Ca | Phos | Alk phos | iPTH | 25-(OH)D | 1,25-(OH)2D | Urine Ca/Cr | TRP | |
---|---|---|---|---|---|---|---|---|
Nutritional/insufficient sunlight | N or ↓ | ↓ | ↑ | ↑ | ↓ | ↑ | ↓ | ↑ |
Malabsorption | N or ↓ | ↓ | ↑ | ↑ | ↓ | ↑ | ↓ | ↑ |
Renal tubular defects | N or ↓ | ↓ | ↑ | ↑ | N | ↑ | ↑ | N or ↓ |
Altered vitamin D metabolism | N or ↓ | ↓ | ↑ | ↑ | ↓ | ↑ | ↓ | ↑ |
Genetic forms of rickets | ||||||||
X-linked, AD, and AR hypophosphatemic rickets | N | ↓ | ↑ | N or ↑ | N | N or ↑ | N or ↓ | ↓ |
1a-hydroxylase deficiency | ↓ | ↓ | ↑ | ↑ | N | ↓ | ↓ | ↑ |
Vitamin D receptor mutations (vitamin D resistance) | ↓ | ↓ | ↑ | ↑ | N | ↑ | ↓ | ↑ |
Hereditary hypophosphatemic rickets with hypercalciuria | N or ↓ | ↓ | ↑ | ↑ | N | ↑ | ↑ | ↓ |
Hypophosphatasia | N or ↑ | N or ↑ | ↓ | N or ↓ | N | N or ↓ | N or ↑ | N |
Ca, calcium; phos, phosphorus; alk phos, alkaline phosphatase; iPTH, intact parathyroid hormone; 25-(OH)-D, 25-hydroxy vitamin D; 1,25-(OH)2-D, 1,25-dihydroxy vitamin D; Ca/Cr, calcium/creatinine ratio; TRP, tubular reabsorption of phosphorus ([1 − (U phos × P Cr/U Cr × S Phos)] × 100, normal 85–95%); AD, autosomal dominant; AR, autosomal recessive; N, normal.
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