A 2-year-old boy, fourth child of a family of Pakistan immigrants was referred to Paediatric Department because of growth disturbance and swelling and pain of wrists and knees. The boy was a picky eater and was exclusively breastfed until 14 months of age. The parents did not give him supplements of vitamin D.
Laboratory investigation revealed: iron deficiency anaemia, hypocalcaemia, increased alkaline phosphatase concentrations, high levels of parathyroid hormone, low levels of 25-hydroxy-vitamin D.
The radiographs showed several skeletal abnormalities of growth plates: the distal radius and ulna typically demonstrate metaphyseal cupping and fraying, irregularity along the physeal margins of distal femurs and proximal tibias were also present. The chest plain X-ray shows discrete widening of the sternal ends of the ribs (Rachitic rosary) and irregularity of the proximal humeri.
Rickets is the bony manifestation of deficiency or impaired metabolism of vitamin
D (V.D.), calcium or phosphate. It occurs in children during bone growth, the adult form is called osteomalacia. 
The lack of these metabolites leads to insufficient mineralisation and build-up of non-ossified osteoid.
V.D. is absorbed from food or produced by the skin exposed to sunlight. An inadequate exposure to sunlight and a diet low of V.D. is the most common cause of this disease.
The rickets is rare in the industrialised nations, and is more frequently found in immigrants from underdeveloped countries where the disease is still common.
Infants breastfed for a long time and not supplemented with V.D. can develop this condition since breast milk does not provide the right amount of this vitamin. 
More rare causes are: genetic defects and several forms of kidney, liver and bowel diseases that affect the absorption and metabolism of vitamins and minerals.[3-4]
Signs and symptoms of rickets include growth retardation, short stature, bone pain, muscle weakness, delayed formation of teeth and dental deformities.
The softening of the growth plates of the ends of the bones can cause a number of skeletal deformities, including: abnormal of shaped skull (craniotabes), bowlegs, rib-cage abnormalities (rachitic rosary), breastbone projection (pigeon chest), curved spine, thickened wrists and ankles, pelvic, and spinal deformities. 
In very severe rickets, the patients may develop serious symptoms due to very low levels of calcium or phosphate, as tetany or seizures.
The rickets can be suspected clinically. X-rays of long bones and blood and urine tests can confirm the diagnosis and monitor the treatment.
For the treatment of nutritional rickets it is sufficient to correct the V.D. deficiency and ensure adequate calcium intake. Usually cholecalciferol is used, because it is more effective than ergocalciferol. In genetic forms of rickets, the defects of enzyme activity makes it necessary administer the active form of V.D. (Calcitriol) [3-4]. If the rickets occurs as a complication of another disease, treating the underlying condition will often cure the rickets. Some of the bony abnormalities may require surgical treatment.
Differential Diagnosis List
Hypophosphatemia Inherited or Acquired.