Huntington's Disease

Huntington's disease (HD) "results from genetically programmed degeneration of brain cells, called neurons, in certain areas of the brain".The result is that the sufferer is less than normal stable in terms of 'emotions, intellectual capabilities and voluntary movements'.

HD is normally inherited within families, A mutation in a normal gene poses each child ( eg a single parent suffering from HD) , a 50-50 chance  of inheriting it.If a child does not inherit the HD gene, he or she will not develop the disease and cannot pass it to subsequent generations. An inheritor of the mutated gene will inherit HD in any time of his life. It is a totally mutually exclusive probability for every child of either inheriting or not inheriting the disease

A microscope image of Medium spiny neurons (yellow) with nuclear inclusions (orange), which occur as part of the disease process,

Some early symptoms of HD are "mood swings, depression, irritability or trouble driving, learning new things, remembering a fact, or making a decision. As the disease progresses, concentration on intellectual tasks becomes increasingly difficult and the patient may have difficulty feeding himself or herself and swallowing. "

The disease may progress/ develop in a person's life at any time, hence no specific criteria for that. HD is diagnosed via genetic tests, neurological and laboratory tests. Patient's medical history is also essential in diagnostic procedures. "Presymptomic testing is available for individuals who are at risk for carrying the HD gene. In 1 to 3 percent of individuals with HD, no family history of HD can be found".

Reference:www.news-medical.net