Abstract
We describe a 15-month-old boy referred to the hospital because of delayed development of motor skills and growth retardation. Blood samples and X-rays of the wrists and knees revealed rickets. He was treated with oral calcium and vitamin D with modest clinical and biochemical effect. 1,25-dihydroxyvitamin D was undetectable in laboratory tests. Vitamin D1alpha-hydroxylase deficiency was suspected and confirmed by DNA analysis, which revealed a 7 bp duplication in exon 8 of the CYP27B1 gene. The treatment was changed to an activated formula of vitamin D, alphacalcidol, whereupon the clinical and biochemical symptoms rapidly improved.
MeSH terms
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25-Hydroxyvitamin D3 1-alpha-Hydroxylase / deficiency*
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25-Hydroxyvitamin D3 1-alpha-Hydroxylase / genetics
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Calcium / administration & dosage
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Growth Disorders / diagnostic imaging
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Growth Disorders / drug therapy
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Growth Disorders / enzymology
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Growth Disorders / etiology
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Hand / diagnostic imaging
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Humans
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Hydroxycholecalciferols / administration & dosage
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Infant
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Male
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Motor Skills
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Radiography
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Rickets / diagnostic imaging
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Rickets / drug therapy
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Rickets / enzymology*
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Rickets / etiology
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Steroid Hydroxylases / deficiency*
Substances
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Hydroxycholecalciferols
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Steroid Hydroxylases
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vitamin D 1-alpha hydroxylase
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25-Hydroxyvitamin D3 1-alpha-Hydroxylase
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Calcium
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alfacalcidol