At the same time, cases with normal skin or xerosis are suggestive of X-linked ichthyosis, ichthyosis vulgaris
, erythrokeratodermas, and Sjogren-Larsson syndrome.
3321delA mutation was associated with various AD-associated phenotypes, most of which are related to dry skin phenotypes, including xerosis, ichthyosis vulgaris
(IV), and palmar hyperlinearity.
About a decade ago, loss-of-function mutations in the filaggrin molecule were first implicated in the pathogenesis of ichthyosis vulgaris
and, subsequently, of atopic dermatitis and other atopic diseases.
A study of 100 ama X-hosa children in South Africa with severe AD and ichthyosis vulgaris
symptoms revealed no FLG mutations.
It was only relatively recently, however, that genetic techniques had developed to the point at which it could be demonstrated that loss-of-function mutations in the filaggrin gene cause ichthyosis vulgaris
1 The severity of symptoms can vary enormously, from the mildest types such as ichthyosis vulgaris
which may be mistaken for normal dry skin up to life-threatening conditions such as harlequin ichthyosis.
Filaggrin genotype in ichthyosis vulgaris
predicts abnormalities in epidermal structure and function.
3 It occurs with various skin diseases, such as atopic dermatitis, Wiskott- Aldrich syndrome, pemphigus foliaceus, ichthyosis vulgaris
, bullous pemphigoid, seborrheic dermatitis, psoriasis, irritant contact dermatitis and Darier's disease.