[Genetic diagnosis for a Chinese Han family with primary hypertrophic osteoarthropathy].

OBJECTIVE: To identify the genetic cause for a Chinese Han family affected with primary hypertrophic osteoarthropathy. METHODS: Whole blood and urine samples were collected from a patient and 7 unaffected relatives of the family. The coding sequences and intron/exon boundaries of HPGD and SLCO2A1 genes of the patient were amplified with polymerase chain reaction and sequenced. The genotypes of relatives were subsequently verified. Urinary prostaglandin level was measured with enzyme-linked immunosorbent assay (ELISA). RESULTS: A homozygous 2-bp deletion in HPGD gene (c.310_311delCT, or p.L104AfsX3) was detected in the patient, and 5 heterozygous carriers were identified in the relatives. The urinary prostaglandin E2 (PGE2) level was significantly elevated (P<0.01), while PGE-M was significantly reduced (P<0.01) in the patient. CONCLUSION: Primary hypertrophic osteoarthropathy in this family is caused by a homozygous mutation (c.310_311delCT) in the HPGD gene.

Identification of mutations in the prostaglandin transporter gene SLCO2A1 and its phenotype-genotype correlation in Japanese patients with pachydermoperiostosis.

BACKGROUND: Pachydermoperiostosis (PDP) is a rare genetic disorder characterized by 3 major symptoms: pachydermia including cutis verticis gyrata (CVG), periostosis, and finger clubbing. Recently, a homozygous mutation in the gene HPGD, which encodes 15-hydroxyprostaglandin dehydrogenase (15-PGDH), was found to be associated with PDP. However, mutations in HPGD have not been identified in Japanese PDP patients. OBJECTIVE: We aimed to identify a novel responsible gene for PDP using whole exome sequencing by next-generation DNA sequencer (NGS). METHODS: Five patients, including 2 patient-parent trios were enrolled in this study. Entire coding regions were sequenced by NGS to identify candidate mutations associated with PDP. The candidate mutations were subsequently sequenced using the Sanger method. To determine clinical characteristics, we analyzed histological samples, as well as serum and urinary prostaglandin E2 (PGE2) levels for each of the 5 PDP patients, and 1 additional patient with idiopathic CVG. RESULTS: From initial analyses of whole exome sequencing data, we identified mutations in the solute carrier organic anion transporter family, member 2A1 (SLCO2A1) gene, encoding prostaglandin transporter, in 3 of the PDP patients. Follow-up Sanger sequencing showed 5 different SLCO2A1 mutations (c.940+1G>A, p.E427_P430del, p.G104*, p.T347I, p.Q556H) in 4 unrelated PDP patients. In addition, the splice-site mutation c.940+1G>A identified in 3 of 4 PDP patients was determined to be a founder mutation in the Japanese population. Furthermore, it is likely that the combination of these SLCO2A1 mutations in PDP patients is also associated with disease severity. CONCLUSION: We found that SLCO2A1 is a novel gene responsible for PDP. Although the SLCO2A1 gene is only the second gene discovered to be associated with PDP, it is likely to be a major cause of PDP in the Japanese population.

A case of primary hypertrophic osteoarthropathy without skin involvement (Currarino's disease).

Hypertrophic osteoarthropathy is characterized by digital clubbing, arthropathy and periostosis of long tubular bones. Currarino's disease is an extremely rare variant of primary hypertrophic osteoarthropathy in which there is delayed closure of the fontanelles and an absence of skin involvement. Most reported cases have been in blacks. We report a case in a Caucasian adolescent.