Oral 13, An unexplained disorder of keratinization

A 6‐year‐old boy initially presented at the age of 1 week with perineal and perianal rash. The rash was persistent and at the age of 8 months he developed gastroenteritis. He was found to have borderline zinc deficiency. However, there was no improvement with zinc supplementation and the rash progressed to well‐demarcated psoriasiform plaques involving the perianal area, penis, scrotum, upper thighs, face, axillae, right elbow and neck. He also developed palmoplantar keratoderma. Initially the hair was sparse and brittle. He developed recurrent chest and skin infections. There was a family history of malignant hyperpyrexia and mitochondrial myopathy. Skin biopsy was nonspecific, showing chronic superficial dermatitis. Analysis of skin and blood for recognized keratin and connexin disorders did not show any abnormalities. Gastroenterology investigations revealed oesophagitis, gastritis and patchy pancolitis. Routine blood tests were normal. Lactate levels, acylcarnitine profile, organic acids, tubulopathy screen, glycosaminoglycans, biotinidase, betamethylcarboxyl CoA carboxylase, holocarboxylase synthetase, prolidase and tyrosine aminotransferase levels were normal. Autoimmune screen and immunological investigations were normal. Blood tests for coeliac disease were negative. Electromyography and DNA analysis for mitochondrial myopathy were normal. Sweat studies and cystic fibrosis gene analysis were normal. DNA analysis for malignant hyperpyrexia was negative. His skin condition gradually improved on treatment with acitretin 10 mg three times a week and topical emollients. He is still troubled by recurrent infections. His gastroenteritis is well controlled by an oligoantigenic diet. We are grateful to Professor John Harper and Professor David Kelsall for their help in managing this child.