Question

Huntington’s disease (HD) is an autosomal dominantly-inherited neurodegenerative disease that occurs often at the mid-age of patient, which is caused by a CAG repeat expansion at Htt gene. A patient was the first to be diagnosed as HD patient in his family, and his father died at his early 30s with an accident and his mother still lives at her 80s.  The patient married a healthy woman with no family history of HD, What is the likelihood that his adolescent son may show up with the disease symptom eventually?

		0%
		25%
		50%
		100%

Huntington’s disease (HD) is an autosomal dominantly-inherited neurodegenerative disease that occurs often at the mid-age of patient, which is caused by a CAG repeat expansion at Htt gene. A patient was the first to be diagnosed as HD patient in his family, and his father died at his early 30s with an accident and his mother still lives at her 80s. The patient married a healthy woman with no family history of HD, and if the genetic anticipation happens, will the symptoms happen earlier or later in his son's age compared to the father?

		earlier in the son
		later in the son
		about the same age
		It is no way to make such prediction

Answer 1

In autosomal dominant disease the carrier is affected 100% with diseased.

Father AA= disease

Mother =aa = normal

Carried Aa is also diseased.

AA aa

Offspring

Aa Aa Aa Aa

It tells is that children is 100% diseased.

2: Symptom will occur earlier in the son .

As Genetic anticipation is a phenomenon in which the signs and symptoms of genetic conditions become more severe and appear at an earlier age, as they are passed from one generation to the next.

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