Chromosome 2q31.2 Deletion Syndrome

A number sign (#) is used with this entry because it represents a contiguous gene deletion syndrome.

Clinical Features

Mencarelli et al. (2007) reported a 14-year-old boy with severe mental retardation, absence of speech, sleep disturbances, behavioral problems, and some dysmorphic features. He had 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 identified a 13-Mb interstitial deletion at chromosome 2q31.2-q32.3. The deletion was confirmed by quantitative PCR.

Monfort et al. (2008) reported a 14-year-old boy with moderate mental retardation associated with a de novo 3.3-Mb interstitial deletion at chromosome 2q31.2 spanning 16 genes. The authors identified a 0.5-Mb overlapping deleted region in their patient and the patient reported by Mencarelli et al. (2007), containing only the ZNF385B gene (612344). Monfort et al. (2008) noted that at birth their patient had neonatal hypertonia and fetal distress. Dysmorphic features included dysplastic ears, micrognathia, high-arched palate, and strabismus. He also had scoliosis, clinodactyly of the fifth finger, partial syndactyly of the second, third and fourth toes, and behavioral disorders including anxiety, anorexia, and head stereotypies. The authors noted that X-linked mental retardation has been associated with other zinc finger proteins, including ZNF41 (314995), ZNF81 (314998), and ZNF674 (300573). Monfort et al. (2008) suggested that loss-of-function mutations in zinc finger genes may play a common role in human cognitive processes.

Prontera et al. (2009) reported a 36-year-old man with a syndromic disorder associated with a de novo heterozygous 13.7-Mb deletion at chromosome 2q31.2-q32.3. He was born at 30 weeks' gestation with birth weight and length greater than the 90th percentile, and later showed developmental delay. At age 36 years, he had severe mental retardation and behavioral problems with occasional episodes of hyperactivity, chaotic movements, and aggression. Physical features included facial asymmetry, scaphocephaly, receding frontal bone with triangular anterior hair implantation, thick and coarse hair, prominent supraorbital ridges, thick eyebrows, synophrys, proptosis, long nose, thin nasal bridge, anteverted nares, high narrow palate, bifid uvula, small teeth, receding chin, low-set posteriorly rotated long ears with prominent antihelix, short neck, pectus excavatum, scoliosis, and macroorchidism. Other features included tapering fingers, sandal gap of the toes, and hypoplastic metatarsals. He had good muscular definition and strength, mainly in the legs and calves. Cytogenetic analysis also showed an apparently balanced de novo pericentric inversion of chromosome 8 (inv(8)(p11.2q21.2)) that was not thought to contribute to the phenotype. Prontera et al. (2009) noted the similarities to the patient reported by Mencarelli et al. (2007) who had a similar deletion of chromosome 2q31.2.