25-hydroxyvitamin-d-2 and Xeroderma-Pigmentosum

Xeroderma pigmentosum (XP) is a rare autosomal recessive disease characterized by defective repair of ultraviolet (UV) irradiation-induced DNA damage and high risk of skin cancer. Thus, these patients require strict photoprotection. Considering the importance of UV-mediated cutaneous vitamin D production, such rigorous photoprotection would cause vitamin D deficiency. Then, we have studied the vitamin D status in patients with XP-A, a group requiring the most strict photoprotection.. Twenty-one patients with XP-A (aged 6-25) were evaluated for their vitamin D intake, serum levels of 25-hydroxy-vitamin D (25OHD) and parathyroid hormone (PTH). Vitamin D intake was assessed by a 2-day food weighing method.. Median dietary intake of vitamin D was 4.1 μg/day, and the median concentrations of serum 25OHD and PTH were 7.7 and 49.9 pg/ml, respectively. In 76% of the patients, serum 25OHD level was lower than 10 ng/ml, indicating vitamin D deficiency. Vitamin D intake and serum 25OHD level were significantly lower in patients under enteral nutrition (EN) than those with oral intake (OI). Multivariate analyses revealed that EN was a significant predictor of decreased serum 25OHD level (β coefficient=-0.59, P=0.03).. Vitamin D deficiency is highly prevalent in XP-A patients, and supplementation should be considered to avoid unfavorable skeletal consequences in these patients. In addition, determination of dietary vitamin D requirement has been a difficult work issue in the decision of dietary reference intakes (DRIs) because of its cutaneous production. Data from XP patients would yield useful information for the determination of DRIs for vitamin D.

Topics: 25-Hydroxyvitamin D 2; Adolescent; Adult; Calcifediol; Child; Combined Modality Therapy; Cross-Sectional Studies; Female; Hospitals, University; Humans; Japan; Life Style; Male; Nutritional Status; Outpatient Clinics, Hospital; Parathyroid Hormone; Patient Compliance; Prevalence; Risk; Skin Neoplasms; Sunscreening Agents; Vitamin D Deficiency; Xeroderma Pigmentosum; Young Adult

A simplified method for the determination of 25-hydroxy and 1alpha,25-dihydroxy metabolites of vitamins D2 and D3 in human plasma was developed. Plasma samples were deproteinizated and applied to a Bond Elut C18OH cartridge to separate 25-hydroxyvitamin D (25-OH-D) and 1alpha,25-dihydroxyvitamin D [1,25(OH)2D] fractions. The 25-OH-D fraction was purified by a Bond Elut C18 cartridge and 25-OH-D2 and 25-OH-D3 were assayed by HPLC using a Zorbax SIL column. The 1,25(OH)2D fraction obtained above was subsequently applied to HPLC using a Zorbax SIL column to separate 1,25(OH)2D2 and 1,25(OH)2D3 fractions which were determined by a radioreceptor assay (RRA) using calf thymus receptor. The method was applied to nutritional studies.

Topics: 25-Hydroxyvitamin D 2; Adult; Aged; Calcifediol; Calcitriol; Chromatography, High Pressure Liquid; Ergocalciferols; Food, Fortified; Humans; Hydroxycholecalciferols; Infant; Middle Aged; Xeroderma Pigmentosum