Department of Pediatrics, Sestre milosrdnice University Hospital Center, Zagreb, Croatia.
Acta Clin Croat. 2022 Feb;60(3):544-547. doi: 10.20471/acc.2021.60.03.27.
CYP24A1 is an enzyme that inactivates vitamin D and encodes vitamin D 24-hydroxylase. Mutations in this enzyme have been linked with idiopathic infantile hypercalcemia, nephrolithiasis, and nephrocalcinosis. Genetic testing for this mutation should be considered in the presence of calciuria, elevated serum calcium, elevated 1,25- dihydroxyvitamin D, and suppressed parathyroid hormone. We present a previously healthy eight-month-old male infant with macrohematuria, hypercalciuria (6 mg/kg/24 h), albuminuria (54 mg/24 h) and left-sided nephrolithiasis found on urinary tract ultrasound. The values of alpha 1 microglobulin, parathyroid hormone, vitamin D, serum electrolytes, amino acids, glycols, oxalates and citrates in urine, as well as coagulation tests were normal. Genetic testing excluded suspected Dent's disease but confirmed heterozygous missense variant CYP24A1 c.469C>T, p.(Arg157Trp) classified as polymorphism. He was treated with hydrochlorothiazide and potassium citrate. Children presenting with hypercalcemia, hypercalciuria and nephrolithiasis should be tested because of the importance of recognition, genetic diagnosis and proper treatment of CYP24A1 mutations that can present with a wide range of phenotypic presentations, from asymptomatic to chronic renal disease.
CYP24A1 是一种使维生素 D 失活并编码维生素 D24-羟化酶的酶。该酶的突变与特发性婴儿高钙血症、肾结石和肾钙质沉着症有关。在存在钙尿症、血清钙升高、1,25-二羟维生素 D 升高和甲状旁腺激素抑制的情况下，应考虑对此突变进行基因检测。我们介绍了一名之前健康的 8 个月大男婴，他出现了肉眼血尿、高钙尿症（6mg/kg/24h）、蛋白尿（54mg/24h）和左侧肾结石，在尿路超声检查中发现。尿中α1微球蛋白、甲状旁腺激素、维生素 D、血清电解质、氨基酸、糖、草酸盐和柠檬酸盐以及凝血试验值均正常。基因检测排除了疑似 Dent 病，但证实杂合错义变体 CYP24A1 c.469C>T，p.(Arg157Trp)为多态性。他接受了氢氯噻嗪和柠檬酸钾治疗。由于认识、遗传诊断和适当治疗 CYP24A1 突变的重要性，应检测出现高钙血症、高钙尿症和肾结石的儿童，这些突变可表现出广泛的表型表现，从无症状到慢性肾病。
