2q37.3 Deletion Syndrome: Two Cases with Highly Distinctive Facial Phenotype, Discordant Association with Schizophrenic Psychosis, and Shared Deletion Breakpoint Region on 2q37.3.

2q37.3 deletion syndrome belongs to the chromosomal 2q37 deletion spectrum which clinically resembles Albright hereditary osteodystrophy (AHO) syndrome. It is is mainly characterized by short stature, obesity, round face, brachydactyly type E, intellectual disability, behavioral problems, and variable intellectual deficits. Different from classical AHO syndrome, patients with 2q37 deletion syndrome lack renal parathyroid hormone resistance (pseudohypoparathyroidism) and soft tissue ossification. So far, deletion mapping or molecular breakpoint analyses of 2q37 have been performed in only few patients. Here, we report on 2 patients with 2q37.3 deletion syndrome. In both patients the breakpoint of the 5.5-Mb terminal microdeletion could be narrowed down to the same ∼ 200-kb interval on 2q37.3 by BAC-FISH and/or array-CGH. Flanking low-copy repeats may indicate a classical microdeletion syndrome genesis for the 2q37.3 microdeletion subgroup. Clinical evaluation revealed intellectual deficits and type E brachydactyly typical for classical AHO syndrome together with distinctive facial dysmorphisms not present in the former. Furthermore, one patient presented with schizophrenic psychosis, an observation that would be in accordance with previous reports about an association between schizophrenia susceptibility and an unknown gene within the chromosomal region 2q37.