Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0086543 (cataract)
 29,165 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The classification of hereditary abnormalities of iron metabolism was recently expanded and diversified. Genetic hemochromatosis now corresponds to six diseases, namely classical hemochromatosis HFE 1; juvenile hemochromatosis HFE 2 due to mutations in an unidentified gene on chromosome 1; hemochromatosis HFE 3 due to mutations in the transferrin receptor 2 (TfR2); hemochromatosis HFE 4 caused by a mutation in the H subunit of ferritin; and hemochromatosis HFE 6 whose gene is hepcidine (HAMP). Systemic iron overload is also associated with aceruloplasminemia, atransferrinemia and the "Gracile" syndrome caused by mutations in BCS1L. The genes responsible for neonatal and African forms of iron overload are unknown. Other genetic diseases are due to localized iron overload: Friedreich's ataxia results from the expansion of triple nucleotide repeats within the frataxin (FRDA) gene; two forms of X-linked sideroblastic anemia are due to mutations within the delta aminolevulinate synthetase (ALAS 2) or ABC-7 genes; Hallervorden-Spatz syndrome is caused by a pantothenate kinase 2 gene (PANK-2) defect; neuroferritinopathies; and hyperferritinemia--cataract syndrome due to a mutation within the L-ferritin gene. In addition to this wide range of genetic abnormalities, two other features characterize these iron disorders: 1) most are transmitted by an autosomal recessive mechanism, but some, including hemochromatosis type 4, have dominant transmission; and 2) most correspond to cytosolic iron accumulation while some, like Friedreich's ataxia, are disorders of mitochondrial metabolism.
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PMID:[Genetics of hereditary iron overload]. 1550 16

Since the early days of mitochondrial medicine, it has been clear that optic atrophy is a very common and sometimes the singular pathological feature in mitochondrial disorders. The first point mutation of mitochondrial DNA (mtDNA) associated with the maternally inherited blinding disorder, Leber's hereditary optic neuropathy (LHON), was recognized in 1988. In 2000, the other blinding disorder, dominant optic atrophy (DOA) Kjer type, was found associated with mutations in the nuclear gene OPA1 that encodes a mitochondrial protein. Besides these two non-syndromic optic neuropathies, optic atrophy is a prominent feature in many other neurodegenerative diseases that are now recognized as due to primary mitochondrial dysfunction. We will consider mtDNA based syndromes such as LHON/dystonia/Mitochondrial Encephalomyopahty Lactic Acidosis Stroke-like (MELAS)/Leigh overlapping syndrome, or nuclear based diseases such as Friedreich ataxia (mutations in FXN gene), deafness-dystonia-optic atrophy (Mohr-Tranebjerg) syndrome (mutations in TIMM8A), complicated hereditary spastic paraplegia (mutations in SPG7), DOA "plus" syndromes (mutations in OPA1), Charcot-Marie-Tooth type 2A (CMT2A) with optic atrophy or hereditary motor and sensory neuropathy type VI (HMSN VI) (mutations in MFN2), and Costeff syndrome and DOA with cataract (mutations in OPA3). Thus, genetic errors in both nuclear and mitochondrial genomes often lead to retinal ganglion cell death, a specific target for mitochondrial mediated neurodegeneration. Many mechanisms have been studied and proposed as the bases for the pathogenesis of mitochondrial optic neuropathies including bioenergetic failure, oxidative stress, glutamate toxicity, abnormal mitochondrial dynamics and axonal transport, and susceptibility to apoptosis.
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PMID:Retinal ganglion cell neurodegeneration in mitochondrial inherited disorders. 1926 52