Question

Consider the pedigree below for Huntington’s disease, a rare neurodegenerative disorder. Is the disease allele most likely to be dominant or recessive?

a. Dominant
b. Recessive
c. Dominance cannot be determined from this pedigree

Answer 1

Autosomal Dominant pattern of inheritance

Step-by-step explanation:

Huntington’s disease (HT) is neurological disorder characterised with loss of motor control with uncontrolled movements, degeneration of cognitive functions and emotional problems.it occurs from ages of 35-40,and lasts for 20 years after the onset. Is due to mutation in the HTT genes.

when an individual has a single mutant copy of of a gene that causes a disorder which manifests itself in the presence of non-mutant copy of the gene, such inheritance disorder is said to exhibit Autosomal Dominant.The presence non mutant copy is not enough to neutralized the effect of the mutant copy,Therefore if the mutant copy is inherited from the mother or father, its effects manifest,

HT, diseases is a particular example of this condition. The mutant HTT gene is inherited as mutant copy and is therefore regarded as autosomal dominant single-gene neurological conditions.

Mutation of HT is called triplets repeats.This is a unique mutation which involves the repetition of CAG-triplets codes in the inherited subject. The Number of the repeats of the gene is an indicator of when the disease will be manifested and the severity of this as detected by the genetic test.