CYP24A1 Variants in Two Chinese Patients with Idiopathic Infantile Hypercalcemia

Biallelic pathogenic variants in CYP24A1 can cause idiopathic infantile hypercalcemia (HCINF).

We report 2 additional molecular abnormalities in 2 Chinese children with CHINF1.

Biallelic variants in CYP24A1 were found in two patients. Patient One was compound heterozygous for c.449 + 1G > T and c.1426_1427delCT. Patient Two was compound heterozygous for c.1310C > A and c.1426_1427delCT. The c.1310C > A and c.449 + 1G > T were two different novel CYP24A1 variants. Multiple computational tools predicted that both impact protein function. A total of 36 variants have been previously reported in patients with HCINF1, of which 27 were classified as pathogenic or likely pathogenic and nine as uncertain clinical significance.

Genetic tests are helpful in order to counsel the susceptible individuals to avoid vitamin D and take preventive measures in order to avoid complications.