Symptoms of Friedreich's Ataxia
Brain 1981 Sep;104(3):589-620 Related Articles, OMIM, Books, LinkOut
Friedreich's ataxia: a clinical and genetic study of 90 families with an
analysis of early diagnostic criteria and intrafamilial clustering of
clinical feature. Harding AE.
The clinical features of 115 patients from 90 families with Friedreich's
ataxia are described. Onset of symptoms was before the age of 25 (mean
10.52) years in all the index cases. An analysis of early cases suggested
that limb and truncal ataxia and absent tendon reflexes in the
legs were the
only consistent diagnostic criteria within five years of presentation.
Dysarthria, signs of pyramidal tract dysfunction in the legs
and loss of
joint position and vibration sense are not necessarily present during the
first five years of symptoms, but appear to develop eventually in all cases.
Scoliosis and ECG evidence of cardiomyopathy
were found in over two-thirds
of the patients studied; pes cavus, distal amyotrophy, optic
atrophy,
nystagmus and deafness were
all less frequent. The disorder was gradually
progressive in all cases. The mean age of losing the ability to walk was 25
years; 95 per cent were chair-bound by the age of 44 years. About 10 per
cent of the patients had diabetes mellitus which was controlled by oral
hypoglycaemic drugs in one quarter.
Diabetes appeared to be associated with a higher incidence of optic atrophy
and deafness. Diabetes also clustered within sibships; the risk of an
individual with Friedreich's ataxia developing diabetes if an affected sib
has it is over 40 per cent. Similarly, cardiomyopathy ran true within
affected members of the same sibship, but there were instances of
discordance which suggest that the development of the non-neurological
features of Friedreich's ataxia may be controlled by modifying genes rather
than heterogeneity of the main gene. Segregation analysis and an increased
consanguinity rate amongst parents of patients (5.55 per cent) confirmed
that this disorder is of autosomal recessive inheritance. A study of 101
first degree relatives of the patients with Friedreich's ataxia failed to
demonstrate any neurological or electrocardiographic abnormalities which could be ascribed to the heterozygous state.
PMID: 7272714 [PubMed - indexed for MEDLINE]
