Interstitial microdeletion of the 1p34.3p34.2 region

Background Interstitial microdeletions of chromosome 1p34.3p34.2 are rare, but are continuing to be identified by the use of chromosome microarray. There have been fewer than 10 individuals identified who have deletions of the 1p34.3p34.2 region; all of these previously described individuals have deletions of the AGO 1, AGO 3, GRIK 3, SLC 2A1 , or RIMS 3 genes. Haploinsufficiency of these genes has been associated with neurodevelopmental delays. Methods Chromosome microarray, quantitative PCR , and fluorescence in situ hybridization were performed with DNA extracted from peripheral blood. Results Chromosome microarray identified a 2.3 Mb 1p34.3p34.2 one copy deletion in our patient with global developmental delay, mild intellectual disability, delayed bone age, bilateral vesicoureteral reflux, vocal cord paralysis, right aberrant subclavian artery, kyphoscoliosis, bilateral metatarsus adductus, and valgus knee deformity. This deletion was confirmed by quantitative PCR and does not include the AGO 1, AGO 3, GRIK 3, SLC 2A1 , or RIMS 3 genes. Subsequent FISH testing of the parents was negative. Conclusion Haploinsufficiency of the 1p34.3p34.2 region, including the SNIP 1 gene and excluding the five genes listed above, is responsible for the neurocognitive delays and other symptoms as identified in our patient.