Genotype-Phenotype Correlation in Four 15q24 Deleted Patients Identified by Array-CGH
ABSTRACT Microdeletion 15q24 is an emerging syndrome recently described, mainly due to increased use of array-CGH. Clinical features associate mild to moderate developmental delay, typical facial characteristics (high forehead and frontal hairline, broad eyebrows, downslanting palpebral features, long philtrum), hands (particularly proximal implanted thumbs) and genital anomalies (micropenis, hypospadias). We report here on four de novo cases having 2.5-6.1 Mb deletions involving 15q24: one 15q23q24.2 (Patient 1) and three 15q24.1q24.2 deletions (Patients 2-4). We correlate phenotype to genotype according to molecular boundaries of these deletions. Since bilateral iris coloboma and severe ano-rectal malformation were only present in Patient 1, we could link these anomalies to haploinsufficiency of 15q23 genes. Neither hypospadias nor micropenis were present in Patient 3 bearing the smallest deletion, therefore we could define 500 kb 15q24.1 region linked to these anomalies.
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- "Other CGH arrays revealed a novel recurrent 15q24 microdeletion syndrome with the deletions being between 1.7 and 3.9 Mb in size. The syndrome is characterized, amongst other features, by genital anomalies in male, including micropenis and hypospadias (Sharp et al. 2007; Andrieux et al. 2009), but the causative genes have not been identified. "
ABSTRACT: Disorders of sex development (DSD) are congenital conditions in which the development of chromosomal, gonadal, or anatomical sex is atypical. Many of the genes required for gonad development have been identified by analysis of DSD patients. However, the use of knockout and transgenic mouse strains have contributed enormously to the study of gonad gene function and interactions within the development network. Although the genetic basis of mammalian sex determination and differentiation has advanced considerably in recent years, a majority of 46,XY gonadal dysgenesis patients still cannot be provided with an accurate diagnosis. Some of these unexplained DSD cases may be due to mutations in novel DSD genes or genomic rearrangements affecting regulatory regions that lead to atypical gene expression. Here, we review our current knowledge of mammalian sex determination drawing on insights from human DSD patients and mouse models.Chromosome Research 01/2012; 20(1):215-38. DOI:10.1007/s10577-012-9274-3 · 2.69 Impact Factor
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ABSTRACT: Although the genetic basis of human sexual determination and differentiation has advanced considerably in recent years, the fact remains that in most subjects with disorders of sex development (DSD) the underlying genetic cause is unknown. Where pathogenic mutations have been identified, the phenotype can be highly variable, even within families, suggesting that other genetic variants are influencing the expression of the phenotype. This situation is likely to change, as more powerful and affordable tools become widely available for detailed genetic analyses. Here, we describe recent advances in comparative genomic hybridisation, sequencing by hybridisation and next generation sequencing, and we describe how these technologies will have an impact on our understanding of the genetic causes of DSD.Sexual Development 09/2010; 4(4-5):213-24. DOI:10.1159/000314917 · 1.76 Impact Factor
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ABSTRACT: To investigate the potential influence of additional copy number variants in patients with 15q24 rearrangements and the possible underlying mechanisms for these rearrangements. Oligonucleotide-based chromosomal microarray analyses were performed, and the results were subsequently confirmed by fluorescence in situ hybridization analyses. Long-range polymerase chain reaction amplification and DNA sequencing analysis were used for breakpoint junction sequencing. We describe a 15-year-old boy with cognitive impairment and dysmorphic features with deletions in 15q24 and 3q21, a 2-month-old female infant with growth deficiency, heterotaxy, cardiovascular malformations, intestinal atresia, and duplications in 15q24 and 16q22, and a 3.5-year-old boy with developmental delay, microcephaly, and dysmorphic features, with duplications in 15q24 and 2q36.3q37.1. Breakpoint sequencing for the 15q24 deletion in the first patient revealed microhomology and suggested the underlying mechanism of either nonhomologous end joining or fork stalling and template switching/microhomology-mediated break-induced replication. The three described patients with 15q24 rearrangements have copy number variants at other loci and exhibit additional clinical features with a more severe phenotype than that observed in previously reported patients with isolated 15q24 rearrangements, suggesting that the genomic mutational load may contribute to the phenotypic severity and variability in patients with 15q24 rearrangements.Genetics in medicine: official journal of the American College of Medical Genetics 09/2010; 12(9):573-86. DOI:10.1097/GIM.0b013e3181eb9b4a · 6.44 Impact Factor