We report a rare presentation of mitochondrial disorder in a child with rec
urrent carpopedal spasms due to hypocalcemia and hypomagnesemia, secondary
to renal proximal tubulopathy and possible hypoparathyroidism. At least two
mutant mitochondrial DNA species were identified, and abnormal mitochondri
a were found in the muscle and renal biopsy specimens. The case illustrates
the spectrum and diversity of mitochondrial presentations, arising because
of heteroplasmy of mutations and the type of organs affected.