Background: Biallelic pathogenic variants in CYP24A1 can cause idiopathic infantile hypercalcemia (HCINF).
Methods: We report 2 additional molecular abnormalities in 2 Chinese children with CHINF1.
Results: 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.
Conclusion: Genetic tests are helpful in order to counsel the susceptible individuals to avoid vitamin D and take preventive measures in order to avoid complications.
Keywords: CYP24A1; Chinese; idiopathic infantile hypercalcemia.