Cryptic Chromosomal Rearrangements in Children with Idiopathic Mental Retardation in the Czech Population

摘要

The aim of our study was to scan for cryptic rearrangements using the multiplex ligation probe amplification method in a cohort of 64 probands with mental retardation or developmental delays in combination with at least one of the following symptoms: hypotonia after birth, congenital anomalies, or face dys-morphisms; but without a positive cytogenetic finding. The study contributes to the knowledge of micro-deletion syndromes and helps disclose their natural phenotypic variability. Results: In total, 10 positives (16%) were detected, particularly 3 duplications (Xpter-p22.32; 17pll.2; 22qll) and 6 different deletions (Ip36; 7qll.23; 10pl5; 15qll-ql3; 17pll.2; 17pl3.3), 1 of these in 2 probands. Besides the well-characterized syndromes, less-often described rearrangements with ambiguous phenotype associations were also detected. Conclusions: Some rearrangements, particularly duplications, are associated with vague phenotypes; and their frequency could be underestimated.