Adult NCL is very rare although affected families have been described from several different countries. Adult NCL has often been called Kufs disease and doctors recognise two main types – called type A and type B. Unlike the childhood NCLs, vision is not affected in either type. In some families inheritance is recessive but in others a dominant inheritance pattern is seen. Until the genetic basis for the adult NCLs is fully understood, diagnosis is usually dependent on a brain biopsy. It is emerging that several genes can cause adult onset NCL diseases.
Type A presents in early adulthood with a progressive myoclonic epilepsy, ataxia and slow cognitive deterioration over many years.
Type B usually presents with an early dementia or evolving movement disorder.
Mild mutations in childhood NCL genes may also cause NCL disease with delayed age of onset and slow disease progression but vision is generally affected and abnormal storage is seen more reliably in peripheral tissues.
Dr Ruth Williams (NCL2012 Abstract Book, Clinical Summaries 2012)