Biochemical investigations showed vitamin D < 14 nmol/L (NR > 50), alkaline phosphatase 665 U/L (NR 30–130), parathyroid hormone 52.8 pmol/L (NR 1.6–7.5), calcium 2.43 mmol/L (NR 2.2–2.6) and phosphate 1.07 mmol/L (NR 0.8–1.5), in keeping with hyperparathyroidism secondary to vitamin D deficiency and chronic kidney disease (creatinine 169 μmol/L and estimated glomerular filtration rate 34 mL/min). Here, PTH is linked to vitamin D deficiency.