Biomaterial Database

Friedreich's ataxia: point mutations and clinical presentation of compound heterozygotes. 1999

M Cossée, and A Dürr, and M Schmitt, and N Dahl, and P Trouillas, and P Allinson, and M Kostrzewa, and A Nivelon-Chevallier, and K H Gustavson, and A Kohlschütter, and U Müller, and J L Mandel, and A Brice, and M Koenig, and F Cavalcanti, and A Tammaro, and G De Michele, and A Filla, and S Cocozza, and M Labuda, and L Montermini, and J Poirier, and M Pandolfo

Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Hôpitaux Universitaires de Strasbourg, Illkirch, France.

Friedreich's ataxia is the most common inherited ataxia. Ninety-six percent of patients are homozygous for GAA trinucleotide repeat expansions in the first intron of the frataxin gene. The remaining cases are compound heterozygotes for a GAA expansion and a frataxin point mutation. We report here the identification of 10 novel frataxin point mutations, and the detection of a previously described mutation (G130V) in two additional families. Most truncating mutations were in exon 1. All missense mutations were in the last three exons coding for the mature frataxin protein. The clinical features of 25 patients with identified frataxin point mutations were compared with those of 196 patients homozygous for the GAA expansion. A similar phenotype resulted from truncating mutations and from missense mutations in the carboxy-terminal half of mature frataxin, suggesting that they cause a comparable loss of function. In contrast, the only two missense mutations located in the amino-terminal half of mature frataxin (D122Y and G130V) cause an atypical and milder clinical presentation (early-onset spastic gait with slow disease progression, absence of dysarthria, retained or brisk tendon reflexes, and mild or no cerebellar ataxia), suggesting that they only partially affect frataxin function. The incidence of optic disk pallor was higher in compound heterozygotes than in expansion homozygotes, which might correlate with a very low residual level of normal frataxin produced from the expanded allele.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D002648	Child	A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.	Children
D002675	Child, Preschool	A child between the ages of 2 and 5.	Children, Preschool,Preschool Child,Preschool Children
D002874	Chromosome Mapping	Any method used for determining the location of and relative distances between genes on a chromosome.	Gene Mapping,Linkage Mapping,Genome Mapping,Chromosome Mappings,Gene Mappings,Genome Mappings,Linkage Mappings,Mapping, Chromosome,Mapping, Gene,Mapping, Genome,Mapping, Linkage,Mappings, Chromosome,Mappings, Gene,Mappings, Genome,Mappings, Linkage
D004252	DNA Mutational Analysis	Biochemical identification of mutational changes in a nucleotide sequence.	Mutational Analysis, DNA,Analysis, DNA Mutational,Analyses, DNA Mutational,DNA Mutational Analyses,Mutational Analyses, DNA
D005260	Female		Females
D005621	Friedreich Ataxia	An autosomal recessive disease, usually of childhood onset, characterized pathologically by degeneration of the spinocerebellar tracts, posterior columns, and to a lesser extent the corticospinal tracts. Clinical manifestations include GAIT ATAXIA, pes cavus, speech impairment, lateral curvature of spine, rhythmic head tremor, kyphoscoliosis, congestive heart failure (secondary to a cardiomyopathy), and lower extremity weakness. Most forms of this condition are associated with a mutation in a gene on chromosome 9, at band q13, which codes for the mitochondrial protein frataxin. (From Adams et al., Principles of Neurology, 6th ed, p1081; N Engl J Med 1996 Oct 17;335(16):1169-75) The severity of Friedreich ataxia associated with expansion of GAA repeats in the first intron of the frataxin gene correlates with the number of trinucleotide repeats. (From Durr et al, N Engl J Med 1996 Oct 17;335(16):1169-75)	Friedreich Disease,Hereditary Spinal Sclerosis,Sclerosis, Hereditary Spinal,Friedreich Familial Ataxia,Friedreich Hereditary Ataxia,Friedreich Hereditary Spinal Ataxia,Friedreich Spinocerebellar Ataxia,Friedreich's Ataxia,Friedreich's Disease,Friedreich's Familial Ataxia,Friedreich's Hereditary Ataxia,Friedreich's Hereditary Spinal Ataxia,Hereditary Spinal Ataxia, Friedreich,Hereditary Spinal Ataxia, Friedreich's,Ataxia, Friedreich,Ataxia, Friedreich Familial,Ataxia, Friedreich Hereditary,Ataxia, Friedreich Spinocerebellar,Ataxia, Friedreich's,Ataxia, Friedreich's Familial,Ataxia, Friedreich's Hereditary,Ataxias, Friedreich,Ataxias, Friedreich's Hereditary,Disease, Friedreich,Disease, Friedreich's,Familial Ataxia, Friedreich,Familial Ataxia, Friedreich's,Friedreich Ataxias,Friedreich's Hereditary Ataxias,Friedreichs Familial Ataxia,Friedreichs Hereditary Ataxia,Hereditary Ataxia, Friedreich,Hereditary Ataxia, Friedreich's,Hereditary Ataxias, Friedreich's,Hereditary Spinal Scleroses,Scleroses, Hereditary Spinal,Spinal Scleroses, Hereditary,Spinal Sclerosis, Hereditary,Spinocerebellar Ataxia, Friedreich
D006579	Heterozygote	An individual having different alleles at one or more loci regarding a specific character.	Carriers, Genetic,Genetic Carriers,Carrier, Genetic,Genetic Carrier,Heterozygotes
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000293	Adolescent	A person 13 to 18 years of age.	Adolescence,Youth,Adolescents,Adolescents, Female,Adolescents, Male,Teenagers,Teens,Adolescent, Female,Adolescent, Male,Female Adolescent,Female Adolescents,Male Adolescent,Male Adolescents,Teen,Teenager,Youths