Ataxia telengiectasia

ATAXIA TELANGIECTASIA
Genetic map:
  • Gene involved – ATM gene on chromosome 11 which encodes Atm protein kinase, a member of phosphatidyl inositol 3-kinase family
  • only phacomatotic hereditary condition transmitted in the autosomal recessive mode, where combined immunodeficiency is associated with cerebellar ataxia, telangiectasia, ovarian dysgenesis & chromosomal abnormalities. 
Clinical and Histologic features:
  • Presents in the first decade of life with progressive telangiectatic lesions and ataxia & chorio-athetoid movements associated with deficits in cerebellar function and nystagmus Truncal and limb ataxia, dysarthria, extensor plantar responses, myoclonic jerks, areflexia, distal sensory deficits
  • Thymic hypoplasia, premature aging, Type 1 DM
  • ↑ incidence of recurrent pulmonary infections, lymphomas, Hodgkin's disease, acute T cell leukemia, breast cancer
  • Most striking neuropathologic changes:
  •  loss of Purkinje, granule and basket cells in the cerebellar cortex and neurons in the deep cerebellar nuclei
 Complication:
  • Death occurs due to sinopulmonary infection early in life , or malignancy in 2nd or 3rd decade.
Immunological features :
  • May affect T&B cells
  • IgA, IgE and IgG2 deficiency.
  • T cell function is variably depressed.
  • CMI is also defective resulting in impairment of delayed hypersensitivity & graft rejection. 
Treatment : Transfer factor therapy & fetal thymus transplants.
Exam Question

ATAXIA TELANGIECTASIA
  • Gene involved – ATM gene on chromosome 11 which encodes Atm protein kinase, a member of phosphatidyl inositol 3-kinase family
  • only phacomatotic hereditary condition transmitted in the autosomal recessive mode, where combined immunodeficiency is associated with cerebellar ataxia, telangiectasia, ovarian dysgenesis & chromosomal abnormalities. 
  • Presents in the first decade of life with progressive telangiectatic lesions and ataxia & chorio-athetoid movements associated with deficits in cerebellar function and nystagmus

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