Analysis Of 2 Cases Of Vitamin D-dependent Rickets With IA Type

Objective: Analyse the characteristics of vitamin D-dependent rickets ⅠA（VDDR-ⅠA）,compare mutations of 1 α-hydroxylase coding gene（CYP27B1）,and then explore the diagnosis and treatment of VDDR-ⅠA.Methods: two cases of VDDR-ⅠA were analyzed retrospectively by exploring their clinical manifestations,laboratory data（Blood Calcium,Phosphorus,parathyroid hormone and etc.）,imaging data.Meanwhile,the adjacent regions of nine exons and some introns of CYP27B1 gene,which from two patients and their parents were amplified by PCR and sequenced by DNA.Results: The typical clinical manifestations,laboratory findings and imaging findings of rickets were found in both cases.The homozygous mutation of c.1319₁325 dupCCCACCC and single heterozygous mutation of c.1319₁325 dupCCCACCC were detected in exon 8 of CYP27B18 gene in both cases.The two cases were diagnosed as VDDR-I A.All of them were treated with calcitriol and oral calcium.The growth and development were followed up for a long time.Blood calcium,phosphorus,alkaline phosphatase,parathyroid hormone and skeletal photographs were reviewed regularly.The clinical symptoms of rickets were alleviated.The results of follow-up laboratory examination and imaging showed that they were better than those of untreated children.Conclusion: In terms of treatment,there is no uniform standard for VDDR IA at home and abroad.Homozygous mutation of c.1319₁325 dupCCCACCC should be noted in VDDR-IA cases.