Rickets - Genes & Biomarkers Summary Biomarker / Gene Bad Score Free Actions Non-free Actions GENES PHEX Pathogenic variant Family cascade screening Burosumab (Crysvita) FGF23 Gain-of-function mut. Dietary advice Phosphate + calcitriol CYP27B1 Biallelic mutation Vit D-rich diet, sun Calcitriol / alfacalcidol VDR Biallelic mutation High-calcium diet High-dose calcitriol BIOMARKERS Phosphate (Pi) <1.0 mmol/L High-P diet, limit losses Oral phosphate supplements ALP >400 U/L Weight-bearing activity Treat underlying rickets 25-OH Vitamin D <30 nmol/L Sun exposure, fatty fish Vit D3 supplements PTH >65 pg/mL Calcium-rich foods Cinacalcet / surgery