Pachyonychia congenita of the Jadassohn-Lewandowski type

This is a type of pachyonychia congenita (elephant nails from birth). The characteristic features include: {{}}Abnormally thick curved nails (onychogryposis) Thickening of the skin (hyperkeratosis) of the palms, soles, knees and elbows White plaques (leukoplakia) in the mouth Excess sweating (hyperhidrosis) of the hands and feet Teeth are already erupted at birth (natal teeth) Generation after generation in a family may show the syndrome. It is an autosomal dominant trait. The gene responsible for the syndrome is on chromosome 12 (in band 12q13) and a single copy of the gene (named PD1) is capable of causing the disease. The basic abnormality is a mutation (change) in a gene for keratin, a primary constituent of nails, hair, and skin. Alternate names for the syndrome include pachyonychia congenita with natal teeth and type 1 pachyonychia congenita. The syndrome is named for the professor of dermatology at the University of Bern in Switzerland, Josef Jadassohn (1860-1936), and his colleague, Felix Lewandowski (1879-1921), who first described the syndrome in 1906. About their patient, a 15-year-old girl, they wrote: "The nail plates of all the fingers and toes are extremely thickened, and so hard that they cannot be cut with a scissors; the father has to trim them with a hammer and chisel."