title: Neurological disorders with autosomal dominant transmission.
abstract: Neurofibromatosis, Huntington's disease, and myotonic dystrophy are three hereditary disorders affecting the nervous system. They have in common the basic principles of autosomal dominant inheritance: an affected individual has one parent with the disorder; the disorder affects males and females in approximately equal numbers; and an affected individual has a 50 percent risk of transmitting the disorder to every child. Furthermore, each of the three disorders have additional features that complicate genetic counseling and decisions about reproduction. Neurofibromatosis has an extremely variable expressivity, making the identification of affected individuals difficult and allowing for some reduction in the risk figures; although there is a 50 percent risk of a child inheriting the mutant gene, only one-fourth to one-third of these will experience serious consequences. Huntington's disease has a fairly typical course with degeneration occurring over 10 to 20 years. The frequent late onset of the disorder and the lack of any preclinical test for detecting carriers create problems for those at risk who wish to have children but do not want to pass the disorder to future generations. Both variable expressivity and variable onset are found in myotonic dystrophy. In addition, there is a risk of the severe early onset myotonic dystrophy when the mother is the affected parent. Genetic counseling should be available to patients and families with these three disorders. Nurses who have an understanding of the dynamics of these particular disorders can be empathetic to patients who face personal and family problems caused by the conditions. Alert nursing staff, in casual discussion with patients, may learn of hereditary disorders in a family or may notice symptoms that could lead to diagnosis of one of these disorders. Finally, nurses who are aware of the variations in genetic transmission of these disorders, may be in position to instruct and reinforce genetic counseling that the family has received.
mesh_terms: D000328:Adult; D002648:Child; D002869:Chromosome Aberrations / Q000235:genetics*; D025063:Chromosome Disorders; D005260:Female; D005799:Genes, Dominant; D006580:Genetic Carrier Screening; D005817:Genetic Counseling; D006801:Humans; D006816:Huntington Disease / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000235:genetics; D009422:Nervous System Diseases / Q000235:genetics* / Q000451:nursing; D009456:Neurofibromatosis 1 / Q000235:genetics; D012657:Self-Help Groups