Vitamin D Status in Distinct Types of Ichthyosis: Importance of Genetic Type and Severity of Scaling.

Abstract

Data on vitamin D status of patients with inherited ichthyosis in Europe is scarce and unspecific concerning the genetic subtype. This study determined serum levels of 25-hydroxyvitamin D3 (25(OH)D3) in 87 patients with ichthyosis; 69 patients were additionally analysed for parathyroid hormone. Vitamin D deficiency was pronounced in keratinopathic ichthyosis (n\u2009=\u200917; median 25(OH)D3: 10.5 ng/ml), harlequin ichthyosis (n\u2009=\u20092;7.0 ng/ml) and rare syndromic subtypes (n\u2009=\u20093; 7.0 ng/ml). Vitamin D levels were reduced in TG1-proficient lamellar ichthyosis (n\u2009=\u200915; 11.9 ng/ml), TG1-deficient lamellar ichthyosis (n\u2009=\u200912; 11.7 ng/ml), congenital ichthyosiform erythroderma (n\u2009=\u200913; 12.4 ng/ml), Netherton syndrome (n\u2009=\u20097; 10.7 ng/ml) and X-linked ichthyosis (n\u2009=\u20098; 13.9 ng/ml). In ichthyosis vulgaris 25(OH)D3 levels were higher (n\u2009=\u200910; 19.7 ng/ml). Parathyroid hormone was elevated in 12 patients. Low 25(OH)D3 levels were associated with high severity of scaling (p\u2009=\u20090.03) implicating scaling as a risk factor for vitamin D deficiency. Thus, this study supports our recent guidelines for ichthyoses, which recommend screening and substituting for vitamin D deficiency.