ABSTRACT
OBJECTIVES: The phenotype for 10q22q23 duplication is diverse, ranging from intellectual disability and dysmorphism to normal development. Interpreting the clinical significance of the duplication identified in this region is difficult, especially in the prenatal setting. This study aimed to characterize the prenatal findings associated with this submicroscopic imbalance and discuss the dilemmas in predicting the phenotype of 10q22q23 duplications. METHODS: This is a retrospective study of three cases of 10q22q23 duplications diagnosed prenatally by chromosomal microarray analysis. Detailed pregnancy outcome and pediatric follow-up were documented. RESULTS: The genotypic and phenotypic features of the reported cases were discussed. 10q22q23 duplications are associated with an unpredictable and variable phenotypic outcome. Despite there was no phenotype found to be shared by 50% of the duplication cases, congenital heart defects, hypotelorism, and developmental delays including speech and motor delay seem to be more common. CONCLUSIONS: The phenotype of 10q22q23 duplication is highly variable prenatally and postnatally. Identification of additional affected individuals with similar duplications is needed to provide further insights into the pathogenesis of this microduplication. © 2016 John Wiley & Sons, Ltd.
Subject(s)
Chromosome Duplication/genetics , Chromosomes, Human, Pair 10/genetics , Phenotype , Prenatal Diagnosis/methods , Congenital Abnormalities/genetics , Developmental Disabilities/genetics , Diseases in Twins/genetics , Female , Fetal Growth Retardation/genetics , Genotype , Humans , In Situ Hybridization, Fluorescence , Microarray Analysis , Nuchal Translucency Measurement , Pregnancy , Pregnancy, Twin/genetics , Retrospective Studies , Ultrasonography, PrenatalABSTRACT
A genetic etiology for autism spectrum disorders (ASDs) was first suggested from twin studies reported in the 1970s. The identification of gene mutations in syndromic ASDs provided evidence to support a genetic cause of ASDs. More recently, genome-wide copy number variant and sequence analyses have uncovered a list of rare and highly penetrant copy number variants (CNVs) or single nucleotide variants (SNVs) associated with ASDs, which has strengthened the claim of a genetic etiology for ASDs. Findings from research studies in the genetics of ASD now support an important role for molecular diagnostics in the clinical genetics evaluation of ASDs. Various molecular diagnostic assays including single gene tests, targeted multiple gene panels and copy number analysis should all be considered in the clinical genetics evaluation of ASDs. Whole exome sequencing could also be considered in selected clinical cases. However, the challenge that remains is to determine the causal role of genetic variants identified through molecular testing. Variable expressivity, pleiotropic effects and incomplete penetrance associated with CNVs and SNVs also present significant challenges for genetic counseling and prenatal diagnosis.
