Clinical features and gene mutation analysis of cartilage oligomeric matrix protein in a family with pseudoachondroplasia

Objective To investigate cartilage oligomeric matrix protein(COMP)gene mutation in a three-generation pedigree with two cases of pseudoachondroplasia, and to definitize genotype-phenotype correlation. Methods The clinical data and peripheral blood were collected from the patients with pseudoachondroplasia and their family members. All the 19 exons and their flanking sequences of COMP gene in two patients and three unaffected family numbers and 50 unrelated individuals were analyzed by PCR amplification and direct sequencing. Results The proband, a 6-year-old girl presented with typical clinical features of pseudoachondroplasia, including disproportionate short limb dwarfism, staggering gait, double genu varus deformity, and wider clinical and imaging long bone metaphysis. The 33-year-old father showed a similar manifestation including disproportionate short limb dwarfism and double genu varus deformity, and was performed correcting operation on lower limbs for double genu varus at the age of 10 years. DNA sequencing analysis of the COMP gene revealed a del mutation(c.1417_1419delGAC)in exon 13 in two patients with pseudoachondroplasia, but not in the other unaffected members from the pedrgree and 50 control subjects. Conclusion A del mutation c. 1417_1419delGAC of COMP gene may contribute to the disease in the pedigree. Key words: Pseudoachondroplasia; Cartilage oligomeric matrix protein; Gene mutation