Syndromic craniosynostosis due to complex chromosome 5 rearrangement and MSX2 gene triplication.

Craniosynostosis is a common birth defect ( approximately 1/3,000 births) resulting from chromosome imbalances, gene mutations or unknown causes. We report a 6-month-old female with multiple sutural synostosis and prenatal onset growth deficiency, developmental delay, facial dysmorphism, congenital heart defect, and inguinal hernia. An integrated approach of standard cytogenetics, mBAND, locus-specific FISH, and 75 kb resolution array-CGH disclosed a complex chromosome 5 rearrangement, resulting in 3 paracentric inversions, 2 between-arm insertions, and partial duplication of 5q35. An extra copy of the MSX2 gene, which maps within the duplicated segment and is mutated in Boston-type craniosynostosis, was confirmed by molecular cytogenetic studies. Our study confirms that early fusion of cranial sutures commonly observed in the dup(5q) syndrome is caused by triplication of the MSX2 gene and strongly supports the crucial role of this gene in the development of craniofacial structures.