Vitamin D-dependent rickets type 1B (VDDR1B) is an autosomal semidominant genetic disorder caused by a deficiency in CYP2R1, which encodes vitamin D 25-hydroxylase, an enzyme that plays a crucial role in the conversion of vitamin D to 25-dihydroxyvitamin D3. VDDR1B is a severe form of rickets that occurs during infancy and which is responsive to 25-OH vitamin D supplementation. We studied three adult patients from a multi-consanguineous family with VDDR1B. They have been diagnosed with pseudo-nutritional rickets and treated during their adolescence with 25-OH vitamin D. These patients stopped their treatments at the end of adolescence and were contacted 14 to 17 years later when VDDR1B diagnosis was carried out in their niece and nephews. These three patients had undetectable 25-OH vitamin D, but normal levels of plasma 1-25(OH)2 vitamin D. All patients had a hip bone mineral density and a normal vertebral despite osteoarthritis degenerative lesions which may impact BMD evaluation. These findings show that vitamin D supplementation has a questionable effect, if any, for osteoporosis prevention in adulthood in contrast to its crucial importance during infancy and adolescence.

中文翻译：

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维生素D 25-羟化酶缺乏症（CYP2R1）成年患者长期25-OH维生素D缺乏症不会损害骨矿物质密度。

维生素D依赖型病1B型（VDDR1B）是由CYP2R1缺乏引起的常染色体半显性遗传疾病，它编码维生素D 25-羟化酶，该酶在维生素D转化为25-二羟基维生素D3中起着至关重要的作用。VDDR1B是a病的一种严重形式，发生于婴儿期，对补充25-OH维生素D有反应。我们研究了来自多血缘家庭VDDR1B的三名成年患者。他们被诊断出患有假营养性病，并在青春期期间接受25-OH维生素D的治疗。这些患者在青春期结束时停止治疗，并在14至17年后在侄女和侄儿进行VDDR1B诊断时与他们联系。 。这三名患者均检测不到25-OH维生素D，但血浆中1-25（OH）2维生素D的水平正常。尽管有可能影响BMD评估的骨关节炎退化性病变，所有患者的髋骨矿物质密度和椎骨均正常。这些发现表明，维生素D补充剂对预防成年期骨质疏松症具有可疑的作用，而在婴儿期和青春期则至关重要。