Type	Causes	Inheritance pattern	Clinical features	Treatment*
Nutritional rickets or vitamin D–deficiency rickets	Vitamin D deficiency, phosphorus or calcium deficiency (rare), inadequate sunlight exposure, secondary to malabsorption syndromes (IBD, celiac disease, cystic fibrosis [rarely])	NA	Skeletal findings, abnormal gait, hypocalcemic tetany/seizures, developmental delay, failure to thrive	Replace the deficient nutrient orally; may need to administer vitamin D intramuscularly if rickets secondary to malabsorption.
Vitamin D–dependent rickets
Type I or pseudovitamin D–deficiency rickets	Deficiency of renal 25(OH) D3–1-α-hydroxylase	Autosomal recessive	Younger than two years, hypocalcemic tetany, severe bony changes, seizures	Calcitriol (Rocaltrol)
Type II or hereditary 1-α, 25-dihydroxyvitamin D–resistant rickets	Defective interaction between calcitriol and receptor	Autosomal recessive	Younger than one year, severe bony changes, alopecia	Massive doses of calcitriol and calcium
Vitamin D–resistant rickets
Familial hypophosphatemic rickets or X-linked hypophosphatemic rickets	Impaired proximal renal tubular reabsorption of phosphorus and inappropriately normal calcitriol levels	X-linked dominant	Short stature, leg bowing, dental abnormalities	Oral phosphate and calcitriol
Hereditary hypophosphatemic rickets with hypercalciuria	Impaired proximal renal tubular reabsorption of phosphorus and increased calcitriol	Autosomal recessive, autosoma dominant	Bone pain, muscular weakness	Oral phosphate
Miscellaneous
Renal rickets or renal osteodystrophy	Loss of functional renal parenchyma caused by chronic renal failure leads to mineral derangements and decreased calcitriol production	NA	Bone pain, arthralgias, fractures, muscle weakness, failure to thrive	Vitamin D and phosphate- binding compound
Rickets of prematurity	Multifactorial	NA	Osteopenia, fractures	Replace dietary deficiencies and minimize iatrogenic causes.
Tumor-induced or oncogenic rickets	Tumor-induced inhibition of renal 25(OH)D3–1-α-hydroxylase	NA	Fractures, bone pain, muscle weakness	Treat underlying malignancy.