This rare inherited disorder, sometimes called familial Danish dementia, has so far been reported only in Denmark.
The signs and symptoms in this disorder appear in adults. Cataracts and deafness have their onset in the third decade of life. Dementia begins about age 50 and unsteadiness (ataxia) about the same time. Many patients have a tremor (fine, involuntary movements). These symptoms seem to result from deposition of foreign material (amyloid) in the blood vessels of the brain and spinal cord which leads to loss of neural tissue.
This seems to be an autosomal dominant disorder in which a gene mutation is passed directly from parent to child.
The diagnosis requires a multidisciplinary approach by neurologists and ophthalmologists. No treatment is available other than cataract surgery if necessary and most patients do not live beyond about the 5th or 6th decades.