Patient reports: Two novel frameshift mutations in the SOX9 gene in two patients with campomelic dysplasia who showed long-term survival.

Campomelic dysplasia (CD) is a rare and usually fatal congenital skeletal disorder with respiratory failure. The SOX9 gene has been cloned as a candidate gene for CD. Here, we report the cases of 2 Japanese patients with CD who have survived for over 5 years. Molecular investigations revealed novel frameshift mutations in SOX9 in these patients; a single G insertion in 1 allele at nucleotide 261 (261-262insG) and a single C insertion in 1 allele at nucleotide 888 (888-889insC). The predicted protein of 261-262insG may lack more than 80% composition of the normal SOX9 protein, including the SRY high mobility group (HMG) domain and the transactivation (TA) domain; the predicted protein of 888-889insC may not contain the normal TA domain. Although it has been reported that most patients with CD die during the neonatal period, our patients have survived for a long time, despite putative severely impaired SOX9 proteins.