Nonmosaic tetrasomy 15q25.2 → qter identified with SNP microarray in a patient with characteristic facial appearance and review of the literature

Emerging roles for the ADAMTS-like family of matricellular proteins in cardiovascular disease through regulation of the extracellular microenvironment

Dysregulation of the extracellular matrix (ECM) occurs widely across cardiovascular pathologies. Recent work has revealed important roles for the «a disintegrin-like and metalloprotease domain with thrombospondin-type 1 motifs like" (ADAMTSL) family of secreted glycoproteins in cardiovascular tissues during development and disease. Key insights in this regard have come from naturally occurring gene mutations in humans and animals that result in severe diseases with cardiovascular manifestations or aortopathies. Expression of ADAMTSL genes is greatly increased in the myocardium during heart failure. Genetically modified mice recapitulate phenotypes of patients with ADAMTSL mutations and demonstrate important functions in the ECM. The novel functions thus disclosed are intriguing because, while these proteins are neither structural, nor proteases like the related ADAMTS proteases, they appear to act as regulatory, i.e., matricellular proteins. Evidence from genetic variants, genetically engineered mouse mutants, and in vitro investigations have revealed regulatory functions of ADAMTSLs related to fibrillin microfibrils and growth factor signaling. Interestingly, the ability to regulate transforming growth factor (TGF)β signaling may be a shared characteristic of some ADAMTSLs. TGFβ signaling is important in cardiovascular development, health and disease and a central driver of ECM remodeling and cardiac fibrosis. New strategies to target dysregulated TGFβ signaling are warranted in aortopathies and cardiac fibrosis. With their emerging roles in cardiovascular tissues, the ADAMTSL proteins may provide causative genes, diagnostic biomarkers and novel treatment targets in cardiovascular disease. Here, we discuss the relevance of ADAMTSLs to cardiovascular medicine.

The Application of Optical Genome Mapping (OGM) in Severe Short Stature Caused by Duplication of 15q14q21.3

(1) Background: Optical genome mapping (OGM) is a novel approach to identifying genomic structural variations with high accuracy and resolution. We report a proband with severe short stature caused by 46, XY, der (16) ins (16;15) (q23; q21.3q14) that was detected by OGM combined with other tests and review the clinical features of patients with duplication within 15q14q21.3; (2) Methods: OGM, whole exon sequencing (WES), copy number variation sequencing (CNV-seq), and karyotyping were used; (3) Results: The proband was a 10.7-year-old boy with a complaint of severe short stature (-3.41SDS) and abnormal gait. He had growth hormone deficiency, lumbar lordosis, and epiphyseal dysplasia of both femurs. WES and CNV-seq showed a 17.27 Mb duplication of chromosome 15, and there was an insertion in chromosome 16 found by karyotyping. Furthermore, OGM revealed that duplication of 15q14q21.3 was inversely inserted into 16q23.1, resulting in two fusion genes. A total of fourteen patients carried the duplication of 15q14q21.3, with thirteen previously reported and one from our center, 42.9% of which were de novo. In addition, neurologic symptoms (71.4%,10/14) were the most common phenotypes; (4) Conclusions: OGM combined with other genetic methods can reveal the genetic etiology of patients with the clinical syndrome, presenting great potential for use in properly diagnosing in the genetic cause of the clinical syndrome.

ADAMTSL3 knock-out mice develop cardiac dysfunction and dilatation with increased TGFβ signalling after pressure overload

Heart failure is a major cause of morbidity and mortality worldwide, and can result from pressure overload, where cardiac remodelling is characterized by cardiomyocyte hypertrophy and death, fibrosis, and inflammation. In failing hearts, transforming growth factor (TGF)β drives cardiac fibroblast (CFB) to myofibroblast differentiation causing excessive extracellular matrix production and cardiac remodelling. New strategies to target pathological TGFβ signalling in heart failure are needed. Here we show that the secreted glycoprotein ADAMTSL3 regulates TGFβ in the heart. We found that Adamtsl3 knock-out mice develop exacerbated cardiac dysfunction and dilatation with increased mortality, and hearts show increased TGFβ activity and CFB activation after pressure overload by aortic banding. Further, ADAMTSL3 overexpression in cultured CFBs inhibits TGFβ signalling, myofibroblast differentiation and collagen synthesis, suggesting a cardioprotective role for ADAMTSL3 by regulating TGFβ activity and CFB phenotype. These results warrant future investigation of the potential beneficial effects of ADAMTSL3 in heart failure.

Clinical, cytogenetic and molecular analyses of a rare case with ring chromosome 15 and review of the literature

OBJECTIVE

Ring chromosome 15 [r (15)], accompanied by a series of clinical symptoms, is a rare genetic disease. The genotype and phenotypic diversity of patients with r (15) still needed further enrichment. In this study we present a rare case of mosaic ring chromosome 15 with facial anomalies and extremities slenderness.

CASE REPORT

This case involves a 30-year-old woman, unpregnancy within 6 years. Clinical examination of the patient only revealed facial anomalies and extremities slenderness. The result of routine G-band karyotyping was 46,XX,r(15)(p12q26.3)[53]/46,XX,r(15;15)(p11.2q26.3;p11.2q11.2)[28]/45,XX, -15[10]/46,XX,r(15;15)(p11q26.3;p11q26.3)[4]. SNP array was employed to investigate the genome copy number variations (CNVs). The result revealed that there was a micro-duplication of 2.0 Mb at 15q26.3(arr[ph19]15q26.3 (100,400,214- 102,429,112)×3). The duplicated chromosomal section encompassed genes including CHSY1, ALDHIA3, LRRK1, and INS1. We further compared to the cytogenetic characteristics and clinical symptoms of the patient with those already reported by reviewing the literature.

CONCLUSION

This report is especially helpful to supplement the phenotypic diversity of patients with r (15).

Prenatal diagnosis of partial monosomy 8p (8p23.2→pter) and partial trisomy 15q (15q21.2→qter) and incidental detection of a familial chromosome translocation of paternal origin in a pregnancy associated with increased nuchal translucency and an abnormal maternal serum screening result

OBJECTIVE

We present partial monosomy 8p (8p23.2→pter) and partial trisomy 15q (15q21.2→qter) and incidental detection of a familial chromosome translocation of paternal origin in a pregnancy associated with increased nuchal translucency (NT) and an abnormal maternal serum screening result.

CASE REPORT

A 29-year-old primigravid woman underwent chorionic villus sampling (CVS) at 13 weeks of gestation because of an increased NT thickness of 3.2 mm at 12 weeks of gestation and an abnormal maternal serum screening for Down syndrome result with a calculated risk of 1/29. Her husband was 33 years old, and there was no family history of congenital malformations. CVS revealed a derived chromosome 8 or der(8). Cytogenetic analysis of the parents revealed a karyotype of 46,XY,t(8;15)(p21.3;q13) in the father and a karyotype of 46,XX in the mother. The CVS result was 46,XY,der(8)t(8;15)(p21.3;q13)pat. The woman requested for amniocentesis at 16 weeks of gestation. Array comparative genomic hybridization (aCGH) analysis on the DNA extracted from uncultured amniocytes revealed a result of arr 8p23.3p23.2 (191,530-2,625,470) × 1.0, arr 15q21.2q26.3 (50,903,432-102,338,129) × 3.0 with a 2.434-Mb deletion of 8p23.3-p23.2 including DLGAP2, CLN8 and ARHGEF10, and a 51.435-Mb duplication of 15q21.2-q26.3 including CYP19A1 and IGF1R. Conventional cytogenetic analysis of cultured amniocytes revealed the result of 46,XY,der(8) t(8;15)(p23.2;q21.2)pat in the fetus. The pregnancy was subsequently terminated, and a malformed fetus was delivered with characteristic craniofacial dysmorphism.

CONCLUSION

Maternal serum screening and NT screening may incidentally detect familial unbalanced reciprocal translocations, and aCGH analysis is useful for a precise determination of the breakpoints of the translocation and the involvement of the related genes under such a circumstance.

Prenatal diagnosis of a pure 15q distal trisomy derived from a maternal pericentric inversion: A case report

Distal trisomy or duplication of 15q is a very rare chromosomal disorder; most of the previously reported cases were derived from unbalanced translocations involving chromosome 15 and another chromosome, whereas other mechanisms (e.g. duplication) have rarely been reported. We herein report a very rare prenatal case of a partial 15q trisomy, a 42.64-Mb duplication of 15q22.2-q26.3, arising from a maternal pericentric inversion of chromosome 15 (p11q22) that was not the result of an unbalanced translocation or duplication, and was not associated with concomitant partial monosomy. Fetal ultrasound revealed isolated thickened nuchal translucency at 12 weeks and multiple abnormalities in the second trimester, including early growth restriction, unilateral ventriculomegaly, narrow cavum septi pellucidi with hypoplasia of the corpus callosum, unilateral postaxial polydactyly, clenched hands and clubfoot with clawing of the toes, and a particular general dysplastic and hypotrophic aspect of the heart. The distinctive aspects of the present case may help to refine the phenotype associated with distal duplication 15q. To the best of our knowledge, this is the first report of a prenatal diagnosis with a 15q22.2-q26.3 duplication that did not result from an unbalanced translocation and did not have a concomitant monosomic component.

Prenatal diagnosis of a de novo tetrasomy 15q24.3-25.3: Case report and literature review

BACKGROUND

Terminal duplication on chromosome 15q is a rare chromosomal variation. Affected individuals show similar features such as growth dysplasia or the development of frontal bossing, body deformities, facial abnormalities, and genitourinary or cardiovascular disorders. However, it is not yet clear whether such 15q repeats lead to identifiable patterns of clinical abnormalities. Therefore, the purpose of this study was to analyze the prenatal diagnostic results and clinical manifestations of a fetus with 15q duplication and to summarize the literature.

METHODS

The case was a fetus at 28 weeks of gestation. The risk of Down syndrome from second-trimester screening was 1/140. Prenatal ultrasound and amniocentesis were performed, and chromosomal microarray analysis (CMA) was used for genetic analysis.

RESULTS

The fetus had abnormal clinical features, including intracardiac echogenic focus in the left ventricle, an aberrant right subclavian artery, and growth delay. The fetal chromosomal karyotype was 46,XX,15q?,12q?,21pstk+, and CMA revealed a 10.163 Mb duplication at 15q24.3-q25.3. The couple chose to terminate the pregnancy after careful consideration.

CONCLUSIONS

The combination and rational application of cytogenetics technology and molecular genetics technology such as CMA will open up the field of clinical application and provide useful genetic counseling for parents of fetuses carrying such chromosomal duplications.

Genomic inversions and GOLGA core duplicons underlie disease instability at the 15q25 locus

Human chromosome 15q25 is involved in several disease-associated structural rearrangements, including microdeletions and chromosomal markers with inverted duplications. Using comparative fluorescence in situ hybridization, strand-sequencing, single-molecule, real-time sequencing and Bionano optical mapping analyses, we investigated the organization of the 15q25 region in human and nonhuman primates. We found that two independent inversions occurred in this region after the fission event that gave rise to phylogenetic chromosomes XIV and XV in humans and great apes. One of these inversions is still polymorphic in the human population today and may confer differential susceptibility to 15q25 microdeletions and inverted duplications. The inversion breakpoints map within segmental duplications containing core duplicons of the GOLGA gene family and correspond to the site of an ancestral centromere, which became inactivated about 25 million years ago. The inactivation of this centromere likely released segmental duplications from recombination repression typical of centromeric regions. We hypothesize that this increased the frequency of ectopic recombination creating a hotspot of hominid inversions where dispersed GOLGA core elements now predispose this region to recurrent genomic rearrangements associated with disease.

Prenatal diagnosis: the clinical usefulness of array comparative genomic hybridization

Background

Array comparative genomic hybridization (aCGH) has been replacing karyotype in neurodevelopment diseases or intellectual disability cases. Regarding prenatal diagnosis (PND) karyotyping is still the criterion standard technique; nevertheless, the application of aCGH in this field has been increasing dramatically and some groups recommended it as the first-tier prenatal genetic test in cases of fetal ultrasound abnormalities. Despite aCGH greater resolution, the detection of variants of unknown significance (VOUS) is not desirable, so it's need some reflexion before generalized application on PND.

Objective

The aim of this study was to analyze the prevalence and type of copy number variants (CNVs) detected in the 55 PND samples collected from pregnancies with indication to perform aCGH.

Methods

aCGH was performed using Agilent 4 × 180K microarrays and results were analyzed using CytoGenomics software.

Results and conclusion

Eight (14.5%) cases had pathogenic or likely pathogenic CNVs. VOUS were found in 21.8% of the cases, but this frequency could be minimized if only large CNVs above 1 million base pairs that are outside the clinically curated targeted regions were considered.

Identification of De Novo and Rare Inherited Copy Number Variants in Children with Syndromic Congenital Heart Defects

Congenital heart defects (CHDs) are the most common birth defects in neonatal life. CHDs could be presented as isolated defects or associated with developmental delay (DD) and/or other congenital malformations. A small proportion of cardiac defects are caused by chromosomal abnormalities or single gene defects; however, in a large proportion of cases no genetic diagnosis could be achieved by clinical examination and conventional genetic analysis. The development of genome wide array-Comparative Genomic Hybridization technique (array-CGH) allowed for the detection of cryptic chromosomal imbalances and pathogenic copy number variants (CNVs) not detected by conventional techniques. We investigated 94 patients having CHDs associated with other malformations and/or DD. Clinical examination and Echocardiography was done to all patients to evaluate the type of CHD. To investigate for genome defects we applied high-density array-CGH 2 × 400K (41 patients) and CGH/SNP microarray 2 × 400K (Agilent) for 53 patients. Confirmation of results was done using Fluorescent in situ hybridization (FISH) or qPCR techniques in certain cases. Chromosomal abnormalities such as trisomy 18, 13, 21, microdeletions: del22q11.2, del7q11.23, del18 (p11.32; p11.21), tetrasomy 18p, trisomy 9p, del11q24-q25, add 15p, add(18)(q21.3), and der 9, 15 (q34.2; q11.2) were detected in 21/94 patients (22%) using both conventional cytogenetics methods and array-CGH technique. Cryptic chromosomal anomalies and pathogenic variants were detected in 15/73 (20.5%) cases. CNVs were observed in a large proportion of the studied samples (27/56) (48%). Clustering of variants was observed in chromosome 1p36, 1p21.1, 2q37, 3q29, 5p15, 7p22.3, 8p23, 11p15.5, 14q11.2, 15q11.2, 16p13.3, 16p11.2, 18p11, 21q22, and 22q11.2. CGH/SNP array could detect loss of heterozygosity (LOH) in different chromosomal loci in 10/25 patients. Array-CGH technique allowed for detection of cryptic chromosomal imbalances that could not be detected by conventional cytogenetics methods. CHDs associated with DD/congenital malformations presented with a relatively high rate of cryptic chromosomal abnormalities. Clustering of CNVs in certain genome loci needs further analysis to identify candidate genes that may provide clues for understanding the molecular pathway of cardiac development.

Chromosome 15 structural abnormalities: effect on IGF1R gene expression and function

Insulin-like growth factor 1 receptor (IGF1R), mapping on the 15q26.3 chromosome, is required for normal embryonic and postnatal growth. The aim of the present study was to evaluate the IGF1R gene expression and function in three unrelated patients with chromosome 15 structural abnormalities. We report two male patients with the smallest 15q26.3 chromosome duplication described so far, and a female patient with ring chromosome 15 syndrome. Patient one, with a 568 kb pure duplication, had overgrowth, developmental delay, mental and psychomotor retardation, obesity, cryptorchidism, borderline low testis volume, severe oligoasthenoteratozoospermia and gynecomastia. We found a 1.8-fold increase in the IGF1R mRNA and a 1.3-fold increase in the IGF1R protein expression (P < 0.05). Patient two, with a 650 kb impure duplication, showed overgrowth, developmental delay, mild mental retardation, precocious puberty, low testicular volume and severe oligoasthenoteratozoospermia. The IGF1R mRNA and protein expression was similar to that of the control. Patient three, with a 46,XX r(15) (p10q26.2) karyotype, displayed intrauterine growth retardation, developmental delay, mental and psychomotor retardation. We found a <0.5-fold decrease in the IGF1R mRNA expression and an undetectable IGF1R activity. After reviewing the previously 96 published cases of chromosome 15q duplication, we found that neurological disorders, congenital cardiac defects, typical facial traits and gonadal abnormalities are the prominent features in patients with chromosome 15q duplication. Interestingly, patients with 15q deletion syndrome display similar features. We speculate that both the increased and decreased IGF1R gene expression may play a role in the etiology of neurological and gonadal disorders.