Seborrhea-Like Dermatitis With Psoriasiform Elements

A number sign (#) is used with this entry because of evidence that the disorder is caused by mutation in the ZNF750 gene (610226).

Clinical Features

Birnbaum et al. (2006) described an Israeli Jewish Moroccan family presenting with autosomal dominant seborrhea-like dermatitis with psoriasiform elements, including enhanced keratinocyte proliferation, parakeratosis, follicular plugging, Pityrosporum ovale overgrowth, and dermal CD4 lymphocyte infiltration. The disorder had occurred in 44 individuals in 5 generations. All affected family members presented by 10 years of age with a similar phenotype: a chronic fine diffuse scaly erythematous rash on the face, particularly on the chin, nasolabial folds and eyebrows, around earlobes and over the scalp. The rash was exacerbated in winter, as well as with emotional stress and after strenuous physical activity. Hyperkeratosis of skin over the elbows, knees, palms, soles, and metacarpophalangeal joints was evident. There was no arthralgia, arthritis, or neurologic disorder. Skin biopsies demonstrated mild psoriasiform thickening (acanthosis) of the epidermis, hyperkeratosis, focal and shouldering parakeratosis, scale crusts, follicular hyperkeratotic plugs, and overgrowth of Pityrosporum ovale. There was no significant spongiosis typical of seborrheic dermatitis, and no evidence of clusters of neutrophils in parakeratotic layers as seen in psoriasis.

Mapping

By genomewide linkage analysis of 18 family members, Birnbaum et al. (2006) mapped the disorder to the telomeric end of chromosome 7q25 with a maximum multipoint lod score of 8.79. This region overlaps the locus for psoriasis susceptibility-2 (PSORS2; 602723).

Molecular Genetics

In all affected members of the family with seborrhea-like dermatitis with psoriasiform elements studied by them, Birnbaum et al. (2006) identified heterozygosity for a frameshift mutation in the ZNF750 gene (610226.0001), which encodes a putative C2H2 zinc finger protein. ZNF750 is normally expressed in keratinocytes but not in fibroblasts and is barely detectable in CD4 lymphocytes.