20 KERATOSIS FOLLICULAR SPINULOSA DECALVANS AND X-LINKED HYPER IGM SYNDROME
Hortala M, Dangoisse Ch, Sznajer Y, Bruderer P, Sass U, Wastelin M, Fester A, Stene JJ
Department of Dermatology, University Hospital, HUDERF, St Pierre, Brugman, University of Brussels, Belgium. Clinical genetics, HUDERF, University of Brussels, Belgium

Keratosis follicular spinulosa decalvans (KFSD) is a rare X-linked disorder, of unknown aetiology, first described by Siemens in 1926. We report a case of a 6 year-old boy, with X-linked hyper IgM syndrome, who developed a progressive non-scarring alopecia, associated with keratosis follicular of the cheeks, the forehead, the upper trunk and the abdomen. The eruption had begun with erythematous follicular papules and plugs on the upper trunk and the abdomen, which transformed into pitlike depression. The eruption extended to the cheeks, the forehead and the eyebrows, in association with a gradual loss of the eyebrows and the hair. Scalp examination revealed a diffuse non-scarring alopecia with a squamous aspect of the skin. A biopsy from the scalp showed fibrosis of collagen fibers with atrophy of the follicle and sebaceous gland. Direct immunofluorescence was negative. Polarized light microscopy of the hair was normal. On the basis of these clinical findings the diagnosis of KFSD was made. KFSD is an uncommon X-linked disorder which has been mapped to Xp21.13-p22-2. It belongs to a group of disorders characterized by follicular hyperkeratosis with different degrees of inflammation, atrophy and distribution of lesions. To the best of our knowledge, this is the first report of KFSD in association with X-linked hyper IgM syndrome. The candidate region for KFSD located on Xp21 chromosome is of 1 Mb size. This region contains gene implicated in KFSD, retinoschisis and spermidine/spermine N acetyltransferase. A contiguous gene syndrome might be responsible for the clinical presentation of the case reported here. Molecular investigation will be performed in order to analyse and precise mechanism that could underline this phenotype.