Ichthyosis of the swimsuit area (BSI). It is a rare variant of autosomal recessive congenital ichthyosis (ICAR) characterized by the presence of large dark scales in specific areas of the body.
Summary
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- 1 Epidemiology
- 2 Clinical description
- 3 Etiology
- 4 Source
epidemiology
Fewer than 20 patients have been described in the literature.
Clinical description
This particular aspect of the skin appears after the detachment of a collodion membrane present at birth. Unlike other forms of ICAR, the extremities (with the exception of the folds) and the face are not affected by ichthyosis. Scales are present on the hottest areas of the skin, such as the trunk, scalp, and axillary region. In the affected areas, the patient presents large dark scales similar to those observed in lamellar ichthyosis (IL).
Etiology
BSI is caused by specific thermo-sensitive mutations in the TGM1 gene (which encodes transglutaminase 1, which participates in cornification of the stratum corneum). The affected areas of the skin (the areas with the highest temperature) show clearly reduced enzyme activity in contrast to healthy areas of the skin, which show almost normal enzyme activity. Transmission is autosomal recessive.
