Atypical autism in a boy with double duplication of 22q11.2: implications of increasing dosage

Neurodevelopmental functioning in probands and non-proband carriers of 22q11.2 microduplication

Microduplication of the LCR22-A to LCR22-D region on chromosome 22q11.2 is a recurrent copy number variant found in clinical populations undergoing chromosomal microarray, and at lower frequency in controls. Often inherited, there is limited data on intellectual (IQ) and psychological functioning, particularly in those individuals ascertained through a family member rather than because of neurodevelopmental disorders. To investigate the range of cognitive-behavioral phenotypes associated with 22q11.2 duplication, we studied both probands and their non-proband carrier relatives. Twenty-two individuals with 22q11.2 duplication (10 probands, 12 non-proband carriers) were prospectively assessed with a battery of neuropsychological tests, physical examination, and medical record review. Assessment measures with standardized norms included IQ, academic, adaptive, psychiatric, behavioral, and social functioning. IQ and academic skills were within the average range, with a trend toward lower scores in probands versus non-probands. Adaptive skills were within age expectations. Prevalence of attention deficits (probands only) and anxiety (both groups) was high compared with norms. The prevalence of autism spectrum disorder was relatively low (5% of total sample). Assessment of both probands and non-probands with 22q11.2 duplication suggests that the phenotypic spectrum with respect to neurodevelopment overlaps significantly with the general population. IQ and academic abilities are in the average range for most of the individuals with 22q11.2 duplication in our study, regardless of ascertainment as a proband or non-proband relative. Symptoms of attention deficit and anxiety were identified, which require further study. Results of this study further clarify the phenotype of individuals with 22q11.2 duplication, and provides important information for genetic counseling regarding this recurrent copy number variant.

New Phenotypic Feature in a Patient With a Rare Triplication of the 22q11.2 Region Presenting With Peters Anomaly, Congenital Heart Disease, and Global Developmental Delay: A Case Report and Literature Review

The vulnerability of chromosome 22q11.2 region to rearrangement is due to several low copy repeat (LCR) sequences. These rearrangements are involved in syndromes that share similar phenotypic features. The rearrangements of the 22q11.2 chromosomal region are common, specifically, duplications and deletions associated with congenital anomalies and developmental disabilities disorders. However, the features associated with this chromosomal rearrangement remain largely unknown. We present, to the best of our knowledge, the third patient affected by triplication of the 22q11.2 chromosome region, who presents with Peters anomaly, global developmental delay, patent ductus arteriosus, and subaortic stenosis. This case highlights a new phenotypic feature associated with triplication of this genomic region.