ATR-16 Due to a De Novo Complex Rearrangement of Chromosome 16

Abstract

We describe a child with ATR-16 [α-thalassemia (thal)/mental retardation], who was referred forgenetic evaluation because of minor anomalies and developmental delay. Cytogenetic analysisdemonstrated a de novo complex rearrangement of chromosome 16. Fluorescence in situ hybridization(FISH) analysis, using chromosome 16 subtelomeric probes, showed that this patient had a deletion ofthe distal short arm of chromosome 16 that contains the α-globin genes and a duplication of 16q.Analysis of the α-globin locus by Southern blot showed a half normal dose of the α-globin gene.Microsatellite marker studies revealed that the duplicated 16q region was maternal in origin.Hematological studies revealed anemia, hypochromia and occasional cells with Hb H inclusion bodies. Ahematological screening for α-thal should be considered in patients with mild developmental delay and asuggestive phenotype of ATR-16 with microcytic hypochromic anemia and normal iron status. The stellatepattern of the iris, a new finding in our patient, may contribute to a better clinical delineation ofboth syndromes, ATR-16 and/or duplication of 16qter.