A rare case of uniparental isodisomy of chromosome 7 without phenotypic anomalies.

Uniparental disomy (UPD) is a well-known epigenomic anomaly with both copies of a homologous pair of chromosomes (or part thereof) inherited from the same parent. Unlike numerical or structural chromosomal aberrations, UPD has no effects on chromosome number or structure, thereby escaping cytogenetic detection. However, UPD detection could be performed by the microsatellite analysis or SNP-based chromosomal microarray analysis (CMA) method. UPD may cause diseases in humans by disrupting normal allelic expression of genes undergoing genomic imprinting, homozygosity in case of autosomal recessive traits, or mosaic aneuploidy. Here we present the first case of parental UPD for chromosome 7 with a normal phenotype.