A family consist of husband, wife and 2 children wife's father has huntington's chorea. Which statement is true:
Ans. is 'c' If the wife does not get disease till age 50 children are not affected Huntington's chorea is an autosomal dominant* disease. The age of onset is usually 4th or 5th decade. But if the child has inherited the disease from father, juvenile onset of the disease is seen.In the question the lady has inherited the disease from her father therefore she should have developed the disease at an early age. If she has not developed the disease by age of 50, most probably she has not inherited the disease and so obviously would not transmit the disease to her children.About option 'd'Huntington's disease occurs due to "expansion of CAG repeat in ORF of gene encoding Huntingtin" not d/t point mutation in gene, .About option 'b' -This statement is also true as Huntington's disease occurs usually in the fourth or fifth decade. But I would prefer to go with option 'c' if the same question is repeated with same options.Also KnowBasic pathology of HD is atrophy and loss of neuromas by the caudate nucleus and putamen* associated with variable cerebrocortical atrophy.Though inherited, the disease has its onset in adult life, usually in the 4th and 5th decade.It is characterized by chorea * due to basal ganglia involvement and dementia d/t cerebral cortex involvement (dementia is a late feature)
Chance of getting disease in child is 1:4
Can occur upto age of 50
If wife does not get disease till age 50 children are not affected.
Huntington's chorea is due to point mutation in gene.
C.N.S.