| ataxia-telangiectasia | <neurology, oncology> An intriguing autosomal recessive disorder in which a single defective gene produces myriad and protean effects, presents with cerebellar ataxia, telangiectasias in the eyes and skin, immune deficiency and autoimmune phenomena, propensity for lymphoid and other malignancies, excessive sensitivity to ionising radiation, increased serum alpha-fetoprotein concentrations and a tendency for chromosome breakage and translocation. A syndrome characterised by choreoathetosis beginning in childhood, progressive cerebellar ataxia, telangiectasis of conjunctiva and skin, slowly progressive mental deterioration and increasing cerebellar degeneration. There is evidence that heterozygotes show an increased susceptibility to malignancy as well, with breast cancer often cited. The gene was localised by linkage studies to chromosome 11q22-23, and recently cloned, revealing it to be homologous to the PI-3 kinase family so that prenatal diagnosis by RFLP analysis is possible. Other related genes are suspected to exist. Diagnosis in affected patients is made on clinical grounds, by detection of high concentrations of alpha-fetoprotein, and by a specialised cell culture assay for radiosensitivity and atypical radioresistant DNA synthesis. These cell culture methods are also used for prenatal diagnosis. A characteristic autopsy feature of ataxia-telangiectasia is the presence of empty basket cells in the cerebellum which results from degeneration of the previously contained Purkinje cells. Inheritance: autosomal recessive. (16 Dec 1998) |
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| ataxia telangiectasia syndrome | ataxia telangiectasia |
| bovine congenital ataxia | An autosomal recessive ataxia seen in several European breeds of cattle. (05 Mar 2000) |
| Briquet's ataxia | Weakening of the muscle sense and increased sensibility of the skin, in hysteria. Synonym: hysterical ataxia. (05 Mar 2000) |
| Bruns ataxia | Difficulty in initiation of movements of the feet when they are in contact with the ground; a condition related to a frontal lobe lesion. (05 Mar 2000) |
| vasomotor ataxia | A form of autonomic ataxia causing irregularity in the peripheral circulation, marked by alternations of pallor and suffusion, due to spasm of the smaller blood vessels. (05 Mar 2000) |
| Marie's ataxia | An obsolete term for a variety of non-Friedreich hereditary ataxias. (05 Mar 2000) |
| vestibulocerebellar ataxia | Ataxia due to disease of the central vestibular system or its cerebellar components, manifested clinically by an unsteady gait, nystagmus, and incoordination of arm and leg movements. (05 Mar 2000) |
| respiratory ataxia | Completely irregular breathing pattern, with continually variable rate and depth of breathing; results from lesions in the respiratory centres in the brainstem, extending from the dorsomedial medulla caudally to the obex. Synonym: ataxic breathing, Biot's breathing, respiratory ataxia. (05 Mar 2000) |
| cerebellar ataxia | Loss of muscle coordination caused by disorders of the cerebellum. (05 Mar 2000) |
| chronic ataxia | Persistent ataxia, most often caused by hereditary cerebellar or metabolic disorders. (05 Mar 2000) |
| moral ataxia | Inconstancy of ideas and of conscious intent, as a manifestation of hysteria. (05 Mar 2000) |
| motor ataxia | Ataxia developing upon attempting to perform coordinated muscular movements. Synonym: kinetic ataxia. (05 Mar 2000) |
| hereditary ataxia | A simple autosomal recessive trait in fox terrier dogs that produces a progressive general ataxia. (05 Mar 2000) |
| hereditary cerebellar ataxia | A disease of later childhood and early adult life, marked by ataxic gait, hesitating and explosive speech, nystagmus, and sometimes optic neuritis. It probably comprises several distinct conditions with diverse patterns of inheritance. Collective term for a number of hereditary disorders in which cerebellar signs are the most prominent finding. (05 Mar 2000) |