Autosomal recessive palmoplantar hyperkeratosis and congenital alopecia (PPK-CA) is a rare genetic skin disorder characterized by congenital alopecia and palmoplantar hyperkeratosis. It is usually associated with cataracts, progressive sclerodactyly and pseudo-ainhum.
To date, autosomal recessive PPK-CA has been reported in two families (seven affected individuals). An additional sporadic patient was likely affected by the same condition.
Similarly to the dominant variant, autosomal recessive PPK-CA usually presents during infancy. Its very early onset is often characterized by fading of facial, scalp and body hair within the first months of life without subsequent re-growth. Body and facial keratosis pilaris are additional features which appear in the following years. Skin thickening of palms and soles develops during infancy and may have an unusual pattern affecting the two sides of fingers and palms, but usually sparing the palmar surfaces. Periungueal involvement is typical and leads to secondary nail dystrophy. Autosomal recessive PPK-CA shows a relatively more severe evolution compared to the dominant variant as many patients develop sclerodactyly, small joint contractures and pseudo-ainhum. The original family also had congenital cataract.
The genetic basis of autosomal recessive PPK-CA is unknown.
Palmoplantar keratoderma and congenital alopecia is also found in ectodermal dysplasias and keratinization disorders, including hidrotic ectodermal dysplasia; hypotrichosis-osteolysis-periodontitis-palmoplantar keratoderma syndrome; KID syndrome; odonto-onycho-dermal dysplasia; Lelis syndrome; mutilating palmoplantar keratoderma with periorificial keratotic plaques; and Schöpf-Schulz-Passarge syndrome (see these terms).
Transmission appears to be autosomal recessive.
Last update: July 2013