein JL, J Biol Chem 249:789-796, 1974). Follow-up work including decoding the gene function, mapping-related pathways, and screening therapeutic targets are all based on the primary finding (Goldstein JL, Brown MS Arterioscler Thromb Vasc Biol 29:431-438, 2009). A series of succession win the two brilliant scientists the 1985 Nobel Prize, and bring about statins widely used for lipid management and decreasing cardiovascular disease risks. Translating the clinical extreme phenotypes into laboratory bench work has turned out to be the first important step in the paradigm conducting translational and precise medical research. Here we review the main categories of rare disorders related with lipoprotein metabolism, aiming to strengthen the notion that human rare inheritable genetic diseases would be the window to know ourselves better, to treat someone more efficiently, and to lead a healthy life longer. Few rare diseases related with lipoprotein metabolism were clustered into six sections based on changes in lipid profile, namely, hyper- or hypocholesterolemia, hypo- or hyperalphalipoproteinemia, abetalipoproteinemia, hypobetalipoproteinemia, and sphingolipid metabolism diseases. Each section consists of a brief introduction, followed by a summary of well-known disease-causing genes in one table, and supplemented with one or two diseases as example for detailed description. Here we aimed to raise more attention on rare lipoprotein metabolism diseases, calling for more work from basic research and clinical trials.
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Affiliation(s)
- Hongwen Zhou
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China.
| | - Yingyun Gong
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Qinyi Wu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xuan Ye
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Baowen Yu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Chenyan Lu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Wanzi Jiang
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jingya Ye
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhenzhen Fu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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Schoner K, Witsch-Baumgartner M, Behunova J, Petrovic R, Bald R, Kircher SG, Ramaswamy A, Kluge B, Meyer-Wittkopf M, Schmitz R, Fritz B, Zschocke J, Laccone F, Rehder H. Smith-Lemli-Opitz syndrome - Fetal phenotypes with special reference to the syndrome-specific internal malformation pattern. Birth Defects Res 2019; 112:175-185. [PMID: 31840946 PMCID: PMC7432161 DOI: 10.1002/bdr2.1620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 01/31/2023]
Abstract
Background Autosomal‐recessive SLOS is caused by mutations in the DHCR7 gene. It is defined as a highly variable complex of microcephaly with intellectual disability, characteristic facies, hypospadias, and polysyndactyly. Syndrome diagnosis is often missed at prenatal ultrasound and fetal autopsy Methods We performed autopsies and DHCR7 gene analyses in eight fetuses suspected of having SLOS and measured cholesterol values in long‐term formalin‐fixed tissues of an additional museum exhibit Results Five of the nine fetuses presented classical features of SLOS, including four cases with atrial/atrioventricular septal defects and renal anomalies, and one with additional bilateral renal agenesis and a Dandy‐Walker cyst. These cases allowed for diagnosis at autopsy and subsequent SLOS diagnosis in two siblings. Two fetuses were mildly affected and two fetuses showed additional holoprosencephaly. These four cases and the exhibit had escaped diagnosis at autopsy. The case with bilateral renal agenesis presented a novel combination of a null allele and a putative C‐terminus missense mutation in the DHCR7 gene Conclusions In view of the discrepancy between the prevalence of SLOS among newborns and the carrier frequency of a heterozygous DHCR7 gene mutation, the syndrome‐specific internal malformation pattern may be helpful not to miss SLOS diagnosis in fetuses at prenatal ultrasound and fetal autopsy
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Affiliation(s)
- Katharina Schoner
- Institute of Pathology, Philipps-University Marburg, Marburg, Germany
| | | | - Jana Behunova
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | - Robert Petrovic
- Institute of Medical Biology, Comenius University Bratislava, Bratislava, Slovakia
| | - Rainer Bald
- Clinic of Gynecology and Obstetrics, Klinikum Leverkusen, Leverkusen, Germany
| | - Susanne G Kircher
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | - Annette Ramaswamy
- Institute of Pathology, Philipps-University Marburg, Marburg, Germany
| | - Britta Kluge
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | | | - Ralf Schmitz
- Clinic of Gynecology and Obstetrics, University Clinic Muenster, Münster, Germany
| | - Barbara Fritz
- Institute of Human Genetics, Philipps-University Marburg, Marburg, Germany
| | - Johannes Zschocke
- Institute of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Franco Laccone
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | - Helga Rehder
- Institute of Pathology, Philipps-University Marburg, Marburg, Germany.,Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
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Calloni SF, Caschera L, Triulzi FM. Disorders of Ventral Induction/Spectrum of Holoprosencephaly. Neuroimaging Clin N Am 2019; 29:411-421. [DOI: 10.1016/j.nic.2019.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ohuchi H, Sato K, Habuta M, Fujita H, Bando T. Congenital eye anomalies: More mosaic than thought? Congenit Anom (Kyoto) 2019; 59:56-73. [PMID: 30039880 DOI: 10.1111/cga.12304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 07/16/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022]
Abstract
The eye is a sensory organ that primarily captures light and provides the sense of sight, as well as delivering non-visual light information involving biological rhythms and neurophysiological activities to the brain. Since the early 1990s, rapid advances in molecular biology have enabled the identification of developmental genes, genes responsible for human congenital diseases, and relevant genes of mutant animals with various anomalies. In this review, we first look at the development of the eye, and we highlight seminal reports regarding archetypal gene defects underlying three developmental ocular disorders in humans: (1) holoprosencephaly (HPE), with cyclopia being exhibited in the most severe cases; (2) microphthalmia, anophthalmia, and coloboma (MAC) phenotypes; and (3) anterior segment dysgenesis (ASDG), known as Peters anomaly and its related disorders. The recently developed methods, such as next-generation sequencing and genome editing techniques, have aided the discovery of gene mutations in congenital eye diseases and gene functions in normal eye development. Finally, we discuss Pax6-genome edited mosaic eyes and propose that somatic mosaicism in developmental gene mutations should be considered a causal factor for variable phenotypes, sporadic cases, and de novo mutations in human developmental disorders.
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Affiliation(s)
- Hideyo Ohuchi
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Keita Sato
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Munenori Habuta
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hirofumi Fujita
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Tetsuya Bando
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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Solomon BD, Retterer K, Juusola J. Holoprosencephaly: A clinical genomics perspective. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2018; 178:194-197. [PMID: 29749690 DOI: 10.1002/ajmg.c.31613] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 04/03/2018] [Accepted: 04/04/2018] [Indexed: 12/17/2023]
Abstract
New and rapidly evolving technologies have dramatically impacted the practice of clinical genetics as well as broader areas of medicine. To illustrate this trend from the perspective of a clinical molecular laboratory, we briefly summarize our general experience conducting exome testing for patients with holoprosencephaly (HPE). Though these cases are not representative of HPE more generally (i.e., cases undergoing exome sequencing represent a skewed sample), results include a 22% positive rate from exome testing. Of interest, 29% of reported results involved genes not considered to be classic HPE genes, indicating more evidence that HPE may fall within the severe spectrum of many other genetic conditions.
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Kruszka P, Muenke M. Syndromes associated with holoprosencephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2018; 178:229-237. [PMID: 29770994 DOI: 10.1002/ajmg.c.31620] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2018] [Revised: 04/11/2018] [Accepted: 04/16/2018] [Indexed: 01/29/2023]
Abstract
Holoprosencephaly (HPE) is partial or complete failure of the forebrain to divide into hemispheres and can be an isolated finding or associated with a syndrome. Most cases of HPE are associated with a syndrome and roughly 40%-60% of fetuses with HPE have trisomy 13 which is the most common etiology of HPE. Other syndromes associated with HPE include additional aneuploidies like trisomy 18 and single gene disorders such as Smith-Lemli-Opitz syndrome. There are a number of syndromes such as pseudotrisomy 13 which do not have a known molecular etiology; therefore, this review has two parts: syndromes with a molecular diagnosis and syndromes where the etiology is yet to be found. As most HPE is syndromic, this review provides a comprehensive list and description of syndromes associated with HPE that may be used as a differential diagnosis and starting point for evaluating individuals with HPE.
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Affiliation(s)
- Paul Kruszka
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
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Travessa A, Dias P, Rocha P, Sousa AB. Prenatal diagnosis of holoprosencephaly associated with Smith-Lemli-Opitz syndrome (SLOS) in a 46,XX fetus. Taiwan J Obstet Gynecol 2018; 56:541-544. [PMID: 28805615 DOI: 10.1016/j.tjog.2017.01.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2017] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To show the importance of measuring cholesterol precursor levels in amniotic fluid in all pregnancies with ultrasound features (such as holoprosencephaly) suggestive of Smith-Lemli-Opitz syndrome (SLOS), after exclusion of chromosomal anomalies. CASE REPORT A 28-year-old woman, gravida 1 para 0, performed chorionic villus sampling for fetal karyotyping at 13 weeks of gestation due to positive combined first trimester screening in a fetus with increased nuchal translucency and suspected holoprosencephaly. The result was normal - 46,XX. The diagnosis of alobar holoprosencephaly was confirmed at 15 weeks of gestation, and cardiac and limb defects were also identified. Thus, a syndromic cause was considered, specifically a chromosomal microdeletion syndrome or a monogenic entity such as SLOS. The latter was confirmed by measuring 7-dehydrocholesterol (7DHC) and 8-dehydrocholesterol (8DHC) in amniotic fluid. Molecular analysis of DHCR7 gene identified a homozygous mutation in intron 8, c.964-1G>C, providing molecular confirmation for this diagnosis. CONCLUSION The differential diagnosis of holoprosencephaly is broad. Identification of the cause of holoprosencephaly aids in establishing the prognosis and is essential to ascertain the mode of inheritance for adequate genetic counseling.
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Affiliation(s)
- André Travessa
- Serviço de Genética, Departamento de Pediatria, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, Centro Académico de Medicina de Lisboa, Lisboa, Portugal.
| | - Patrícia Dias
- Serviço de Genética, Departamento de Pediatria, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, Centro Académico de Medicina de Lisboa, Lisboa, Portugal
| | - Pedro Rocha
- Serviço de Ginecologia-Obstetrícia, Hospital Beatriz Ângelo, Loures, Portugal
| | - Ana Berta Sousa
- Serviço de Genética, Departamento de Pediatria, Hospital de Santa Maria, Centro Hospitalar Lisboa Norte, Centro Académico de Medicina de Lisboa, Lisboa, Portugal
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Zeng Z, Liu F, Li S. Metabolic Adaptations in Pregnancy: A Review. ANNALS OF NUTRITION AND METABOLISM 2017; 70:59-65. [PMID: 28297696 DOI: 10.1159/000459633] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 02/02/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Pregnancy is a dynamic state involving multiple adaptations that are necessary in order to ensure a continuous supply of essential metabolites to support the growth and the development of the fetus. OBJECTIVES This review article is aimed to discuss important adaptations in metabolism that take place during non-complicated pregnancy. MATERIALS AND METHODS We searched the electronic database PubMed for pre-clinical as well as clinical controlled trials reporting the importance of metabolic adaptations during a non-complicated pregnancy. The preferred language was English and the most recent reports were selected to get an updated review. RESULTS It was observed clearly in the searched literature that metabolic adaptations are a crucial part of pregnancy, as they provide the mother with sufficient energy stores to meet the demands of pregnancy. These adaptions also help in preparing the mother for lactation and also help in providing proper environment for the proper growth of fetus in the womb. Moreover, multiple biomolecules including glucose, fatty acids, ketone bodies, hormones collectively contribute toward these metabolic adaptations. CONCLUSIONS This review article concludes that metabolic adaptations are crucial for proper fetus development.
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Affiliation(s)
- Zhandong Zeng
- Department of Pediatric Surgery, Xuzhou Children's Hospital, Xuzhou, PR China
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Shin S, Yu N, Choi JR, Jeong S, Lee KA. Routine chromosomal microarray analysis is necessary in Korean patients with unexplained developmental delay/mental retardation/autism spectrum disorder. Ann Lab Med 2016. [PMID: 26206688 PMCID: PMC4510504 DOI: 10.3343/alm.2015.35.5.510] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Background All over the world, chromosomal microarray (CMA) is now the first tier diagnostic assay for genetic testing to evaluate developmental delay (DD), mental retardation (MR), and autism spectrum disorder (ASD) with unknown etiology. The average diagnostic yield of the CMA test is known to be about 12.2%, while that of conventional G-banding karyotype is below 3%. This study aimed to assess the usefulness of CMA for the purpose of clinical diagnostic testing in the Korean population. Methods We performed CMA and multiplex ligation-dependent probe amplification (MLPA) tests in 96 patients with normal karyotype and unexplained DD, MR, or ASD. The CMA was conducted with CytoScan 750K array (Affymetrix, USA) with an average resolution of 100 kb. Results Pathogenic copy number variations (CNVs) were detected in 15 patients by CMA and in two patients by MLPA for four known microdeletion syndromes (Prader-Willi/Angelman syndrome, DiGeorge syndrome, Miller-Dieker syndrome and Williams syndrome) designated by National Health Insurance system in Korea. The diagnostic yield was 15.6% and 2.1%, respectively. Thirteen (13.5%) patients (excluding cases with pathogenic CNVs) had variants of uncertain clinical significance. There was one patient with a 17.1-megabase (Mb) region of homozygosity on chromosome 4q. Conclusions Our findings suggest the necessity of CMA as a routine diagnostic test for unexplained DD, MR, and ASD in Korea.
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Affiliation(s)
- Saeam Shin
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Nae Yu
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea
| | - Seri Jeong
- Department of Laboratory Medicine, Kosin University College of Medicine, Busan, Korea
| | - Kyung A Lee
- Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Korea.
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Bianconi SE, Cross JL, Wassif CA, Porter FD. Pathogenesis, Epidemiology, Diagnosis and Clinical Aspects of Smith-Lemli-Opitz Syndrome. Expert Opin Orphan Drugs 2015; 3:267-280. [PMID: 25734025 PMCID: PMC4343216 DOI: 10.1517/21678707.2015.1014472] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
INTRODUCTION Smith-Lemli-Opitz Syndrome (SLOS) is a malformation syndrome inherited in an autosomal recessive fashion. It is due to a metabolic defect in the conversion of 7-dehydrocholesterol to cholesterol, which leads to an accumulation of 7-dehydrocholesterol and frequently a deficiency of cholesterol. The syndrome is characterized by typical dysmorphic facial features, multiple malformations, and intellectual disability. AREAS COVERED In this paper we provide an overview of the clinical phenotype and discuss how the manifestations of the syndrome vary depending on the age of the patients. We then explore the underlying biochemical defect and pathophysiological alterations that may contribute to the many disease manifestations. Subsequently we explore the epidemiology and succinctly discuss population genetics as they relate to SLOS. The next section presents the diagnostic possibilities. Thereafter, the treatment and management as is standard of care are presented. EXPERT OPINION Even though the knowledge of the underlying molecular mutations and the biochemical alterations is being rapidly accumulated, there is currently no efficacious therapy addressing neurological dysfunction. We discuss the difficulty of treating this disorder, which manifests as a combination of a malformation syndrome and an inborn error of metabolism. A very important factor in developing new therapies is the need to rigorously establish efficacy in controlled trials.
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Affiliation(s)
- Simona E Bianconi
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10 Rm 9D42, Bethesda, MD 20892,
| | - Joanna L Cross
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10 CRC, Rm 1-3288, Bethesda, MD 20892
| | - Christopher A Wassif
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10 CRC, Rm 1-3288, Bethesda, MD 20892
| | - Forbes D Porter
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10, CRC, Rm 2571, Bethesda, MD 20892,
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Tang C, Pan Y, Luo H, Xiong W, Zhu H, Ruan H, Wang J, Zou C, Tang L, Iguchi T, Long F, Wu X. Hedgehog signaling stimulates the conversion of cholesterol to steroids. Cell Signal 2015; 27:487-97. [PMID: 25582983 DOI: 10.1016/j.cellsig.2015.01.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 12/19/2014] [Accepted: 01/05/2015] [Indexed: 12/28/2022]
Abstract
Cholesterol modification of Hedgehog (Hh) ligands is fundamental for the activity of Hh signaling, and cholesterol biosynthesis is also required for intracellular Hh signaling transduction. Here, we investigated the roles and underlying mechanism of Hh signaling in metabolism of cholesterol. The main components of the Hh pathway are abundantly expressed in both human cytotrophoblasts and trophoblast-like cells. Activation of Hh signaling induces the conversion of cholesterol to progesterone (P4) and estradiol (E2) through up-regulating the expression of steroidogenic enzymes including P450 cholesterol side chain cleavage enzyme (P450scc), 3β-hydroxysteroid dehydrogenase type 1 (3β-HSD1), and aromatase. Moreover, inhibition of Hh signaling attenuates not only Hh-induced expression of steroidogenic enzymes but also the conversion of cholesterol to P4 and E2. Whereas Gli3 is required for Hh-induced P450scc expression, Gli2 mediates the induction of 3β-HSD1 and aromatase. Finally, in ovariectomized nude mice, systemic inhibition of Hh signaling by cyclopamine suppresses circulating P4 and E2 levels derived from a trophoblast-like choricarcinoma xenograft, and attenuates uterine response to P4 and E2. Together these results uncover a hitherto uncharacterized role of Hh signaling in metabolism of cholesterol.
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Affiliation(s)
- Chao Tang
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Yibin Pan
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Huan Luo
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Wenyi Xiong
- The Affiliated Children Hospital, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Haibin Zhu
- The Affiliated First Hospital, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Hongfeng Ruan
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Jirong Wang
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Chaochun Zou
- The Affiliated Children Hospital, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Lanfang Tang
- The Affiliated Children Hospital, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Takuma Iguchi
- Department of Toxicology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Fanxin Long
- Departments of Orthopaedic Surgery, Medicine and Developmental Biology Washington University in St. Louis, MO, 63110, USA
| | - Ximei Wu
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, 310058, China; Departments of Orthopaedic Surgery, Medicine and Developmental Biology Washington University in St. Louis, MO, 63110, USA.
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Petryk A, Graf D, Marcucio R. Holoprosencephaly: signaling interactions between the brain and the face, the environment and the genes, and the phenotypic variability in animal models and humans. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2014; 4:17-32. [PMID: 25339593 DOI: 10.1002/wdev.161] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 09/08/2014] [Accepted: 09/19/2014] [Indexed: 01/17/2023]
Abstract
Holoprosencephaly (HPE) is the most common developmental defect of the forebrain characterized by inadequate or absent midline division of the forebrain into cerebral hemispheres, with concomitant midline facial defects in the majority of cases. Understanding the pathogenesis of HPE requires knowledge of the relationship between the developing brain and the facial structures during embryogenesis. A number of signaling pathways control and coordinate the development of the brain and face, including Sonic hedgehog, Bone morphogenetic protein, Fibroblast growth factor, and Nodal signaling. Mutations in these pathways have been identified in animal models of HPE and human patients. Because of incomplete penetrance and variable expressivity of HPE, patients carrying defined mutations may not manifest the disease at all, or have a spectrum of defects. It is currently unknown what drives manifestation of HPE in genetically at-risk individuals, but it has been speculated that other gene mutations and environmental factors may combine as cumulative insults. HPE can be diagnosed in utero by a high-resolution prenatal ultrasound or a fetal magnetic resonance imaging, sometimes in combination with molecular testing from chorionic villi or amniotic fluid sampling. Currently, there are no effective preventive methods for HPE. Better understanding of the mechanisms of gene-environment interactions in HPE would provide avenues for such interventions.
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Affiliation(s)
- Anna Petryk
- Department of Pediatrics, University of Minnesota, Minneapolis, MN, USA
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Lanthaler B, Hinderhofer K, Maas B, Haas D, Sawyer H, Burton-Jones S, Carter K, Suri M, Witsch-Baumgartner M. Characterization of large deletions in the DHCR7 gene. Clin Genet 2014; 88:149-54. [PMID: 25040602 DOI: 10.1111/cge.12454] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 07/01/2014] [Accepted: 07/02/2014] [Indexed: 11/27/2022]
Abstract
Pathogenic variants in the DHCR7 gene cause Smith-Lemli-Opitz syndrome (SLOS), a defect of cholesterol biosynthesis resulting in an autosomal recessive congenital metabolic malformation disorder. In approximately 4% of patients, the second mutation remains unidentified. In this study, 12 SLOS patients diagnosed clinically and/or by elevated 7-dehydrocholesterol (7-DHC) have been investigated by customized multiplex ligation-dependent probe amplification (MLPA) analysis, because only one DHCR7 sequence variant has been detected. Two unrelated patients of this cohort carry different large deletions in the DHCR7 gene. One patient showed a deletion of exons 3-6. The second patient has a deletion of exons 1 and 2 (non-coding) and lacks the major part of the promoter. These two patients show typical clinical and biochemical phenotypes of SLOS. Second disease-causing mutations are p.(Arg352Trp) and p.(Thr93Met), respectively. Deletion breakpoints were characterized successfully in both cases. Such large deletions are rare in the DHCR7 gene but will resolve some of the patients in whom a second mutation has not been detected.
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Affiliation(s)
- B Lanthaler
- Division of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - K Hinderhofer
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - B Maas
- Institute of Human Genetics, Heidelberg University, Heidelberg, Germany
| | - D Haas
- Division of Inborn Metabolic Diseases, University Children's Hospital, Heidelberg, Germany
| | - H Sawyer
- Bristol Genetics Laboratory, North Bristol NHS Trust, Bristol, UK
| | - S Burton-Jones
- Bristol Genetics Laboratory, North Bristol NHS Trust, Bristol, UK
| | - K Carter
- Nottingham Clinical Genetics Service, City Hospital Campus, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - M Suri
- Nottingham Clinical Genetics Service, City Hospital Campus, Nottingham University Hospitals NHS Trust, Nottingham, UK
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Lee RW, Conley SK, Gropman A, Porter FD, Baker EH. Brain magnetic resonance imaging findings in Smith-Lemli-Opitz syndrome. Am J Med Genet A 2013; 161A:2407-19. [PMID: 23918729 PMCID: PMC3787998 DOI: 10.1002/ajmg.a.36096] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 05/28/2013] [Indexed: 01/03/2023]
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is a neurodevelopmental disorder caused by inborn errors of cholesterol metabolism resulting from mutations in 7-dehydrocholesterol reductase (DHCR7). There are only a few studies describing the brain imaging findings in SLOS. This study examines the prevalence of magnetic resonance imaging (MRI) abnormalities in the largest cohort of patients with SLOS to date. Fifty-five individuals with SLOS (27 M, 28 F) between age 0.17 years and 25.4 years (mean = 6.2, SD = 5.8) received a total of 173 brain MRI scans (mean = 3.1 per subject) on a 1.5T GE scanner between September 1998 and December 2003, or on a 3T Philips scanner between October 2010 and September 2012; all exams were performed at the Clinical Center of the National Institutes of Health. We performed a retrospective review of these imaging studies for both major and minor brain anomalies. Aberrant MRI findings were observed in 53 of 55 (96%) SLOS patients, with abnormalities of the septum pellucidum the most frequent (42/55, 76%) finding. Abnormalities of the corpus callosum were found in 38 of 55 (69%) patients. Other findings included cerebral atrophy, cerebellar atrophy, colpocephaly, white matter lesions, arachnoid cysts, Dandy-Walker variant, and type I Chiari malformation. Significant correlations were observed when comparing MRI findings with sterol levels and somatic malformations. Individuals with SLOS commonly have anomalies involving the midline and para-midline structures of the brain. Further studies are required to examine the relationship between structural brain abnormalities and neurodevelopmental disability in SLOS.
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Affiliation(s)
- Ryan W.Y. Lee
- Department of Neurology andDevelopmental Medicine, Kennedy Krieger Institute, Baltimore, MD
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Sandra K. Conley
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Andrea Gropman
- Department of Neurology, Children’s National Medical Center, Washington DC
| | - Forbes D. Porter
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD
| | - Eva H. Baker
- Department of Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD
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20
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Lee RWY, Yoshida S, Jung ES, Mori S, Baker EH, Porter FD. Corpus callosum measurements correlate with developmental delay in Smith-Lemli-Opitz syndrome. Pediatr Neurol 2013; 49:107-12. [PMID: 23859856 PMCID: PMC3718481 DOI: 10.1016/j.pediatrneurol.2013.03.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 03/06/2013] [Accepted: 03/19/2013] [Indexed: 02/05/2023]
Abstract
BACKGROUND Smith-Lemli-Opitz syndrome (SLOS) is a multiple malformation, neurodevelopmental disorder of cholesterol metabolism caused by mutations in 7-dehydrocholesterol reductase. Corpus callosum (CC) malformations and developmental delay are common, but the relation between the two has not been evaluated. This study hypothesizes shorter callosal length and smaller area correlate with higher serum 7-dehydrocholesterol and increased severity of neurodevelopmental delay in SLOS. METHODS Thirty-six individuals with SLOS (18M/18F) between 0.20 and 12.5 years (mean = 3.9, SD = 3.6) and 36 typically developing controls (18 boys and 18 girls) between 0.12 and 12.8 years (mean = 4.0, SD = 3.6) were each imaged once on a 1.5T scanner. One midsagittal image per study was selected for manual CC measurement. Gross motor, fine motor, and language developmental quotients; anatomical severity score; and serum sterol levels were assessed. RESULTS Shorter CC length and smaller area correlated with a lower developmental quotient in gross motor and language domains. Furthermore, length and area negatively correlated with a serum sterol precursors and severity score, and positively correlated with total cholesterol. Degree of developmental delay ranged from mild to severe, involving all domains. CONCLUSIONS For individuals with SLOS, smaller callosal area and length are associated with higher 7-dehydrocholesterol, severity scores, and developmental delay. The relationship between callosal development and biochemical abnormalities in this cohort may lead to further studies supporting imaging biomarkers.
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Affiliation(s)
- Ryan W Y Lee
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, Maryland, USA.
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21
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Opitz JM, Furtado LV. The RSH/"Smith-Lemli-Opitz" syndrome: historical footnote. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:242-9. [PMID: 23059855 DOI: 10.1002/ajmg.c.31341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Thirty years after its clinical delineation in humans and its teratologic simulation in rats, a Garrodian error of metabolism was discovered in the autosomal recessive RSH/SLO syndrome, namely defective conversion of 7-dehydrocholesterol to cholesterol due to the mutant 7-dehydrocholesterol reductase. This opened the door to the study of several other defects of sterol biosynthesis in humans and the creation of animal "models." The gross discrepancy between expected and observed birth prevalence suggests high embryolethality. The discovery of the role of cholesterol in the synthesis of the morphogen sonic hedgehog has greatly advanced our understanding of mammalian development.
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Affiliation(s)
- John M Opitz
- American Journal of Medical Genetics, University of Utah, 419 Wakara Way, Ste 213, Salt Lake City, UT 84108, USA.
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Nowaczyk MJM, Irons MB. Smith-Lemli-Opitz syndrome: phenotype, natural history, and epidemiology. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:250-62. [PMID: 23059950 DOI: 10.1002/ajmg.c.31343] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is a congenital multiple anomaly/intellectual disability syndrome caused by a deficiency of cholesterol synthesis resulting from a deficiency of 7-dehydrocholesterol (7DHC) reductase encoded by DHCR7. SLOS is inherited in an autosomal recessive pattern. It is characterized by prenatal and postnatal growth retardation, microcephaly, a variable degree of intellectual disability that encompasses normal intelligence to severe intellectual deficiency, and multiple major and minor malformations. External malformations include distinctive facial features, cleft palate, postaxial polydactyly, 2-3 syndactyly of the toes, and underdeveloped external genitalia in males, while internal anomalies may affect every organ system. The clinical spectrum is wide, and rare individuals have been described with normal development and only minor malformations. The clinical diagnosis of SLOS is confirmed by demonstrating an abnormally elevated concentration of the cholesterol precursor, 7DHC, in serum or other tissues, or by the presence of two DHCR7 mutations. The enzymatic deficiency results in decreased cholesterol and increased 7DHC levels, both during embryonic development and after birth. The malformations found in SLOS may result from decreased cholesterol, increased 7DHC or a combination of these two factors. This review discusses the physical and behavioral phenotype of SLOS, the diagnostic approaches, the natural history from the prenatal period to adulthood, and current understanding of the pathophysiology of SLOS.
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Affiliation(s)
- Małgorzata J M Nowaczyk
- Department of Pathology and Molecular Medicine and Department of Pediatrics, McMaster University McMaster University Medical Centre, Room 3N16, 1200 Main Street West, Hamilton ON, Canada L8S 4J9.
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Waterham HR, Hennekam RCM. Mutational spectrum of Smith-Lemli-Opitz syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:263-84. [PMID: 23042628 DOI: 10.1002/ajmg.c.31346] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Smith-Lemli-Opitz syndrome (SLOS; OMIM #270400) is an autosomal recessive malformation syndrome characterized by a large spectrum of morphogenic and congenital anomalies. SLOS is caused by mutations in the DHCR7 gene, which encodes 7-dehydrocholesterol reductase, the enzyme that catalyzes the final step in cholesterol biosynthesis. We report on 154 currently known mutations in DHCR7 identified in patients affected with SLOS and discuss their coding consequences. These 154 mutations include 130 missense, 8 nonsense, 8 deletions, 2 insertions, 1 indel, and 5 splice site mutations. Using information available from published case reports and from patients identified in our clinical diagnostic laboratory, we analyzed correlations between genotype, clinical presentation and 7-dehydrocholesterol level.
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Affiliation(s)
- Hans R Waterham
- Laboratory Genetic Metabolic Diseases (F0-222), Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
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Aradhya S, Lewis R, Bonaga T, Nwokekeh N, Stafford A, Boggs B, Hruska K, Smaoui N, Compton JG, Richard G, Suchy S. Exon-level array CGH in a large clinical cohort demonstrates increased sensitivity of diagnostic testing for Mendelian disorders. Genet Med 2012; 14:594-603. [PMID: 22382802 DOI: 10.1038/gim.2011.65] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
PURPOSE Mendelian disorders are most commonly caused by mutations identifiable by DNA sequencing. Exonic deletions and duplications can go undetected by sequencing, and their frequency in most Mendelian disorders is unknown. METHODS We designed an array comparative genomic hybridization (CGH) test with probes in exonic regions of 589 genes. Targeted testing was performed for 219 genes in 3,018 patients. We demonstrate for the first time the utility of exon-level array CGH in a large clinical cohort by testing for 136 autosomal dominant, 53 autosomal recessive, and 30 X-linked disorders. RESULTS Overall, 98 deletions and two duplications were identified in 53 genes, corresponding to a detection rate of 3.3%. Approximately 40% of positive findings were deletions of only one or two exons. A high frequency of deletions was observed for several autosomal dominant disorders, with a detection rate of 2.9%. For autosomal recessive disorders, array CGH was usually performed after a single mutation was identified by sequencing. Among 138 individuals tested for recessive disorders, 10.1% had intragenic deletions. For X-linked disorders, 3.5% of 313 patients carried a deletion or duplication. CONCLUSION Our results demonstrate that exon-level array CGH provides a robust option for intragenic copy number analysis and should routinely supplement sequence analysis for Mendelian disorders.
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Quélin C, Loget P, Verloes A, Bazin A, Bessières B, Laquerrière A, Patrier S, Grigorescu R, Encha-Razavi F, Delahaye S, Jouannic JM, Carbonne B, D’Hervé D, Aubry MC, Macé G, Harvey T, Ville Y, Viot G, Joyé N, Odent S, Attié-Bitach T, Wolf C, Chevy F, Benlian P, Gonzales M. Phenotypic spectrum of fetal Smith–Lemli–Opitz syndrome. Eur J Med Genet 2012; 55:81-90. [DOI: 10.1016/j.ejmg.2011.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 12/13/2011] [Indexed: 11/25/2022]
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Raam MS, Solomon BD, Muenke M. Holoprosencephaly: a guide to diagnosis and clinical management. Indian Pediatr 2011; 48:457-66. [PMID: 21743112 DOI: 10.1007/s13312-011-0078-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
CONTEXT Holoprosencephaly affects 1 in 8,000 live births and is the most common structural anomaly of the developing forebrain, resulting in facial dysmorphism, neurologic impairment, and additional clinical sequelae. Given the increasing relative contribution of genetic diseases to perinatal morbidity and mortality in India, proper recognition and management of holoprosencephaly can improve care for a significant number of affected Indian children. EVIDENCE ACQUISITION We used the PubMed database (search terms: "holoprosencephaly," "HPE," "holoprosencephaly India") and cross-referenced articles regarding holoprosencephaly, using our research group's extensive experience as a guide for identifying seminal papers in the field. RESULTS Holoprosencephaly is classified into four types based on the nature of the brain malformations as seen on neuroimaging and/or pathologic examination, with typically recognizable craniofacial phenotypes. Despite the identification of several genetic loci and other etiologic agents involved in pathogenesis, additional causes are elusive. Moreover, satisfactory explanations for phenomena such as incomplete penetrance and variable expressivity are lacking. CONCLUSIONS For each patient, pediatricians should follow a diagnostic protocol including dysmorphology examination, complete family history and ascertainment of risk factors, and neuroimaging. Many medical issues, including hypothalamic dysfunction, endocrinologic dysfunction, motor impairment, respiratory issues, seizures, and hydrocephalus should be prioritized in management. Pediatricians should work with genetic specialists to identify syndromic forms and to perform cytogenetic investigation, molecular screening, and genetic counseling in order to fully characterize prognosis and recurrence risk.
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Affiliation(s)
- Manu S Raam
- HHMI-NIH Research Scholars Program, Howard Hughes Medical Institute, Chevy Chase, MD, United States
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Orioli IM, Amar E, Bakker MK, Bermejo-Sánchez E, Bianchi F, Canfield MA, Clementi M, Correa A, Csáky-Szunyogh M, Feldkamp ML, Landau D, Leoncini E, Li Z, Lowry RB, Mastroiacovo P, Morgan M, Mutchinick OM, Rissmann A, Ritvanen A, Scarano G, Szabova E, Castilla EE. Cyclopia: an epidemiologic study in a large dataset from the International Clearinghouse of Birth Defects Surveillance and Research. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2011; 157C:344-57. [PMID: 22006661 DOI: 10.1002/ajmg.c.30323] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cyclopia is characterized by the presence of a single eye, with varying degrees of doubling of the intrinsic ocular structures, located in the middle of the face. It is the severest facial expression of the holoprosencephaly (HPE) spectrum. This study describes the prevalence, associated malformations, and maternal characteristics among cases with cyclopia. Data originated in 20 Clearinghouse (ICBDSR) affiliated birth defect surveillance systems, reported according to a single pre-established protocol. A total of 257 infants with cyclopia were identified. Overall prevalence was 1 in 100,000 births (95%CI: 0.89-1.14), with only one program being out of range. Across sites, there was no correlation between cyclopia prevalence and number of births (r = 0.08; P = 0.75) or proportion of elective termination of pregnancy (r = -0.01; P = 0.97). The higher prevalence of cyclopia among older mothers (older than 34) was not statistically significant. The majority of cases were liveborn (122/200; 61%) and females predominated (male/total: 42%). A substantial proportion of cyclopias (31%) were caused by chromosomal anomalies, mainly trisomy 13. Another 31% of the cases of cyclopias were associated with defects not typically related to HPE, with more hydrocephalus, heterotaxia defects, neural tube defects, and preaxial reduction defects than the chromosomal group, suggesting the presence of ciliopathies or other unrecognized syndromes. Cyclopia is a very rare defect without much variability in prevalence by geographic location. The heterogeneous etiology with a high prevalence of chromosomal abnormalities, and female predominance in HPE, were confirmed, but no effect of increased maternal age or association with twinning was observed.
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Affiliation(s)
- Iêda M Orioli
- Estudo Colaborativo Latino Americano de Malformações Congênitas at Departamento de Genética, Instituto de Biologia, Rio de Janeiro, Brazil.
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Bidet M, Joubert O, Lacombe B, Ciantar M, Nehmé R, Mollat P, Brétillon L, Faure H, Bittman R, Ruat M, Mus-Veteau I. The hedgehog receptor patched is involved in cholesterol transport. PLoS One 2011; 6:e23834. [PMID: 21931618 PMCID: PMC3169562 DOI: 10.1371/journal.pone.0023834] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 07/26/2011] [Indexed: 01/09/2023] Open
Abstract
Background Sonic hedgehog (Shh) signaling plays a crucial role in growth and patterning during embryonic development, and also in stem cell maintenance and tissue regeneration in adults. Aberrant Shh pathway activation is involved in the development of many tumors, and one of the most affected Shh signaling steps found in these tumors is the regulation of the signaling receptor Smoothened by the Shh receptor Patched. In the present work, we investigated Patched activity and the mechanism by which Patched inhibits Smoothened. Methodology/Principal Findings Using the well-known Shh-responding cell line of mouse fibroblasts NIH 3T3, we first observed that enhancement of the intracellular cholesterol concentration induces Smoothened enrichment in the plasma membrane, which is a crucial step for the signaling activation. We found that binding of Shh protein to its receptor Patched, which involves Patched internalization, increases the intracellular concentration of cholesterol and decreases the efflux of a fluorescent cholesterol derivative (BODIPY-cholesterol) from these cells. Treatment of fibroblasts with cyclopamine, an antagonist of Shh signaling, inhibits Patched expression and reduces BODIPY-cholesterol efflux, while treatment with the Shh pathway agonist SAG enhances Patched protein expression and BODIPY-cholesterol efflux. We also show that over-expression of human Patched in the yeast S. cerevisiae results in a significant boost of BODIPY-cholesterol efflux. Furthermore, we demonstrate that purified Patched binds to cholesterol, and that the interaction of Shh with Patched inhibits the binding of Patched to cholesterol. Conclusion/Significance Our results suggest that Patched may contribute to cholesterol efflux from cells, and to modulation of the intracellular cholesterol concentration. This activity is likely responsible for the inhibition of the enrichment of Smoothened in the plasma membrane, which is an important step in Shh pathway activation.
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Affiliation(s)
- Michel Bidet
- Université de Nice - Sophia Antipolis, CNRS-UMR 6543, Institute of Developmental Biology and Cancer, Nice, France
| | - Olivier Joubert
- Université de Nice - Sophia Antipolis, CNRS-UMR 6543, Institute of Developmental Biology and Cancer, Nice, France
- Université Henri Poincaré- Nancy 1, EA 3452, Faculté de Pharmacie, Nancy, France
| | - Benoit Lacombe
- Université de Nice - Sophia Antipolis, CNRS-UMR 6543, Institute of Developmental Biology and Cancer, Nice, France
| | - Marine Ciantar
- Université de Nice - Sophia Antipolis, CNRS-UMR 6543, Institute of Developmental Biology and Cancer, Nice, France
| | - Rony Nehmé
- Université de Nice - Sophia Antipolis, CNRS-UMR 6543, Institute of Developmental Biology and Cancer, Nice, France
- Laboratory of Molecular Biology, Medical Research Council (MRC), Cambridge, United Kingdom
| | | | - Lionel Brétillon
- Université de Bourgogne, CNRS-INRA, Centre des Sciences du Goût et de l'Alimentation, Dijon, France
| | - Hélène Faure
- CNRS, UPR-3294, Laboratoire de Neurobiologie et Développement, Institut de Neurobiologie Alfred Fessard IFR2118, Gif-sur-Yvette, France
| | - Robert Bittman
- Department of Chemistry and Biochemistry, Queens College of the City University of New York, Flushing, New York, United States of America
| | - Martial Ruat
- CNRS, UPR-3294, Laboratoire de Neurobiologie et Développement, Institut de Neurobiologie Alfred Fessard IFR2118, Gif-sur-Yvette, France
| | - Isabelle Mus-Veteau
- Université de Nice - Sophia Antipolis, CNRS-UMR 6543, Institute of Developmental Biology and Cancer, Nice, France
- * E-mail:
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Kauvar EF, Hu P, Pineda-Alvarez DE, Solomon BD, Dutra A, Pak E, Blessing B, Proud V, Shanske AL, Stevens CA, Rosenfeld JA, Shaffer LG, Roessler E, Muenke M. Minimal evidence for a direct involvement of twisted gastrulation homolog 1 (TWSG1) gene in human holoprosencephaly. Mol Genet Metab 2011; 102:470-80. [PMID: 21227728 PMCID: PMC3152819 DOI: 10.1016/j.ymgme.2010.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 12/14/2010] [Accepted: 12/14/2010] [Indexed: 10/18/2022]
Abstract
Holoprosencephaly (HPE) is the most common disorder of human forebrain and facial development. Presently understood etiologies include both genetic and environmental factors, acting either alone, or more likely, in combination. The majority of patients without overt chromosomal abnormalities or recognizable associated syndromes have unidentified etiologies. A potential candidate gene, Twisted Gastrulation Homolog 1 (TWSG1), was previously suggested as a contributor to the complex genetics of human HPE based on (1) cytogenetic studies of patients with 18p deletions, (2) animal studies of TWSG1 deficient mice, and (3) the relationship of TWSG1 to bone morphogenetic protein (BMP) signaling, which modulates the primary pathway implicated in HPE, Sonic Hedgehog (SHH) signaling. Here we present the first analysis of a large cohort of patients with HPE for coding sequence variations in TWSG1. We also performed fine mapping of 18p for a subset of patients with partial 18p deletions. Surprisingly, minimal evidence for alterations of TWSG1 was found, suggesting that sequence alterations of TWSG1 are neither a common direct cause nor a frequent modifying factor for human HPE pathologies.
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Affiliation(s)
- Emily F. Kauvar
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Howard Hughes Medical Institute – National Institutes of Health Research Scholars Program, Bethesda, MD, USA
| | - Ping Hu
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Daniel E. Pineda-Alvarez
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Benjamin D. Solomon
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Amalia Dutra
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Evgenia Pak
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Brooke Blessing
- Division of Medical Genetics, Children’s Hospital of The King’s Daughters, Norfolk, VA, USA
| | - Virginia Proud
- Division of Medical Genetics, Children’s Hospital of The King’s Daughters, Norfolk, VA, USA
| | - Alan L. Shanske
- Center for Craniofacial Disorders, Children’s Hospital at Montefiore Medical Center, Bronx, NY, USA
| | - Cathy A. Stevens
- Department of Pediatrics, University of Tennessee College of Medicine, Chattanooga, TN, USA
| | | | | | - Erich Roessler
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Maximilian Muenke
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Corresponding author: Address: 35 Convent Drive, MSC 3717, Bldg 35, Rm 1B-203, Bethesda, MD, 20892-3717, USA. Tel: (301) 402-8167. Fax: (301) 480-7876. (M. Muenke)
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Abstract
PURPOSE OF REVIEW This review presents recent advances in our understanding and clinical management of holoprosencephaly (HPE). HPE is the most common developmental disorder of the human forebrain and involves incomplete or failed separation of the cerebral hemispheres. The epidemiology, clinical features, causes, diagnostic approach, management, and outcomes of HPE are discussed. RECENT FINDINGS Chromosomal abnormalities account for the most commonly identified cause of HPE. However, there are often unidentifiable causes in patients with nonsyndromic, nonchromosomal forms of HPE. The prevalence of HPE may be underestimated given that patients with mild forms often are not diagnosed until they present with severely affected children. Pregestational maternal diabetes mellitus is the most recognized risk factor for HPE, as supported by recent large-scale epidemiological studies. Genetic studies using microarray-based comparative genomic hybridization technology have resulted in better characterization of important HPE loci. SUMMARY HPE encompasses a wide spectrum of forebrain and midline defects, with an accompanying wide spectrum of clinical manifestations. A coordinated, multidisciplinary care team is required for clinical management of this complex disorder. Further research will enable us to better understand the pathogenesis and causes of HPE, and thus to improve the genetic counseling of patients and their families.
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Abstract
In vertebrate hedgehog signaling, hedgehog ligands are processed to become bilipidated and then multimerize, which allows them to leave the signaling cell via Dispatched 1 and become transported via glypicans and megalin to the responding cells. Hedgehog then interacts with a complex of Patched 1 and Cdo/Boc, which activates endocytic Smoothened to the cilium. Patched 1 regulates the activity of Smoothened (1) via Vitamin D3, which inhibits Smoothened in the absence of hedgehog ligand or (2) via oxysterols, which activate Smoothened in the presence of hedgehog ligand. Hedgehog ligands also interact with Hip1, Patched 2, and Gas1, which regulate the range as well as the level of hedgehog signaling. In vertebrates, Smoothened is shortened at its C-terminal end and lacks most of the phosphorylation sites of importance in Drosophila. Cos2, also of importance in Drosophila, plays no role in mammalian transduction, nor do its homologs Kif7 and Kif27. The cilium may provide a function analogous to that of Cos2 by linking Smoothened to the modulation of Gli transcription factors. Disorders associated with the hedgehog signaling network follow, including nevoid basal cell carcinoma syndrome, holoprosencephaly, Smith-Lemli-Opitz syndrome, Greig cephalopolysyndactyly syndrome, Pallister-Hall syndrome, Carpenter syndrome, and Rubinstein-Taybi syndrome.
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Affiliation(s)
- M Michael Cohen
- Department of Pediatrics, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
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32
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Porter FD, Herman GE. Malformation syndromes caused by disorders of cholesterol synthesis. J Lipid Res 2010; 52:6-34. [PMID: 20929975 DOI: 10.1194/jlr.r009548] [Citation(s) in RCA: 311] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cholesterol homeostasis is critical for normal growth and development. In addition to being a major membrane lipid, cholesterol has multiple biological functions. These roles include being a precursor molecule for the synthesis of steroid hormones, neuroactive steroids, oxysterols, and bile acids. Cholesterol is also essential for the proper maturation and signaling of hedgehog proteins, and thus cholesterol is critical for embryonic development. After birth, most tissues can obtain cholesterol from either endogenous synthesis or exogenous dietary sources, but prior to birth, the human fetal tissues are dependent on endogenous synthesis. Due to the blood-brain barrier, brain tissue cannot utilize dietary or peripherally produced cholesterol. Generally, inborn errors of cholesterol synthesis lead to both a deficiency of cholesterol and increased levels of potentially bioactive or toxic precursor sterols. Over the past couple of decades, a number of human malformation syndromes have been shown to be due to inborn errors of cholesterol synthesis. Herein, we will review clinical and basic science aspects of Smith-Lemli-Opitz syndrome, desmosterolosis, lathosterolosis, HEM dysplasia, X-linked dominant chondrodysplasia punctata, Congenital Hemidysplasia with Ichthyosiform erythroderma and Limb Defects Syndrome, sterol-C-4 methyloxidase-like deficiency, and Antley-Bixler syndrome.
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Affiliation(s)
- Forbes D Porter
- Program in Developmental Genetics and Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Department of Health and Human Services, Bethesda, MD 20892, USA.
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Haas D, Muenke M. Abnormal sterol metabolism in holoprosencephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:102-8. [PMID: 20104605 DOI: 10.1002/ajmg.c.30243] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Holoprosencephaly (HPE) is the most common structural malformation of the developing forebrain in humans. The HPE phenotype is extremely variable and the etiology is heterogeneous. Among a variety of embryological toxins that can induce HPE, inhibitors, and other pertubations of cholesterol biosynthesis have been shown to be important factors, most likely because cholesterol is required in the Sonic hedgehog signaling cascade. Decreased levels of maternal cholesterol during pregnancy increase the risk for preterm delivery, but they are not associated with congenital malformations. However, if the fetus is affected by an inborn error of endogenous cholesterol synthesis, a reduction of maternal cholesterol concentration and cholesterol transport over the placenta aggravates the phenotypic expression. Exposure to lipophilic statins in early pregnancy may be associated with a substantial risk for structural CNS defects.
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Affiliation(s)
- Dorothea Haas
- University Children's Hospital of Heidelberg, Germany.
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Mercier S, Dubourg C, Belleguic M, Pasquier L, Loget P, Lucas J, Bendavid C, Odent S. Genetic counseling and "molecular" prenatal diagnosis of holoprosencephaly (HPE). AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:191-6. [PMID: 20104616 DOI: 10.1002/ajmg.c.30246] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Holoprosencephaly (HPE) is a structural anomaly of the developing brain in which the forebrain fails to divide into two separate hemispheres and ventricles. The poor prognosis in the most severe forms justifies the importance of genetic counseling in affected families. The genetic counseling requires a thorough clinical approach given the extreme variability of phenotype and etiology. The karyotype is an essential diagnostic tool. Since mutations in the four major genes (SHH, ZIC2, SIX3, and TGIF) have been identified in HPE patients, molecular study is performed routinely in nonsyndromic HPE. New molecular tools, such as array-CGH analysis, are now part of the diagnostic process. Prenatal diagnosis is based primarily on fetal imaging, but "molecular" prenatal diagnosis can be performed if a mutation has been previously identified in a proband. Interpretations of molecular diagnosis must be given with caution, given the lack of strict genotype-phenotype correlation, and should be offered in addition to fetal imaging, using ultrasound followed by fetal MRI. We report on our experience of 15 molecular prenatal diagnoses from chorionic villi or amniotic fluid sampling. In eight instances, we were able to reassure the parents after taking into account the absence of the mutation in the fetus, previously identified before in a parent and/or a proband. Fetal RMI was normal later in pregnancy, and no child had medical problems after birth. The mutation was found in the seven other cases: four children were born, either without brain malformation and asymptomatic, or had a less severe form than the index case.
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Miller EA, Rasmussen SA, Siega-Riz AM, Frías JL, Honein MA. Risk factors for non-syndromic holoprosencephaly in the National Birth Defects Prevention Study. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2010; 154C:62-72. [PMID: 20104597 DOI: 10.1002/ajmg.c.30244] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Holoprosencephaly (HPE) is a complex structural brain anomaly that results from incomplete cleavage of the forebrain. The prevalence of HPE at birth is low, and risk factors have been difficult to identify. Using data from a large multi-state population-based case-control study, we examined risk factors for non-syndromic HPE. Data from maternal telephone interviews were available for 74 infants with HPE and 5871 controls born between 1997 and 2004. Several characteristics and exposures were examined, including pregnancy history, medical history, maternal diet and use of nutritional supplements, medications, tobacco, alcohol, and illegal substances. We used chi(2)-tests and logistic regression (excluding women with pre-existing diabetes) to examine associations with HPE. Except for diet (year before pregnancy) and sexually transmitted infections (STIs) (throughout pregnancy), most exposures were examined for the time period from the month before to the third month of pregnancy. HPE was found to be associated with pre-existing diabetes (chi(2) = 6.0; P = 0.01), aspirin use [adjusted odds ratio (aOR) = 3.4; 95% confidence interval (CI) 1.6-6.9], lower education level (aOR = 2.5; 95%CI 1.1-5.6), and use of assisted reproductive technologies (ART) (crude OR = 4.2; 95%CI 1.3-13.7). Consistent maternal folic acid use appeared to be protective (aOR = 0.4; 95%CI 0.2-1.0), but the association was of borderline statistical significance. While some of these findings support previous observations, other potential risk factors identified warrant further study.
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Affiliation(s)
- Eric A Miller
- Texas Department of State Health Services, Austin, 78714-9347, USA.
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