[Clinical and genetic analysis of a boy with 9q34.3 microdeletion syndrome].

OBJECTIVE: To determine the origin of chromosomal aberration in a boy with mental retardation and multiple congenital malformations.

METHODS: The karotypes of the proband and his parents were analyzed with conventional G-banding. Their genomic DNA was analyzed with array comparative genomic hybridization (aCGH).

RESULTS: No karyotypic abnormality was detected in the proband and his parents. aCGH has identified a de novo 405 kb deletion at 9q34.3 in the proband, which encompassed the EHMT1 gene and part of CACNA1B gene.

CONCLUSION: The de novo 9q34.3 deletion probably underlies the mental retardation and development delay in the boy. EHMT1 may be one of the key genes responsible for 9q34.3 microdeletion syndrome.