De novo 1Mb interstitial deletion of 8p22 in a patient with slight mental retardation and speech delay.

We report on a nine years old girl born after 41 weeks of normal gestation with psychomotor retardation, speech delay and minimal dysmorphic signs: antimongolic cut eyes, small mouth, short philtrum and hypertelorism. The use of the high-resolution Affymetrix Human Mapping GeneChip 250 K NspI array allowed the characterization of a de novo 1Mb deletion on the short arm (p22) of a chromosome 8. Molecular cytogenetic-FISH with BAC probes (RP11) confirmed the deletion. The deleted region includes part of the sarcoglycan zeta (SGCZ) gene, involved in the sarcoglycan complex formation, and the microRNA 383. The deletion described in our patient falls 319 Kb upstream of the Tumor Suppressor Candidate 3 (TUSC3) gene. In this chromosomal region, a limited number of cases of overlapping deletions, of variable extensions and characterized by heterogeneous clinical phenotype, have been reported. The deleted region described in our patient is the smallest among those so far described in this region.