Constitutional chromosome 16q mosaicism: inheritance and phenotypic effects

Abstract

Partial monosomies of chromosome 16q are rare. Here, we report a boy showed various aberrations in the q22.1→qter region of chromosome 16 and some important clinical features. The patient presented low IQ, delayed speech, delayed psychomotor development, late walking, clapping hands in case of excitement, deficiency in social adjustment and incompatibility with peers. Standard cytogenetic analysis was performed to patient and his family. Cytogenetic analysis results showed deletions, breaks and fragilities in the q22.1 region in one of chromosome 16. Analyzed cells of patient and his father showed 38% and 26% structural aberrations, respectively. Aberrations were inherited from an apparently normal father. The comparison of the present case to other 16q22.1→qter monosomies contributed to narrow down the critical region for delayed speech and full undeveloped fine motor skills in the 16q22.1→qter deletion syndrome. We showed that 16q deletions are confined to the phenotypic features such as delayed speech, full undeveloped fine motor skills.