Rickets

Definition:
Rickets is a childhood disorder caused by defective mineralization of growing bones due to Vitamin D deficiency.

Biochemical Basis / Cause:

• ↓ Vitamin D → ↓ calcium & phosphate absorption from intestine → hypocalcemia → defective bone matrix mineralization.

Types (with cause):

• Nutritional rickets – diet low in Vitamin D, less sunlight.

• Renal rickets – chronic kidney disease (↓ 1,25-(OH)₂D₃ formation).

• Vitamin D–dependent rickets – genetic defect in vitamin D metabolism.

Real Data / Key Points:

• Serum calcium: ↓ or normal

• Serum phosphate: ↓

• Alkaline phosphatase: ↑ (marker of increased osteoblastic activity)

Classical Signs:

• Bowed legs (genu varum), rachitic rosary (costochondral swelling), delayed dentition.