Prenatal diagnosis and genetic analysis of a fetus with 6q27 microdeletion

Objective To determine the origin and pathogenicity of a chromosomal aberration for a fetus and analyze the possible mechanism. Methods The karotypes of the fetus and its parents were analyzed with routine G-banding. Their genomic DNA was also analyzed with array comparative genomic hybridization (aCGH). Results No karyotypic abnormality was detected at cytogenetic level for the fetus and its parents. aCGH has identified a de novo 2.04 Mb deletion at 6q27 in the fetus. The region involves candidate genes responsible for structural brain abnormalities. The area flanking the chromosomal breakpoint contains a 2410 bp sequence rich in palindromes which can form stable secondary structures. Conclusion The de novo 6q27 deletion is pathogenic. The 6q27 deletion may be responsible for the structural brain abnormalities in the fetus. The palindrome sequence flanking the chromosomal breakpoint may be involved the formation of the 6q27 deletion. Key words: 6q27 microdeletion; Prenatal diagnosis; Array comparative genomic hybridization