Which of the following conditions show mitochondrial pattern of inheritance?

A. Chronic progressive external ophthalmoplegia

B. Myotonic dystrophy

C. Myoclonic epilepsy with ragged-red fibers

D. Leber’s hereditary optic neuropathy

E. Pearson’s syndrome

Answer

Chronic progressive external ophthalmoplegia, myoclonic epilepsy with ragged-red fibers (MERRF), Leber’s hereditary optic atrophy and Pearson’s syndrome are mitochondrial disorders. So, A, C, D and E are true.

Myotonic dystrophy is a autosomal dominant disorder, which occurs due to trinucleotide repeat expansions. Therefore, B is false.

Note

Mitochodrial disorders

• CPEO – chronic progressive external ophthalmoplegia
• KSS – Kearns-Sayre syndrome
• LHON – Leber hereditary optic neuropathy
• MELAS – mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes
• MERRF – myoclonic epilepsy with ragged-red fibers
• NARP – neurogenic weakness with ataxia and retinitis pigmentosa
• Pearson syndrome
• Leigh syndrome