Glucose tolerance and insulin release were evaluated in 16 families with Friedrich's ataxia. Impaired glucose tolerance differed in incidence according to the method of evaluation, but was increased in number in parents and siblings of Friedreich's cases. Insulin output was not quantitatively different from normal, although the insulin peak was often delayed. This finding, in association with i...

OBJECTIVE To analyze the production of antibodies to polysaccharide antigens in patients with ataxia-telangiectasia. PATIENTS AND METHODS We used the ELISA technique to measure the levels of IgG antibodies to serotypes 1, 3, 5, 6B, 9V and 14 of Streptococcus pneumoniae in 14 patients with ataxia-telangiectasia before and after immunization with 23-valent polysaccharide vaccine. Adequate respo...

Heterozygous mutations of KCNA1, the gene encoding potassium channel Kv1.1 subunits, cause episodic ataxia type 1 (EA1), which is characterized by paroxysmal cerebellar incoordination and interictal myokymia. Some mutations are also associated with epilepsy. Although Kv1.1-containing potassium channels play important roles in neuronal excitability and neurotransmitter release, it is not known h...

BACKGROUND Episodic ataxia (EA) is variably associated with additional neurologic symptoms. At least 4 genes have been implicated. Recently, a mutation in the SLC1A3 gene encoding the glutamate transporter EAAT1 was identified in a patient with severe episodic and progressive ataxia, seizures, alternating hemiplegia, and migraine headache. The mutant EAAT1 showed severely reduced uptake of glut...

The Mre11-Rad50-Nbs1 (MRN) complex plays critical roles in checkpoint activation and double-stranded break (DSB) repair. The Rad50 zinc hook domain mediates zinc-dependent intercomplex associations of MRN, which is important for DNA tethering. Studies in yeast suggest that the Rad50 zinc hook domain is essential for MRN functions, but its role in mammalian cells is not clear. We demonstrated th...

the hereditary ataxias comprise a wide spectrum of heterogeneous disorders that share three features: ataxia, involvement of cerebellum or its connections, and heritability. in many hereditary ataxias, the underlying gene mutations have been identified. knowledge of the causative mutations allows a rational classification of hereditary ataxias as autosomal recessive, autosomal dominant or mater...

UNLABELLED The mutation F184C in Kv1.1 leads to development of episodic ataxia type I (EA1). Although the mutation has been said to alter activation kinetics and to lower expression, we show here that the underlying molecular mechanisms may be more complex. Although F184 is positioned in the "peripheral" S1 helix, it occupies a central position in the 3D fold. We show in cut-open oocyte voltage...

Variants in CACNA1A that encodes the pore-forming α1-subunit of human voltage-gated Cav2.1 (P/Q-type) Ca(2+)channels cause several autosomal-dominant neurologic disorders, including familial hemiplegic migraine type 1, episodic ataxia type 2, and spinocerebellar ataxia type 6. To identify modifiers of incoordination in movement disorders, we performed a large-scale functional RNAi screen, using...

We describe the clinical and oculographic findings in 4 families with episodic ataxia and interictal nystagmus (EA-2) linked to chromosome 19p. Episodes varied from pure ataxia to combinations of symptoms suggesting involvement of the cerebellum, brainstem, and cortex. Some affected individuals exhibited a progressive ataxia syndrome phenotypically indistinguishable from the dominantly inherite...