Prenatal Diagnosis and Elucidation of a Novel Molecular Mechanism in Carpenter Syndrome

Abstract

Carpenter syndrome is a rare autosomal recessive disorder characterized by craniosynostosis, polydactyly and syndactyly. The gene Rab23 was identified in 2007, following which there have been only four reports describing different types of mutations. The authors describe herein a case that was diagnosed solely on the basis of history, antenatal ultrasound findings and fetal photographs taken by a cellular phone. Subsequent molecular studies revealed a novel homozygous mutation in the Rab23 gene. This mutation which converted the stop codon into a coding one, results in the formation of a lengthened 307 amino acids protein in contrast to the wild type protein containing 237 amino acids. The secondary structure prediction by PSIpred revealed that the C-terminal region of the longer mutated Rab23 protein contains several helices/strands resulting in the loss of structural flexibility and consequently, prenylation. This made it possible to offer prenatal testing to this family in its next conception where the fetus was unaffected. This case reports a novel molecular mechanism and the utility of integrating the cellular phone into clinical practice.

Keywords

Craniosynostosis - Lengthened protein - Stop codon mutation - Carpenter syndrome - Prenatal diagnosis

Publication History

Received: 09 September 2014

Accepted: 27 September 2014

Article published online:
08 May 2023