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What is Retinitis pigmentosa is a feature of all except and explain in detail?
Ans is 'b' i.e. Hallervorden-Spatz disease Retinitis pigmentosa is associated with many systemic conditions. These are important as they may be recognized first by an ophthalmologist.Systemic conditions associated with retinitis pigmentosa (RP)-Bardet-Biedl syndrome: It is characterized principally by retinitis pigmentosa, obesity, polydactyly, mental retardation, hypogonadism, and renal dysfunction.Laurence-Moon-Biedl syndrome: similar to Bardet-Biedl syndrome. In addition to Bardet Biedl syndrome has paraplegia.Usher's syndrome: RP & labyrinthine deafnessBassen-Kornzweig disease (Abetalipoproteinemia) : RP, fat malabsorption, spinocerebellar degeneration, and acanthocytosisKearns-Sayer syndrome: Mitochondrial myopathy characterized by external ophthalmoplegia, lid ptosis, cardiac conduction block & mild RP.Cockayne's syndrome: RP, progressive infantile deafness, dwarfism, mental retardation, nystagmus & ataxia.Refsum's syndrome: RP, peripheral neuropathy, cerebellar ataxia. (This is an autosomal recessive hypertrophic neuropathy caused by defective oxidation of phytanic acid, a branched-chain fatty acid found in dairy products, beef, lamb, and fish. The onset is in late childhood or adolescence, with a slowly progressive course of a sensorimotor demyelinating neuropathy with sensorineural deafness, cerebellar ataxia, and anosmia. Retinitis pigmentosa presenting as night blindness often precedes the onset of neuropathy)Hallgren fs syndrome: RP, vestibulo-cerebellar ataxia, congenital deafness & mental deficiencyNeuronal Ceroid Lipofuscinosis: is a devastating condition that involves progressive neurological failure, mental deterioration, seizures, and retinitis pigmentosa. It results from excessive accumulation of lip pigments (lipofuscin) in the body's tissues.Olivopontocerebellar degenerationNARP: Neuropathy, ataxia, retinitis pigmentosa, developmental delay, mental retardation, lactic academia (Ref: Harrison chapter e39)This list has been compiled from the above mention books. Hallervorden-Spatz finds no mention in these books. However on the below mentioned web-addresses, associations have been described with RP.(http://www.ncbi.nlm.nih.gov/pubmed/!734303; http://www.ncbi.nlm.nih.gov/pubmed/7898702)