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
