What is pachyonychia congenita? Pachyonychia congenita is a
rare, inherited disorder of keratinisation. This is the process
by which keratin is formed and deposited in the outer most layer
of the skin. It occurs due to mutation in the genes encoding
keratin 6a, 6b, 14, 16 or 17. How is it inherited? Pachyonychia
congenita is most often autosomal dominantly inherited. That
means the defective gene comes from one parent. An affected
person has a 50% chance of passing on the disease to his or her
offspring at each pregnancy. A few cases of autosomal recessive
pachyonychia congenita have also been reported, in which a
family history may not be known as the abnormal gene is
inherited from both parents. In this case, on average, one in
every four of the offspring are affected. Sporadic cases may
also arise, due to mutations during conception. What are the
features of pachyonychia congenita? Pachyonychia congenita
affects the skin (especially palms and soles), nails, hair and
mucous membranes. Specific features depe