All are mitochondrial disorders except:

d. Fragile X Syndrome(Ref: Nelson's 20/e p 600-601, Ghai 8/e p 644)Mitochondrial Disorders, include Leber Hereditary Optic Neuropathy, MELAS (Mitochondrial encephalomyopathy, lactic acidosis, and stroke like episodes), MERRF(Myoclonic epilepsy, ragged red fibers) in muscle, & Pearson syndromeExamples of Mitochondrial Disorders (Mnemonic: K-L-M-N-O-P)DiseasePhenotypeKSSKearn-Sayre syndromeExternal ophthalmoplegia, heart block, retinal pigmentation, ataxiaLHONLeber hereditary optic neuropathyBilateral subacute or acute painless optic atrophyMELASMitochondrial encephalomyopathy, lactic acidosis, and stroke like episodes; may manifest only as diabetesMERRFMyoclinic epilepsy, ragged red fibres in muscle, ataxia, increased CSF protein, sensorineural deafness, dementiaNARPNeuropathy, Ataxia, Retinitis Pigmentosa, Leigh diseaseLoss of central vision leading to blindness in young adult lifeCPEOChronic progressive external OphthalmoplegiaBilateral ptosis, ophthalmoplegia & proximal muscle weaknessPearson syndromePancreatic insufficiency, pancytopenia, lactic acidosis