A rare variant of autosomal recessive congenital ichthyosis. Less than 20 patients are reported in the literature. Large dark scales are present on warmer skin areas such as the trunk, the scalp, and the axillary region. On affected areas, the scales are similar to those observed in lamellar ichthyosis. Caused by specific thermo-sensitive mutations in the TGM1 gene (encoding transglutaminase 1, involved in the cornification of the stratum corneum). Affected skin areas, show a clearly reduced enzyme activity in contrast to healthy skin areas that demonstrate an almost normal enzyme activity. Transmission is autosomal recessive.