Clinical and molecular characterization of a patient with a 2q31.2-32.3 deletion identified by array-CGH

Abstract

We report on a patient with a de novo interstitial deletion of the long arm of chromosome 2 involving bands 2q31.2-2q32.3. The patient shows severe mental retardation, absence of speech, sleep disturbances, behavioral problems, and some dysmorphic features. In particular, he presents with macrocephaly, high forehead, thick and coarse hair, thick eyebrows, synophrys, increased inner and outer canthal distance, bifid nasal tip, high palate, micrognathia, dysmorphic right ear, and long and tapering fingers. Array-CGH analysis allowed us to identify and characterize a 2q interstitial deletion of about 13 Mb, involving the segment between cytogenetic bands 2q31.2 and 2q32.3. The deletion was confirmed by quantitative PCR. We compare the phenotype of our patient with those already reported in literature. In particular, we discuss the similarities shared with two recently reported patients, studied by array-CGH, who show an overlapping deletion. The common clinical features are: long face, high forehead, abnormal teeth and ears, midface hypoplasia, high palate, micrognathia, transparent and thin skin, high frequency of inguinal hernia, severe development impairment, and behavioral problems. Some genes located in the deleted region may be good candidates for the neurological phenotype such as ZNF533 and MYO1B, which are both involved in neuronal function. Furthermore, the GLS gene could be a good candidate in generating the behavioral phenotype in the patient. In fact, it encodes for the major enzyme yielding glutamate from glutamine and it can be implicated in behavioral disturbances in which glutamate acts as a neurotransmitter.