OMIM ID:
Cerebral Amyloid Angiopathy
Alternate Names
Defective Genes
Clinical Characteristics
Ocular Features
Posterior polar cataracts appear during the third decade of life.
Systemic Features
Progressive hearing loss has its onset in the third decade and becomes severe in the 5th decade. Progressive dementia, often in the form of paranoid psychosis, begins about age 50. Cerebellar ataxia and intention tremor have their onset in midlife. There is a diffuse atrophy throughout the brain and cranial nerves are demyelinated. Blood vessels throughout the CNS, spinal cord and retina show an amyloid angiopathy. Intracranial hemorrhage is a significant risk and, when lobar in location, carries a significant risk of mortality within months. Death generally occurs in the 5th and 6th decades of life.
Genetics
Inheritance
Pedigree patterns in the few reported families are consistent with autosomal dominant inheritance. A mutation has been found in the ITM2B gene located at 13q14.
Pedigree
Autosomal dominant
Autosomal dominant disorders require only one mutation for the disease to be expressed. Since an affected parent has two chromosomes, only one of which has the mutant gene, parents can expect that half (50%) of their children will receive that one and inherit the disease. It is common for individuals that inherit the mutation, however, to not have evidence of the disease (nonpenetrance).
Autosomal dominant inheritance leads to a vertical pattern of transmission