D1 MTE2 Case 6: A child with metabolic myopathy

A 15-year-old boy, born to 3(rd) degree consanguineously married couple presented with complaints of abnormal waddling gait and outward bowing of legs since 1-year, joint pains and difficulty in climbing stairs since 6 months. Had normal developmental motor milestones and was of average height compared to peers. No h/o muscle pains. There was no symptomatic relief with vitamin D supplementation. On examination child had large low set ears, mal aligned teeth with widened wrists and ankles, double malleoli and genu varum. There was also evidence of proximal myopathy in the lower limbs. Initial investigations revealed serum calcium of 10.6 mg/dl, Po4 of 2 mg/dl, ALP 3322 IU/L, vitamin D3 10.2 ng/ml and serum PTH of 1448 pg/ml.