Journal of Genetic Syndromes & Gene Therapy
Open Access

Abstract

A Mosaic Ring Chromosome 21 in a Patient with Mild Intellectual Disability not Evidenced by Array-Cgh

Lucia Militti, Melissa Alfonsi, Chiara Palka, Alessandra Soranno, Giuseppe Calabrese, Giandomenico Palka, Robert T Zori and Paolo Guanciali-Franchi

We report a case of a two year-old girl with persistent thrombocytopenia, syndactyly, and mild psychomotor delay with speech delay. Proband chromosomal analysis from peripheral blood detected a mosaicism with two cell lines: the first with a ring chromosome 21 46,XX,r (21) (88%), and the second 45,XX,-21 (12%). In uncultured cells the level of mosaicism was 15% for the 46,XX,r(21) cell line and 85% for the 45,XX,-21 cell line. A different level of mosaicism was detected on buccal smear cells with a r(21) in 94%, and monosomy 21 in 6% of cells. The findings in the different cell lines are consistent with loss of the ring chromosome in the blood line.