Autosomal recessive congenital ichthyosis in Sweden and Estonia: clinical, genetic and ultrastructural findings in eighty-three patients.

Congenital (non-bullous) ichthyosis is a rare group of keratinizing disorders which can be tentatively subclassified based on clinical criteria, analysis of transglutaminase 1 gene mutations and electron microscopy of epidermis. We studied 83 patients who were all on topical therapy and in 16 cases also on oral retinoids. Three main groups of patients were distinguished: (A) those with transglutaminase 1 gene mutations (n=44), (B) those without transglutaminase 1 gene mutations showing a coarse, generalized scaling (n=19), and (C) those without transglutaminase 1 gene mutations showing only fine or focal scaling (n=20). On clinical scoring, patients in group A were more hyperkeratotic and less erythematous than those in group B (p < 0.05). Anhidrosis was recorded in nearly all patients (> or = 80%), but ectropion and a collodion phenotype at birth were more common in group A versus other groups. Ultrastructurally, a high frequency of type I (Anton-Lamprecht's classification) was found in all three groups (37-63%), 20 cases of type II in group A and a few cases of types III and IV in groups B and C, respectively. In conclusion, transglutaminase 1 gene mutation is a major cause of congenital ichthyosis in Sweden and Estonia, and is often associated with severe scaling and ultrastructural type II in corneocytes. The transglutaminase-unrelated cases are more heterogeneous, probably reflecting a more varied aetiology.

Harlequin ichthyosis in two greater kudu (Tragelaphus strepsiceros).

Two greater kudu calves (Tragelaphus strepsiceros) born 7 years apart were found with fissures and thickened, scaly, cutaneous plates covering over 80% of their bodies. One was dead at presentation, and the other was euthanized shortly after birth. Both animals shared a common sire. On necropsy, chemosis, ectropion, eclabium, and bilateral valgus deformities of the tarsal joints were observed in one calf, presumed to be secondary to the plates restricting normal fetal development. The principal microscopic lesion was severe lamellar orthokeratosis, with focal mild parakeratosis. Ultrastructural epidermal lesions included the absence of normal lamellar granules, large dilated endoplasmic reticulum, and abnormal retention of organelles and vesicles. Gross, histopathologic, and electron microscopic findings in both kudu calves were consistent with those of harlequin ichthyosis, a rare dermatosis of humans believed to have an autosomal recessive inheritance pattern. The underlying genetic and molecular abnormality and heritability of this condition in this greater kudu herd were not determined.