Figure 2.

Clinical approach to investigation of causes of hypercalcemia in a child. ^aConfirm hypercalcemia, defined as plasma (or serum) adjusted calcium > 10.5  mg/dL (2.60 mmol/L) or ionized calcium > 5.25 mg/dL (1.32 mmol/L) (see Table 2). ^bPTH–parathyroid hormone. ^c25(OH)D–25‐hydroxyvitamin D. ^dFHH1‐3– Familial Hypocalciuric Hypercalcemia types 1‐3; MEN1–Multiple Endocrine Neoplasia type 1; MEN2–Multiple Endocrine Neoplasia type 2; MEN3–Multiple Endocrine Neoplasia type 3; MEN4–Multiple Endocrine Neoplasia type 4; NSHPT–Neonatal Severe Primary Hyperparathyroidism; HPT‐JT–Hyperparathyroid‐Jaw Tumour syndrome. ^eFamilial Isolated Hyperparathyroidism. ^fConditions affecting neonates (shown in italics). ^g1,25(OH)₂D–1,25‐dihydroxyvitamin D. ^hInborn errors of metabolism, e.g. Hypophosphatasia, Congenital Lactase Deficiency (CLD) and blue diaper syndrome. ⁱThese syndromes may be associated with dysmorphic features, e.g. Williams syndrome, Jansen's metaphyseal chondrodysplasia, Hypophosphatasia.