Pachydermoperiostosis describes a form of primary hypertrophic osteoarthropathy and is characterized by pachydermia, drumstick fingers, and subperiosteal new bone formation.
There are three manifestations of the disease: the complete form with pachydermia and periostitis; the incomplete form indicates evidence of bone abnormalities, but it does precipitate pachydermia; the form of fruste is characterized by minimal or absent skeletal abnormalities with significant pachydermia.
The disease is predominantly found in the male sex (m:f ratio 7: 1). The disease is more severe in male patients than in female patients.
Normally, the disease begins in childhood or adolescence, advances 5-20 years and then becomes stationary, or the progress stagnates. The dermatological symptoms are pachydermia, cutis verticis gyrata, seborrhea, thickened and furrowed facial structures, demous and hyperhidrosis. As rheumatological symptoms, joint effusion, acroosteolysis, subperiosteal ossification and arthritis have been described. In the course of the disease, severe kyphosis may develop with limited mobility and with neurological symptoms. Also congenital heart defects, e.g. Ductus arteriosus is one of the typical complications.
Inheritance of the disease is autosomal recessive, but heterozygous individuals may show mild clinical abnormalities. The cause was found to be mutations in the HPGD gene at the 4q33-q34 locus which encodes the 15-hydroxy-prostaglandin dehydrogenase. The 15-PGDH is a key enzyme in prostaglandin degradation.