1. Biallelic mutations in CYP24A1 or SLC34A1 as a cause of infantile idiopathic hypercalcemia (IIH) with vitamin D hypersensitivity: molecular study of 11 historical IIH cases
- Author
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Rowińska E, Agnieszka Jacoszek, Janusz Książyk, Aldona Wierzbicka, Ewa Pronicka, Karl P. Schlingmann, Dariusz Rokicki, Paweł Płudowski, Mieczysław Litwin, Paulina Halat, Marek Wójcik, Ewa Wojciechowska, Agnieszka Janiec, Martin Konrad, and Elżbieta Ciara
- Subjects
Adult ,Male ,0301 basic medicine ,Heterozygote ,medicine.medical_specialty ,DNA Mutational Analysis ,Idiopathic infantile hypercalcemia ,030209 endocrinology & metabolism ,Rickets ,Biology ,Sodium-Phosphate Cotransporter Proteins, Type IIa ,Compound heterozygosity ,Gastroenterology ,Human Genetics • Short Communication ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Gene Frequency ,CYP24A1 ,Internal medicine ,Genetics ,medicine ,Vitamin D and neurology ,Adults ,Humans ,Hypercalciuria ,Vitamin D ,Vitamin D3 24-Hydroxylase ,Vitamin D hypersensitivity ,Incidence (epidemiology) ,Homozygote ,General Medicine ,Biallelic mutations ,medicine.disease ,Nephrocalcinosis ,030104 developmental biology ,Endocrinology ,Mutation ,Failure to thrive ,Hypercalcemia ,Female ,Poland ,medicine.symptom ,SLC34A1 - Abstract
Idiopathic infantile hypercalcemia (IIH) is a mineral metabolism disorder characterized by severe hypercalcemia, failure to thrive, vomiting, dehydration, and nephrocalcinosis. The periodical increase in incidence of IIH, which occurred in the twentieth century in the United Kingdom, Poland, and West Germany, turned out to be a side effect of rickets over-prophylaxis. It was recently discovered that the condition is linked to two genes, CYP24A1 and SLC34A1. The aim of the study was to search for pathogenic variants of the genes in adult persons who were shortlisted in infancy as IIH caused by “hypersensitivity to vit. D”. All persons were found to carry mutations in CYP24A1 or SLC34A1, nine and two persons respectively. The changes were biallelic, with one exception. Incidence of IIH in Polish population estimated on the basis of allele frequency of recurrent p.R396W CYP24A1 variant, is 1:32,465 births. It indicates that at least a thousand homozygotes and compound heterozygotes with risk of IIH live in the country. Differences in mechanism of developing hypercalcemia indicate that its prevention may vary in both IIH defects. Theoretically, vit. D restriction is a first indication for CYP24A1 defect (which disturbs 1,25(OH)2D degradation) and phosphate supplementation for SLC34A1 defect (which impairs renal phosphate transport). In conclusion, we suggest that molecular testing for CYP24A1 and SLC34A1 mutations should be performed in each case of idiopathic hypercalcemia/hypercalciuria, both in children and adults, to determine the proper way for acute treatment and complications prevention.
- Published
- 2017
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