Adams-Oliver syndrome review of the literature: Refining the diagnostic phenotype

A Child with a Congenital Aplasia of the Scalp: A Quiz

Abstract is missing (Quiz)

Expanding the phenotypic spectrum of NOTCH1 variants: clinical manifestations in families with congenital heart disease

Pathogenic variants in NOTCH1 are associated with non-syndromic congenital heart disease (CHD) and Adams-Oliver syndrome (AOS). The clinical presentation of individuals with damaging NOTCH1 variants is characterized by variable expressivity and incomplete penetrance; however, data on systematic phenotypic characterization are limited. We report the genotype and phenotype of a cohort of 33 individuals (20 females, 13 males; median age 23.4 years, range 2.5-68.3 years) from 11 families with causative NOTCH1 variants (9 inherited, 2 de novo; 9 novel), ascertained from a proband with CHD. We describe the cardiac and extracardiac anomalies identified in these 33 individuals, only four of whom met criteria for AOS. The most common CHD identified was tetralogy of Fallot, though various left- and right-sided lesions and septal defects were also present. Extracardiac anomalies identified include cutis aplasia (5/33), cutaneous vascular anomalies (7/33), vascular anomalies of the central nervous system (2/10), Poland anomaly (1/33), pulmonary hypertension (2/33), and structural brain anomalies (3/14). Identification of these findings in a cardiac proband cohort supports NOTCH1-associated CHD and NOTCH1-associated AOS lying on a phenotypic continuum. Our findings also support (1) Broad indications for NOTCH1 molecular testing (any familial CHD, simplex tetralogy of Fallot or hypoplastic left heart); (2) Cascade testing in all at-risk relatives; and (3) A thorough physical exam, in addition to cardiac, brain (structural and vascular), abdominal, and ophthalmologic imaging, in all gene-positive individuals. This information is important for guiding the medical management of these individuals, particularly given the high prevalence of NOTCH1 variants in the CHD population.

Understanding the Genetic and Non-Genetic Interconnections in the Aetiology of Syndromic Congenital Heart Disease: An Updated Review: Part 2

PURPOSE OF REVIEW

Approximately 30% of syndromic cases diagnosed with CHD, which lure us to further investigate the molecular and clinical challenges behind syndromic CHD (sCHD). The aetiology of sCHD in a majority of cases remains enigmatic due to involvement of multiple factors, namely genetic, epigenetic and environmental modifiable risk factors for the development of the disease. Here, we aim to update the role of genetic contributors including chromosomal abnormalities, copy number variations (CNVs) and single gene mutations in cardiac specific genes, maternal lifestyle conditions, environmental exposures and epigenetic modifiers in causing CHD in different genetic syndromes.

RECENT FINDINGS

The exact aetiology of sCHD is still unknown. With the advancement of next-generation technologies including WGS, WES, transcriptome, proteome and methylome study, numerous novel genes and pathways have been identified. Moreover, our recent knowledge regarding epigenetic and environmental regulation during cardiogenesis is still evolving and may solve some of the mystery behind complex sCHD. Here, we focus to understand how the complex combination of genetic, environmental and epigenetic factors interact to interfere with developmental pathways, culminating into cardiac and extracardiac defects in sCHD.

Recent Advances in Pediatric Pulmonary Hypertension: Implications for Diagnosis and Treatment

PURPOSE

Pediatric pulmonary hypertension (PH) is a condition characterized by elevated pulmonary arterial pressure, which has the potential to be life-limiting. The etiology of pediatric PH varies. When compared with adult cohorts, the etiology is often multifactorial, with contributions from prenatal, genetic, and developmental factors. This review aims to provide an up-to-date overview of the causes and classification of pediatric PH, describe current therapeutics in pediatric PH, and discuss upcoming and necessary research in pediatric PH.

METHODS

PubMed was searched for articles relating to pediatric pulmonary hypertension, with a particular focus on articles published within the past 10 years. Literature was reviewed for pertinent areas related to this topic.

FINDINGS

The evaluation and approach to pediatric PH are unique when compared with that of adults, in large part because of the different, often multifactorial, causes of the disease in children. Collaborative registry studies have found that the most common disease causes include developmental lung disease and subsets of pulmonary arterial hypertension, which includes genetic variants and PH associated with congenital heart disease. Treatment with PH-targeted therapies in pediatrics is often guided by extrapolation of adult data, small clinical studies in pediatrics, and/or expert consensus opinion. We review diagnostic considerations and treatment in some of the more common pediatric subpopulations of patients with PH, including developmental lung diseases, congenital heart disease, and trisomy 21.

IMPLICATIONS

The care of pediatric patients with PH requires consideration of unique pediatric-specific factors. With significant variability in disease etiology, ongoing efforts are needed to optimize treatment strategies based on disease phenotype and guide evidence-based practices.

A novel pathogenic variation of DOCK6 gene: the genotype-phenotype correlation in Adams-Oliver syndrome

BACKGROUND

Adams-Oliver syndrome (AOS) (#614,219) is a multiple malformation disorder characterized by the presence of aplasia cutis congenita (ACC) and transverse terminal limb defects (TTLD).

METHODS AND RESULTS

We describe a confirmed case of AOS with a novel pathogenic variation in Dedicator Of Cytokinesis 6 (DOCK6) gene, with neurological abnormalities, characterized by the presence of a multiple malformation entity with extensive cardiological and neurological abnormalities.

CONCLUSIONS

In AOS, genotype-phenotype correlations have been described. DOCK6 mutations appear to be related with congenital cardiac and central nervous system malformations associated with intellectual disability, as illustrated in the present case.

Severe Adams-Oliver Syndrome after Maternal COVID-19 Infection Could Be Another Effect of the SARS-CoV-2 Inflammatory Storm? Case Report

Background. Adams-Oliver syndrome is a congenital disease whose main findings are aplasia cutis congenita of the scalp and terminal transverse limb defects. The pathogenesis is unknown, but it is postulated that ischemic events in susceptible tissues cause the lesions in the embryonic period.Case report. We present a newborn with a severe phenotype of Adams-Oliver syndrome. The infant's mother had a SARS-CoV-2 infection in the first trimester of pregnancy. Prenatal ultrasound indicates a probable worsening of the disease after the first trimester.Conclusion. This study shows a previously unpublished severe AOS phenotype in a term newborn. There are some signs that the disease could have progressed beyond the first trimester, either spontaneously or by the inflammatory mechanisms of SARS-CoV-2.

Case report: Recombinant human epidermal growth factor gel plus kangfuxin solution in the treatment of aplasia cutis congenita in a case with Adams-Oliver syndrome

Background

Aplasia cutis congenita is a congenital disorder with the absence of skin, muscle and(or) bone. It usually affects the scalp. The presence of a large scalp defect can be potentially serious when complicated with hemorrhage and infection. Early healing of this condition is beneficial to improve the prognosis of infants.

Study case

A full-term newborn male was born with a round-shaped defect at the vertex of the scalp and skull (dimensions, 8 cm × 9 cm). The infant had a large deletion encompassing the 15.1 region of chromosome 15, including the DLL4 gene. Genetic testing was positive for Adams-Oliver syndrome (AOS). After two months of recombinant human epidermal growth factor gel combined with kangfuxin solution therapy, the skin defects of the scalp healed remarkably. The infant had regular follow-up appointments. At the age of 5 months, the defect became smaller, hairless, and showed good granulation tissue. At 2 years of age, the child's Gesell Developmental Schedules was 70.

Conclusion

Recombinant human epidermal growth factor gel combined with kangfuxin solution was a successful conservative treatment for an infant with a large scalp defect accompanied by AOS.

Adams-Oliver syndrome

The article presents the observation of a rare hereditary disease: Adams–Oliver syndrome. In a newborn girl in the postnatal period, a lesion of the distal extremities was revealed in the form of syndactyly of the proximal phalanges of 4–5 and 2–3 fingers, hypoplasia of the nail phalanges of 2–5 fingers of the left foot, fusion of the proximal phalanges and the absence of middle and nail phalanges of 2–3 fingers of the right foot, hypoplasia of the terminal phalanx and the absence of the nail plate of the 2nd finger of the left hand. In addition to malformations of the extremities, anomalies in the development of the skin on the scalp in the form of an area of aplasia and outgrowths, represented by sweat gland hyperplasia with a fibroepithelial outgrowth, were noted. Cardiac pathology was manifested by a heart rhythm disturbance of the type of sinus bradyarrhythmia. Adams–Oliver syndrome is a complex disease with phenotypic variability, which causes difficulties in clinical diagnosis.

Adams-Oliver syndrome and associated complications: Report of a family in Colombia and review of the literature

The Adams-Oliver syndrome is a rare congenital disorder characterized by aplasia cutis congenita of the scalp, terminal transverse limb defects, and congenital telangiectatic cutis marmorata. It can occur through different inheritance patterns: autosomal dominant, autosomal recessive, or de novo dominant mutations. Although the Adams-Oliver syndrome is a rare disease, it is essential to know its clinical characteristics and inheritance patterns, to establish a correct diagnosis and its possible complications during follow-up. In the present study, we describe the case of an adolescent with Adams-Oliver syndrome with an autosomal dominant inheritance pattern, pulmonary hypertension and plastic bronchitis, and several compromised family members.

FOSL2 truncating variants in the last exon cause a neurodevelopmental disorder with scalp and enamel defects

PURPOSE

We aimed to investigate the molecular basis of a novel recognizable neurodevelopmental syndrome with scalp and enamel anomalies caused by truncating variants in the last exon of the gene FOSL2, encoding a subunit of the AP-1 complex.

METHODS

Exome sequencing was used to identify genetic variants in all cases, recruited through Matchmaker exchange. Gene expression in blood was analyzed using reverse transcription polymerase chain reaction. In vitro coimmunoprecipitation and proteasome inhibition assays in transfected HEK293 cells were performed to explore protein and AP-1 complex stability.

RESULTS

We identified 11 individuals from 10 families with mostly de novo truncating FOSL2 variants sharing a strikingly similar phenotype characterized by prenatal growth retardation, localized cutis scalp aplasia with or without skull defects, neurodevelopmental delay with autism spectrum disorder, enamel hypoplasia, and congenital cataracts. Mutant FOSL2 messenger RNAs escaped nonsense-mediated messenger RNA decay. Truncated FOSL2 interacts with c-JUN, thus mutated AP-1 complexes could be formed.

CONCLUSION

Truncating variants in the last exon of FOSL2 associate a distinct clinical phenotype by altering the regulatory degradation of the AP-1 complex. These findings reveal a new role for FOSL2 in human pathology.

PROLIFERATIVE RETINOPATHY IN A 13-YEAR-OLD WITH ADAMS-OLIVER SYNDROME

PURPOSE

Adams-Oliver syndrome is a rare, inherited disorder of embryologic development that affects multiple systems. Ocular manifestations have been poorly characterized because of the low prevalence and high mortality of the disease when it is associated with internal organ and/or ophthalmic manifestations. We present a case of Adams-Oliver syndrome in a 13-year-old patient whose multimodal retinal imaging findings helped direct management.

METHODS

Single patient case report reviewing medical records and imaging.

RESULTS

Visual acuity upon presentation was 20/40 in each eye. Ultra-widefield fluorescein angiography revealed peripheral nonperfusion with terminal vascular bulbs, and leakage from a temporal fibrovascular complex in the left eye. Fundus autofluorescence imaging showed hyperautofluorescence associated with optic disc drusen and the fibrovascular complex. Treatment with targeted laser photocoagulation was associated with regression of the neovascularization.

CONCLUSION

Retinal manifestations of Adams-Oliver syndrome as observed with ultra-widefield fundus imaging may resemble those of familial exudative vitreoretinopathy and retinopathy of prematurity. Treatment of avascular retina with panretinal photocoagulation can be considered.

High urinary CXCL10/Cr with onset of Burkitt lymphoma in a pediatric kidney transplant recipient

BACKGROUND

Urinary CXCL10/Cr is a promising diagnostic tool for early detection of TCMR in pediatric transplant recipients, and most studies focus on its utility in the context of localized allograft inflammation thus far. Other sources of inflammation that may be detected by CXCL10 are less clear.

METHODS

We present a case review of a patient with BL, who was enrolled in a prospective trial of urinary CXCL10 monitoring. To evaluate the potential confounding, we tested for association of CXCL10/Cr and EBV viral load in a prospective cohort of pediatric transplant recipients with serial testing for urinary CXCL10/Cr.

RESULTS

This report describes a 15-year-old boy, 3.5 years post-transplant with chronic EBV viremia, stable kidney function and no history of rejection. Urinary CXCL10/Cr level increased acutely to 79.43 ng/mmol, 0.8 months prior to onset of BL, identified by a surge in EBV viral load. In a national cohort of 97 pediatric kidney transplant recipients, there was no association between urinary CXCL10/Cr with EBV viral loads when comparing periods of pre-viremia (5.8 ± 9.2 ng/mmol) to active viremia (4.0 ± 5.3 ng/mmol) and periods of active viremia (7.1 ± 8.9 ng/mmol) to post-viremia (4.4 ± 9.8 ng/mmol).

CONCLUSIONS

Acute rise in urinary CXCL10/Cr was associated with onset of graft-associated BL. We were not able to confirm a general association of EBV viral load and urinary CXCL10. As non-invasive monitoring is implemented using biomarkers like CXCL10 in the clinic, attention will be needed to identify other uncommon, potential sources of CXCL10 elevation.

Cutaneous squamous cell carcinoma in an autosomal-recessive Adams-Oliver syndrome patient with a novel frameshift pathogenic variant in the EOGT gene

Aplasia cutis congenita (ACC) of the scalp and terminal transverse limb defects (TTLD) are the characteristic findings of Adams-Oliver syndrome (AOS). The variable clinical spectrum further includes cardiac, neurologic, renal, and ophthalmological findings. Associated genes in AOS are in the Notch and the CDC42/Rac1 signaling pathways. Both autosomal-dominant and autosomal-recessive inheritances have been reported, the latter with pathogenic variants in DOCK6 or EOGT. The EOGT-associated recessive type of AOS has been postulated to present a more favorable prognosis. We here report a 12-year-old girl from a refugee family of Iraq with consanguineous parents. She was born with a severe phenotype of AOS presenting a large ACC of the scalp with an underlying skull defect, which was often infected and inflamed. Afterward, additional ulceration developed. Furthermore, the girl showed microcephaly, TTLD on both hands and feet, and neurological findings: spastic paresis, epilepsy and suspicion of intellectual deficit. Molecular genetic analysis (next-generation sequencing) revealed a novel frameshift mutation in the EOGT gene in Exon 13 in homozygous constellation: c.1013dupA p.(Asn338Lysfs*24). A biopsy within an ulceration at the scalp ACC showed a cutaneous squamous cell carcinoma (cSCC) with local invasive growth into the dura, the meninges, and the cortex. Treatment including surgical resection and focal irradiation was not curative and the girl deceased 6 months after initial diagnosis. This report on a patient with AOS and an autosomal-recessive EOGT gene variant dying of a local aggressive cSCC at an ACC lesion shows that close monitoring of ACC is essential.

Synergistic effects of rare variants of ARHGAP31 and FBLN1 in vitro in terminal transverse limb defects

Background: Aplasia cutis congenita (ACC) and terminal transverse limb defects (TTLDs) are the most common features of Adams-Oliver syndrome (AOS). ARHGAP31 is one of the causative genes for autosomal dominant forms of AOS, meanwhile its variants may only cause isolated TTLD. Here, we report a proband presented with apparent TTLD but not ACC.

Methods: Whole exome sequencing (WES) and Sanger sequencing were applied to identify causative genes. Expression vectors were constructed for transfections in mammalian cell cultures followed by biochemical and functional analysis including immunoblotting, immunofluorescence staining, and cell counting kit-8 assay.

Results: WES and Sanger sequencing suggested that the proband inherited rare ARHGAP31 variant [c.2623G > A (p.Glu875Lys)] and a rare FBLN1 variant [c.1649G > A (p.Arg550His)] from one of her asymptomatic parents, respectively. Given FBLN1 variation has also been linked to syndactyly, we suspected that the two genes together contributed to the TTLD phenotype and explored their possible roles in vitro. Mutant FBLN1 showed reduced expression resulted from impaired protein stability, whereas ARHGAP31 protein expression was unaltered by mutation. Functional assays showed that only in the co-transfected group of two mutants cell viability was decreased, cell proliferation was impaired, and apoptosis was activated. Cdc42 activity was declined by both ARHGAP31 mutation and FBLN1 mutation alone, and the two together. Furthermore, the MAPK/ERK pathway was only activated by two mutants co-transfected group compared with two wild-type transfections.

Conclusion: We report a case carrying two rare variants of limb defects associated genes, ARHGAP31 and FBLN1, and provide in vitro evidence that synergistic disruption of cellular functions attributed by the two mutants may potentiate the penetrance of clinical manifestations, expanding our knowledge of clinical complexity of causal gene interactions in TTLD and other genetic disorders.

A Drosophila Su(H) model of Adams-Oliver Syndrome reveals cofactor titration as a mechanism underlying developmental defects

Notch signaling is a conserved pathway that converts extracellular receptor-ligand interactions into changes in gene expression via a single transcription factor (CBF1/RBPJ in mammals; Su(H) in Drosophila). In humans, RBPJ variants have been linked to Adams-Oliver syndrome (AOS), a rare autosomal dominant disorder characterized by scalp, cranium, and limb defects. Here, we found that a previously described Drosophila Su(H) allele encodes a missense mutation that alters an analogous residue found in an AOS-associated RBPJ variant. Importantly, genetic studies support a model that heterozygous Drosophila with the AOS-like Su(H) allele behave in an opposing manner to heterozygous flies with a Su(H) null allele, due to a dominant activity of sequestering either the Notch co-activator or the antagonistic Hairless co-repressor. Consistent with this model, AOS-like Su(H) and Rbpj variants have decreased DNA binding activity compared to wild type proteins, but these variants do not significantly alter protein binding to the Notch co-activator or the fly and mammalian co-repressors, respectively. Taken together, these data suggest a cofactor sequestration mechanism underlies AOS phenotypes associated with RBPJ variants, whereby the AOS-associated RBPJ allele encodes a protein with compromised DNA binding activity that retains cofactor binding, resulting in Notch target gene dysregulation.

Adams-Oliver Syndrome (AOS) is a rare disease defined by missing skin/skull tissue, limb malformations, and cardiovascular abnormalities. Human genetic studies have revealed that ~40% of AOS patients inherit dominant mutations within specific genes in the Notch signaling pathway. Notch signaling is a highly conserved cell-to-cell communication pathway found in all metazoans and plays crucial roles during embryogenesis and tissue homeostasis in organisms from Drosophila (fruit-flies) to mammals. The Notch receptor converts cell-to-cell interactions into a Notch signal that enters the nucleus and activates target genes by binding to a highly conserved transcription factor. Here, we took advantage of the unexpected finding that a previously described dominant allele in the Drosophila Notch pathway transcription factor contains a missense variant in an analogous residue found in a family with AOS. Using this novel animal model of AOS along with biochemical DNA binding, protein-protein interaction, and transcriptional reporter assays, we found that this transcription factor variant selectively compromises DNA binding but not binding to the Notch signal nor binding to other proteins in the Notch pathway. Taken together with prior human genetic studies, these data suggest AOS phenotypes associated with variants in the Notch pathway transcription factor are caused by a dominant mechanism that sequesters the Notch signal, leading to Notch target gene dysregulation.

Molecular genetics of pulmonary hypertension in children

Until recently, the molecular aetiology of paediatric pulmonary hypertension (PH) was relatively poorly understood. While the TGF-β/BMP pathway was recognised as central to disease progression, genetic analyses in children were largely confined to targeted screening of risk genes in small cohorts, with clinical management extrapolated from adult data. In recent years, next-generation sequencing has highlighted notable differences in the genetic architecture underlying childhood-onset cases, with a higher genetic burden in children partly explained by comorbidities such as congenital heart disease. Here, we review recent genetic advances in paediatric PH and highlight important risk factors such as dysregulation of the transcription factors SOX17 and TBX4. Given the poorer prognosis in paediatric cases, molecular diagnosis offers a vital tool to enhance clinical care of children with PH.

Adams-Oliver Syndrome: Vestigial Tail and Genetics Update

Adams-Oliver syndrome is a well-recognized autosomal dominant disorder for which mutations in six genes are etiologic, but account for only one-third of the cases. We report a patient with two genetic disorders; Adams-Oliver and Xp22.33 deletion syndromes, as well as a vestigial pseudotail. The presence of a pseudotail has not previously been reported in either of these genetic conditions. Absence of a molecular etiology underlying Adams-Oliver syndrome confirms that there are additional genetic causes to be identified.

Trichorhinophalangeal syndrome type II associated with aplasia cutis congenita in a neonate

Aplasia cutis congenita (ACC) was diagnosed in a newborn with dysmorphic facial features, oligodactyly of the bilateral feet, and hip instability. The neonate's clinical abnormalities in addition to genetic testing confirmed a diagnosis of trichorhinophalangeal syndrome (TRPS) type II. The possibility of concurrent Adams-Oliver syndrome (AOS) is raised.

Functional Studies of Genetic Variants Associated with Human Diseases in Notch Signaling-Related Genes Using Drosophila

Rare variants in the many genes related to Notch signaling cause diverse Mendelian diseases that affect myriad organ systems. In addition, genome- and exome-wide association studies have linked common and rare variants in Notch-related genes to common diseases and phenotypic traits. Moreover, somatic mutations in these genes have been observed in many types of cancer, some of which are classified as oncogenic and others as tumor suppressive. While functional characterization of some of these variants has been performed through experimental studies, the number of "variants of unknown significance" identified in patients with diverse conditions keeps increasing as high-throughput sequencing technologies become more commonly used in the clinic. Furthermore, as disease gene discovery efforts identify rare variants in human genes that have yet to be linked to a disease, the demand for functional characterization of variants in these "genes of unknown significance" continues to increase. In this chapter, we describe a workflow to functionally characterize a rare variant in a Notch signaling related gene that was found to be associated with late-onset Alzheimer's disease. This pipeline involves informatic analysis of the variant of interest using diverse human and model organism databases, followed by in vivo experiments in the fruit fly Drosophila melanogaster. The protocol described here can be used to study variants that affect amino acids that are not conserved between human and fly. By "humanizing" the almondex gene in Drosophila with mutant alleles and heterologous genomic rescue constructs, a missense variant in TM2D3 (TM2 Domain Containing 3) was shown to be functionally damaging. This, and similar approaches, greatly facilitate functional interpretations of genetic variants in the human genome and propel personalized medicine.

Overexpression of DOCK6 in oral squamous cell cancer promotes cellular migration and invasion and is associated with poor prognosis

OBJECTIVE

We aimed to identify the role of DOCK6 in oral squamous cell cancer (OSCC) in this study.

DESIGN

DOCK6 expression in OSCC was analyzed using TCGA and GEO datasets and was verified by quantitative real-time PCR, Western blotting, and immunohistochemistry. Statistical analyses were performed to evaluate the relationships between DOCK6 expression and the clinicopathological characteristics of OSCC patients. Wound healing and Transwell assays were performed to assess OSCC cell migration and invasion, respectively. STRING and GO analyses and gene set enrichment analysis were used to identify DOCK6-interacting proteins, their functions and their potential pathways.

RESULTS

DOCK6 was significantly upregulated at both the mRNA and protein levels in OSCC tissues (all P < 0.05). DOCK6 levels were positively correlated with age (P < 0.05), lymph node metastasis status (P < 0.001), clinical stage (P < 0.001), differentiation (P < 0.05), and poor clinical outcome (P < 0.05) in OSCC patients. Furthermore, univariate and multivariate analyses revealed that high DOCK6 expression (P < 0.01) and clinical stage III-IV (P < 0.05) might serve as independent prognostic factors for OSCC patients. Functionally, DOCK6 silencing significantly suppressed OSCC cell migration and invasion (all P < 0.05). Ten proteins that interact with DOCK6, more than ten functions related to cancer, and more than six pathways related to DOCK6 in OSCC were identified via bioinformatic methods.

CONCLUSION

DOCK6 is upregulated in OSCC, is associated with a poor prognosis in OSCC patients and increases OSCC cells migration and invasion. These findings suggest that DOCK6 may be a potential therapeutic target with prognostic implication in patients with OSCC.

Murine Model of Cardiac Defects Observed in Adams-Oliver Syndrome Driven by Delta-Like Ligand-4 Haploinsufficiency

Heterozygous loss-of-function mutation in Delta-like ligand-4 (Dll4) is an important cause of Adams-Oliver syndrome (AOS). Cardiac defects, in particular outflow tract (OFT) alignment defects, are observed in about one-fourth of patients with this syndrome. The mechanism underlying this genotype-phenotype correlation has not yet been established. Dll4-mediated Notch signaling is known to play a crucial role in second heart field (SHF) progenitor cell proliferation. We hypothesized that the depletion of the SHF progenitor pool of cells due to partial loss of Dll4 is responsible for the OFT alignment defects seen in AOS. To demonstrate this, we studied Dll4 expression by murine SHF progenitor cells around E9.5, a crucial time-point in SHF biology. We used SHF-specific (Islet1-Cre) conditional knockout of Dll4 to bypass the early embryonic lethality seen in global Dll4 heterozygotes. Dll4-mediated Notch signaling is critically required for SHF proliferation such that Dll4 knockout results in a 33% reduction in proliferation and a fourfold increase in apoptosis in SHF cells, leading to a 56% decline in the size of the SHF progenitor pool. A reduction in SHF cells available for incorporation into the developing heart leads to underdevelopment of the SHF-derived right ventricle and OFT. Similar to the clinical syndrome, 32% of SHF-specific Dll4 heterozygotes demonstrate foreshortened and misaligned OFT, resulting in a double outlet right ventricle. Our murine model provides a molecular mechanism to explain the cardiac defects observed in AOS and establishes a novel clinical role for Dll4-mediated Notch signaling in SHF progenitor biology.

Signaling Pathways in Bone Development and Their Related Skeletal Dysplasia

Bone development is a tightly regulated process. Several integrated signaling pathways including HH, PTHrP, WNT, NOTCH, TGF-β, BMP, FGF and the transcription factors SOX9, RUNX2 and OSX are essential for proper skeletal development. Misregulation of these signaling pathways can cause a large spectrum of congenital conditions categorized as skeletal dysplasia. Since the signaling pathways involved in skeletal dysplasia interact at multiple levels and have a different role depending on the time of action (early or late in chondrogenesis and osteoblastogenesis), it is still difficult to precisely explain the physiopathological mechanisms of skeletal disorders. However, in recent years, significant progress has been made in elucidating the mechanisms of these signaling pathways and genotype–phenotype correlations have helped to elucidate their role in skeletogenesis. Here, we review the principal signaling pathways involved in bone development and their associated skeletal dysplasia.

Case report and review of literature of a rare congenital disorder: Adams-Oliver syndrome

BACKGROUND

Adams-Oliver syndrome is characterized by the combination of congenital scalp defects and terminal transverse limb defects. In some instances, cardiovascular malformations and orofacial malformations have been observed. Little is written with regards to the anesthetic management and airway concerns of patients with Adams-Oliver syndrome.

CASE PRESENTATION

A five-year-old female with Adams-Oliver syndrome presented for repeat lower extremity surgery. Airway exam was significant for dysmorphic features, such as hypertelorism, deviated jaw, and retrognathia. Video laryngoscope was utilized for intubation due to the patients retrognathic jaw, cranial deformities, and facial dysmorphism. A vein finder with ultrasound guidance was needed to place the peripheral intravenous line due to her history of difficult intravenous access. The patient was successfully intubated with slight cricoid pressure applied to direct the endotracheal tube smoothly. Surgery and recovery were both unremarkable.

CONCLUSIONS

Due to varying presentations of Adams-Oliver syndrome, anesthetic and airway management considerations should be carefully assessed prior to surgery. Anesthesiologists must take into consideration possible orofacial abnormalities that may make intubation difficult. Amniotic band syndrome and other limb defects could potentially impact intravenous access as well.

Identification of a novel genetic locus associated with immune mediated thrombotic thrombocytopenic purpura

Immune thrombotic thrombocytopenic purpura (iTTP) is an ultra-rare, life-threatening disorder, mediated through severe ADAMTS13 deficiency causing multi-system micro-thrombi formation, and has specific human leukocyte antigen associations. We undertook a large genome-wide association study to investigate additional genetically distinct associations in iTTP. We compared two iTTP patient cohorts with controls, following standardized genome-wide quality control procedures for single-nucleotide polymorphisms and imputed HLA types. Associations were functionally investigated using expression quantitative trait loci (eQTL), and motif binding prediction software. Independent associations consistent with previous findings in iTTP were detected at the HLA locus and in addition a novel association was detected on chromosome 3 (rs9884090, P=5.22x10^-10, odds ratio 0.40) in the UK discovery cohort. Meta-analysis, including the French replication cohort, strengthened the associations. The haploblock containing rs9884090 is associated with reduced protein O-glycosyltransferase 1 (POGLUT1) expression (eQTL P<0.05), and functional annotation suggested a potential causative variant (rs71767581). This work implicates POGLUT1 in iTTP pathophysiology and suggests altered post-translational modification of its targets may influence disease susceptibility.

Bioinformatics and Functional Analyses Implicate Potential Roles for EOGT and L-fringe in Pancreatic Cancers

Notch signaling receptors, ligands, and their downstream target genes are dysregulated in pancreatic ductal adenocarcinoma (PDAC), suggesting a role of Notch signaling in pancreatic tumor development and progression. However, dysregulation of Notch signaling by post-translational modification of Notch receptors remains poorly understood. Here, we analyzed the Notch-modifying glycosyltransferase involved in the regulation of the ligand-dependent Notch signaling pathway. Bioinformatic analysis revealed that the expression of epidermal growth factor (EGF) domain-specific O-linked N-acetylglucosamine (EOGT) and Lunatic fringe (LFNG) positively correlates with a subset of Notch signaling genes in PDAC. The lack of EOGT or LFNG expression inhibited the proliferation and migration of Panc-1 cells, as observed by the inhibition of Notch activation. EOGT expression is significantly increased in the basal subtype, and low expression of both EOGT and LFNG predicts better overall survival in PDAC patients. These results imply potential roles for EOGT- and LFNG-dependent Notch signaling in PDAC.

Aplasia cutis congenita in a CDC42-related developmental phenotype

Cell division cycle 42 (CDC42) is a small Rho GTPase, which serves as a fundamental intracellular signal node regulating actin cytoskeletal dynamics and several other integral cellular processes. CDC42-associated disorders encompass a broad clinical spectrum including Takenouchi-Kosaki syndrome, autoinflammatory syndromes and neurodevelopmental phenotypes mimicking RASopathies. Dysregulation of CDC42 signaling by genetic defects in either DOCK6 or ARHGAP31 is also considered to play a role in the pathogenesis of Adams-Oliver syndrome (AOS). Here, we report a mother and her child carrying the previously reported pathogenic CDC42 variant c.511G>A (p.Glu171Lys). Both affected individuals presented with short stature, distinctive craniofacial features, pectus deformity as well as heart and eye anomalies, similar to the recently described Noonan syndrome-like phenotype associated with this variant. Remarkably, one of the patients additionally exhibited aplasia cutis congenita of the scalp. Multi-gene panel sequencing of the known AOS-causative genes and whole exome sequencing revealed no second pathogenic variant in any disease-associated gene explaining the aplasia cutis phenotype in our patient. This observation further expands the phenotypic spectrum of CDC42-associated disorders and underscores the role of CDC42 dysregulation in the pathogenesis of aplasia cutis congenita.

Diagnostic Clue in a Neonate with Amniotic Band Sequence

Amniotic band syndrome (ABS) is a set of congenital malformations that mainly affect the limbs and more rarely the skull, face, chest, and abdomen. Two main hypotheses have been proposed to explain the nature of the disorder: an intrinsic and extrinsic factor. We report a newborn with ABS presenting with several malformations involving both hands and foot. In this case, the malformative event localized at the hands and right foot without involvement of any other internal organs and is asymmetric which leads us to suppose the extrinsic factor as cause of the ABS.

Intracranial calcifications in childhood: Part 2

This article is the second of a two-part series on intracranial calcification in childhood. In Part 1, the authors discussed the main differences between physiological and pathological intracranial calcification. They also outlined histological intracranial calcification characteristics and how these can be detected across different neuroimaging modalities. Part 1 emphasized the importance of age at presentation and intracranial calcification location and proposed a comprehensive neuroimaging approach toward the differential diagnosis of the causes of intracranial calcification. Pathological intracranial calcification can be divided into infectious, congenital, endocrine/metabolic, vascular, and neoplastic. In Part 2, the chief focus is on discussing endocrine/metabolic, vascular, and neoplastic intracranial calcification etiologies of intracranial calcification. Endocrine/metabolic diseases causing intracranial calcification are mainly from parathyroid and thyroid dysfunction and inborn errors of metabolism, such as mitochondrial disorders (MELAS, or mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes; Kearns-Sayre; and Cockayne syndromes), interferonopathies (Aicardi-Goutières syndrome), and lysosomal disorders (Krabbe disease). Specific noninfectious causes of intracranial calcification that mimic TORCH (toxoplasmosis, other [syphilis, varicella-zoster, parvovirus B19], rubella, cytomegalovirus, and herpes) infections are known as pseudo-TORCH. Cavernous malformations, arteriovenous malformations, arteriovenous fistulas, and chronic venous hypertension are also known causes of intracranial calcification. Other vascular-related causes of intracranial calcification include early atherosclerosis presentation (children with risk factors such as hyperhomocysteinemia, familial hypercholesterolemia, and others), healed hematoma, radiotherapy treatment, old infarct, and disorders of the microvasculature such as COL4A1- and COL4A2-related diseases. Intracranial calcification is also seen in several pediatric brain tumors. Clinical and familial information such as age at presentation, maternal exposure to teratogens including viruses, and association with chromosomal abnormalities, pathogenic genes, and postnatal infections facilitates narrowing the differential diagnosis of the multiple causes of intracranial calcification.

Genetic Basis of Human Congenital Heart Disease

Congenital heart disease (CHD) is the most common major congenital anomaly with an incidence of ∼1% of live births and is a significant cause of birth defect-related mortality. The genetic mechanisms underlying the development of CHD are complex and remain incompletely understood. Known genetic causes include all classes of genetic variation including chromosomal aneuploidies, copy number variants, and rare and common single-nucleotide variants, which can be either de novo or inherited. Among patients with CHD, ∼8%-12% have a chromosomal abnormality or aneuploidy, between 3% and 25% have a copy number variation, and 3%-5% have a single-gene defect in an established CHD gene with higher likelihood of identifying a genetic cause in patients with nonisolated CHD. These genetic variants disrupt or alter genes that play an important role in normal cardiac development and in some cases have pleiotropic effects on other organs. This work reviews some of the most common genetic causes of CHD as well as what is currently known about the underlying mechanisms.

Pleiotropic Role of Notch Signaling in Human Skin Diseases

Notch signaling orchestrates the regulation of cell proliferation, differentiation, migration and apoptosis of epidermal cells by strictly interacting with other cellular pathways. Any disruption of Notch signaling, either due to direct mutations or to an aberrant regulation of genes involved in the signaling route, might lead to both hyper- or hypo-activation of Notch signaling molecules and of target genes, ultimately inducing the onset of skin diseases. The mechanisms through which Notch contributes to the pathogenesis of skin diseases are multiple and still not fully understood. So far, Notch signaling alterations have been reported for five human skin diseases, suggesting the involvement of Notch in their pathogenesis: Hidradenitis Suppurativa, Dowling Degos Disease, Adams-Oliver Syndrome, Psoriasis and Atopic Dermatitis. In this review, we aim at describing the role of Notch signaling in the skin, particularly focusing on the principal consequences associated with its alterations in these five human skin diseases, in order to reorganize the current knowledge and to identify potential cellular mechanisms in common between these pathologies.

A novel variant in DOCK6 gene associated with Adams-Oliver syndrome type 2

BACKGROUND

Adams-Oliver syndrome (AOS) is a rare, inherited multi-systemic malformation syndrome characterized by a combination of aplasia cutis congenita and transverse terminal limb defects along with variable involvement of the central nervous system, eyes, and cardiovascular system. AOS can be inherited as both autosomal-dominant and recessive traits. Pathogenic variants in the DOCK6, ARHGAP31, EOGT, RBPJ, DLL4, and NOTCH1 genes have been associated with AOS.

PURPOSE

To report a novel homozygous variant in the DOCK6 gene associated with Adams-Oliver syndrome type 2.

MATERIALS AND METHODS

Case report.

RESULTS

We report a case of a 4-month-old male who presented with microcephaly, global developmental delay, truncal hypotonia, and limb reduction defects. Ophthalmic examination revealed bilateral nystagmus and retinal detachment with mild cataractous changes in addition to retrolental plaque in the left eye. Next generation sequencing analysis identified a novel homozygous frameshift likely pathogenic variant (c.1269_1285dup (p.Arg429Glnfs*32)) in the DOCK6 gene. The constellation of the clinical findings and the genetic mutation were consistent with a diagnosis of AOS type 2.

CONCLUSION

The discovery of this new likely pathogenic variant enriches the genotypic spectrum of DOCK6 gene and contributes to genetic diagnosis and counseling of families with AOS. Neurologic and ocular findings appear to be consistent with AOS type 2 for which multidisciplinary clinical evaluation is crucial.

Novel In-Frame Deletion Mutation in NOTCH1 in a Chinese Sporadic Case of Adams-Oliver Syndrome

Adams-Oliver syndrome (AOS) is a rare hereditary disorder characterized by aplasia cutis congenita (ACC) and terminal transverse limb defects. The etiology of AOS has remained largely unknown, although mutations in the notch receptor 1 (NOTCH1) gene are most common genetic alteration associated with this disease. In this study, we aimed to identify the case of a 6-year-old boy, who presented with large ACC of the scalp and aortic valve stenosis, suggesting the possibility of AOS. Whole-exome sequencing identified a novel, de novo, in-frame deletion in the NOTCH1 gene (NOTCH1 c.1292_1294del, p.Asn431del) in the patient. The p.Asn431del variant was evaluated by several in silico analyses, which predicted that the mutant was likely to be pathogenic. In addition, molecular modeling with the PyMOL Molecular Graphics System suggested that the NOTCH1-N431del destabilizes calcium ion chelation, leading to decreased receptor-ligand binding efficiency. Quantitative reverse transcription PCR showed further significant downregulation of the Notch target genes, hes-related family bHLH transcription factor with YRPW motif 1 (HEY1) and hes family bHLH transcription factor 1 (HES1), suggesting that this mutation causes disease through dysregulation of the Notch signaling pathway. Our study provides evidence that the NOTCH1-N431del mutation is responsible for this case of AOS. To our knowledge, this is the first report of a patient with AOS caused by NOTCH1 mutation in Asia, and this information will be useful for providing the family with genetic counseling that can help to guide their future plans.

Treatment of a Large Skull Defect and Brain Herniation in a Newborn With Adams-Oliver Syndrome

Adams-Oliver syndrome (AOS) is a rare congenital disorder characterised by a wide variety of clinical expression ranging from the occurrence of aplasia cutis congenita (ACC), transverse limb defects, and cutis marmorata telangiectica to extensive lethal anomalies. In this article, we present the conservative and surgical management of a male newborn infant diagnosed with AOS. Surgical treatment included wound management, the removal of protruding brain, and treatment of cerebrospinal fluid (CSF) leakage. After spontaneous reepithelization of the wounds, conservative treatment was chosen instead of reconstruction with an occipital flap; this was continued until the total healing of the dermal defect after eight months, during which the patient was continuously treated with antibiotics. At 17 months, the child was in good physical condition with a three-month development delay in comparison with infants of his age and no evidence of neurological deficit.

Effects of Notch glycosylation on health and diseases

Notch signaling is an evolutionarily conserved signaling pathway and is essential for cell-fate specification in metazoans. Dysregulation of Notch signaling results in various human diseases, including cardiovascular defects and cancer. In 2000, Fringe, a known regulator of Notch signaling, was discovered as a Notch-modifying glycosyltransferase. Since then, glycosylation-a post-translational modification involving literal sugars-on the Notch extracellular domain has been noted as a critical mechanism for the regulation of Notch signaling. Additionally, the presence of diverse O-glycans decorating Notch receptors has been revealed in the extracellular domain epidermal growth factor-like (EGF) repeats. Here, we concisely summarize the recent studies in the human diseases associated with aberrant Notch glycosylation.

Genetics of Congenital Heart Disease

Congenital heart disease (CHD) is one of the most common birth defects. Studies in animal models and humans have indicated a genetic etiology for CHD. About 400 genes have been implicated in CHD, encompassing transcription factors, cell signaling molecules, and structural proteins that are important for heart development. Recent studies have shown genes encoding chromatin modifiers, cilia related proteins, and cilia-transduced cell signaling pathways play important roles in CHD pathogenesis. Elucidating the genetic etiology of CHD will help improve diagnosis and the development of new therapies to improve patient outcomes.

Genomic Divergence in Swedish Warmblood Horses Selected for Equestrian Disciplines

The equestrian sport horse Swedish Warmblood (SWB) originates from versatile cavalry horses. Most modern SWB breeders have specialized their breeding either towards show jumping or dressage disciplines. The aim of this study was to explore the genomic structure of SWB horses to evaluate the presence of genomic subpopulations, and to search for signatures of selection in subgroups of SWB with high or low breeding values (EBVs) for show jumping. We analyzed high density genotype information from 380 SWB horses born in the period 2010-2011, and used Principal Coordinates Analysis and Discriminant Analysis of Principal Components to detect population stratification. Fixation index and Cross Population Extended Haplotype Homozygosity scores were used to scan the genome for potential signatures of selection. In accordance with current breeding practice, this study highlights the development of two separate breed subpopulations with putative signatures of selection in eleven chromosomes. These regions involve genes with known function in, e.g., mentality, endogenous reward system, development of connective tissues and muscles, motor control, body growth and development. This study shows genetic divergence, due to specialization towards different disciplines in SWB horses. This latter evidence can be of interest for SWB and other horse studbooks encountering specialized breeding.

Expanding the phenotype in Adams-Oliver syndrome correlating with the genotype

RATIONALE

Adams-Oliver syndrome (AOS) is a genetic disorder characterized by the association of aplasia cutis congenita (ACC), terminal transverse limb defect (TTLD), congenital cardiac malformation (CCM), and minor features, such as cutaneous, neurological, and hepatic abnormalities (HAs). The aim of the study is to emphasize phenotype-genotype correlations in AOS.

METHODS

We studied 29 AOS patients. We recorded retrospectively detailed phenotype data, including clinical examination, biological analyses, and imaging. The molecular analysis was performed through whole exome sequencing (WES).

RESULTS

Twenty-nine patients (100%) presented with ACC, the principal inclusion criteria in the study. Seventeen of twenty-one (81%) had cutis marmorata telangiectasia congenita, 16/26 (62%) had TTLD, 14/23 (61%) had CCM, 7/20 (35%) had HAs, and 9/27 (33%) had neurological findings. WES was performed in 25 patients. Fourteen of twenty-five (56%) had alterations in the genes already described in AOS. CCM and HAs are particularly associated with the NOTCH1 genotype. TTLD is present in patients with DOCK6 and EOGT alterations. Neurological findings of variable degree were associated sometimes with DOCK6 and NOTCH1 rarely with EOGT.

CONCLUSION

AOS is characterized by a clinical and molecular variability. It appears that degrees of genotype-phenotype correlations exist for patients with identified pathogenic mutations, underlining the need to undertake a systematic but adjusted multidisciplinary assessment.

Genetic Basis for Congenital Heart Disease: Revisited: A Scientific Statement From the American Heart Association

This review provides an updated summary of the state of our knowledge of the genetic contributions to the pathogenesis of congenital heart disease. Since 2007, when the initial American Heart Association scientific statement on the genetic basis of congenital heart disease was published, new genomic techniques have become widely available that have dramatically changed our understanding of the causes of congenital heart disease and, clinically, have allowed more accurate definition of the pathogeneses of congenital heart disease in patients of all ages and even prenatally. Information is presented on new molecular testing techniques and their application to congenital heart disease, both isolated and associated with other congenital anomalies or syndromes. Recent advances in the understanding of copy number variants, syndromes, RASopathies, and heterotaxy/ciliopathies are provided. Insights into new research with congenital heart disease models, including genetically manipulated animals such as mice, chicks, and zebrafish, as well as human induced pluripotent stem cell-based approaches are provided to allow an understanding of how future research breakthroughs for congenital heart disease are likely to happen. It is anticipated that this review will provide a large range of health care-related personnel, including pediatric cardiologists, pediatricians, adult cardiologists, thoracic surgeons, obstetricians, geneticists, genetic counselors, and other related clinicians, timely information on the genetic aspects of congenital heart disease. The objective is to provide a comprehensive basis for interdisciplinary care for those with congenital heart disease.

Taking Systems Medicine to Heart

Systems medicine is a holistic approach to deciphering the complexity of human physiology in health and disease. In essence, a living body is constituted of networks of dynamically interacting units (molecules, cells, organs, etc) that underlie its collective functions. Declining resilience because of aging and other chronic environmental exposures drives the system to transition from a health state to a disease state; these transitions, triggered by acute perturbations or chronic disturbance, manifest as qualitative shifts in the interactions and dynamics of the disease-perturbed networks. Understanding health-to-disease transitions poses a high-dimensional nonlinear reconstruction problem that requires deep understanding of biology and innovation in study design, technology, and data analysis. With a focus on the principles of systems medicine, this Review discusses approaches for deciphering this biological complexity from a novel perspective, namely, understanding how disease-perturbed networks function; their study provides insights into fundamental disease mechanisms. The immediate goals for systems medicine are to identify early transitions to cardiovascular (and other chronic) diseases and to accelerate the translation of new preventive, diagnostic, or therapeutic targets into clinical practice, a critical step in the development of personalized, predictive, preventive, and participatory (P4) medicine.

Decoding the PTM-switchboard of Notch

The developmentally indispensable Notch pathway exhibits a high grade of pleiotropism in its biological output. Emerging evidence supports the notion of post-translational modifications (PTMs) as a modus operandi controlling dynamic fine-tuning of Notch activity. Although, the intricacy of Notch post-translational regulation, as well as how these modifications lead to multiples of divergent Notch phenotypes is still largely unknown, numerous studies show a correlation between the site of modification and the output. These include glycosylation of the extracellular domain of Notch modulating ligand binding, and phosphorylation of the PEST domain controlling half-life of the intracellular domain of Notch. Furthermore, several reports show that multiple PTMs can act in concert, or compete for the same sites to drive opposite outputs. However, further investigation of the complex PTM crosstalk is required for a complete understanding of the PTM-mediated Notch switchboard. In this review, we aim to provide a consistent and up-to-date summary of the currently known PTMs acting on the Notch signaling pathway, their functions in different contexts, as well as explore their implications in physiology and disease. Furthermore, we give an overview of the present state of PTM research methodology, and allude to a future with PTM-targeted Notch therapeutics.

Novel compound heterozygous mutations of the DOCK6 gene in a familial case of Adams-Oliver syndrome 2

INTRODUCTION

Adams-Oliver syndrome (AOS) is a rare developmental disorder characterized by the combination of aplasia cutis congenita of the scalp vertex and terminal transverse limb defects. DOCK6 (Dedicator of cytokinesis 6) is one of the six identified AOS genes.

METHODS

We performed targeted next-generation sequencing (NGS) of a child with an AOS phenotype. Sanger DNA sequencing further validated her lineal consanguinity. To explore the pathological features of the mutation, a minigene assay was used to investigate the effects of the mutation on splicing.

RESULTS

Two compound heterozygous DOCK6 mutations (c.4106+2T>C and c.3063 C>G (p.Y1021*)) were identified in this family, and both mutations have not been reported previously. Sanger DNA sequencing indicated that the mutations were inherited maternally and paternally, respectively. The results of the minigene assay showed that the c.4106+2T>C mutation resulted in aberrant splicing and caused a four-nucleotide insertion in the transcript and a premature stop codon.

CONCLUSIONS

Our findings expanded the number of reported cases of this rare disease and the mutation spectrum of DOCK6 mutations, which can serve as the basis for prenatal diagnosis and genetic counseling.

Ocular Manifestations of Cutis Marmorata Telangiectatica Congenita

PURPOSE

To describe the range of ocular manifestations in cutis marmorata telangectatica congenita (CMTC).

DESIGN

Multicenter, retrospective, nonconsecutive case series.

PARTICIPANTS

Patients with a diagnosis of CMTC referred for ophthalmologic evaluation between January 1, 2015, and December 31, 2018.

METHODS

Evaluation of ocular findings at presentation, systemic manifestations suggestive of a diagnosis of CMTC, genetic testing, and visual outcomes after treatment.

MAIN OUTCOME MEASURES

Visual acuity, findings on ophthalmoscopy, and results of fluorescein angiography.

RESULTS

Nine patients with CMTC diagnosed clinically based on stereotypical cutaneous vascular malformations were included. The median age at presentation was 8 weeks (range, 2 weeks-4 years). Six patients were female and 3 were male. Avascular retina was identified on dilated fundus examination, fluorescein angiography, or both in 11 eyes of 6 patients. Retinal neovascularization was present bilaterally in 2 patients at presentation. One patient demonstrated retinal venous tortuosity, and another patient showed mild straightening of nasal retinal vessels in both eyes. Two patients (2 eyes) demonstrated retinal detachment (RD). Both were managed surgically. One infant demonstrated RD, whereas the other child showed extensive neovascularization and later progressed to combined tractional-rhegmatogenous detachment. A unique constellation of lacy peripheral capillary anomalies with prominent terminal vascular bulbs was noted in 3 patients. Granular pigment abnormalities were noted in the macula in 5 patients. Two patients demonstrated glaucoma, 1 requiring surgical intervention. Two patients demonstrated features of Adams-Oliver syndrome, with genetic testing identifying a Notch1 mutation in 1 patient.

CONCLUSIONS

Retinal vascular abnormalities in CMTC may occur more frequently than recognized previously. Given the variability of ocular involvement and the potential for rapidly progressive retinal vascular abnormalities and development of RD, complete ophthalmologic evaluation including measurement of intraocular pressure, gonioscopy, dilated fundus examination, and fluorescein angiography is recommended in infants with suspected CMTC shortly after birth. The distinct pattern of lacy capillary anomalies with prominent terminal bulbs seen in CMTC has not been described in other syndromes of vascular dysgenesis. Therefore, ophthalmic examination may be a valuable method to distinguish CMTC from other disorders demonstrating similar dermatologic and systemic manifestations.

The UDP-Glycosyltransferase (UGT) Superfamily: New Members, New Functions, and Novel Paradigms

UDP-glycosyltransferases (UGTs) catalyze the covalent addition of sugars to a broad range of lipophilic molecules. This biotransformation plays a critical role in elimination of a broad range of exogenous chemicals and by-products of endogenous metabolism, and also controls the levels and distribution of many endogenous signaling molecules. In mammals, the superfamily comprises four families: UGT1, UGT2, UGT3, and UGT8. UGT1 and UGT2 enzymes have important roles in pharmacology and toxicology including contributing to interindividual differences in drug disposition as well as to cancer risk. These UGTs are highly expressed in organs of detoxification (e.g., liver, kidney, intestine) and can be induced by pathways that sense demand for detoxification and for modulation of endobiotic signaling molecules. The functions of the UGT3 and UGT8 family enzymes have only been characterized relatively recently; these enzymes show different UDP-sugar preferences to that of UGT1 and UGT2 enzymes, and to date, their contributions to drug metabolism appear to be relatively minor. This review summarizes and provides critical analysis of the current state of research into all four families of UGT enzymes. Key areas discussed include the roles of UGTs in drug metabolism, cancer risk, and regulation of signaling, as well as the transcriptional and posttranscriptional control of UGT expression and function. The latter part of this review provides an in-depth analysis of the known and predicted functions of UGT3 and UGT8 enzymes, focused on their likely roles in modulation of levels of endogenous signaling pathways.