Moreover, we confirmed the initial clinical diagnosis of neonatal hyperparathyroidism in one patient (index case CA0110 had a homozygous pathogenic variant in the CASR gene) and infantile hypercalcemia in another patient (index case CA0139 had two pathogenic variants in compound heterozygous state in the CYP24A1 gene). This evidence concerns the gene CASR and neonatal severe primary hyperparathyroidism.