Question

I have been reading a paper that classifies genes in different groups by the type of disease-causing mutations. The categories of mutations (alleles) it gives are:

1.Haploinsufficient
2.Autosomal dominant
3.autosomal recessive
I was wondering what is the real difference between haploinsufficient and autosomal dominant.

As far as I know, a Haploinsufficient gene is the one that one copy LoF mutation produces the phenotype. This seems to be exactly the same as an Autosomal Dominant disease???

Can someone give me an example?

Answer 1

Haploinsufficient genes require one copy with a loss-of-function mutation to produce the phenotype, while autosomal dominant genes can be expressed even if they are heterozygous. An example of a haploinsufficient gene is FOXP2, while an example of an autosomal dominant disorder is Huntington's disease.

Step-by-step explanation:

The real difference between haploinsufficient and autosomal dominant is that a haploinsufficient gene only requires one copy with a loss-of-function mutation to produce the phenotype, while an autosomal dominant gene can be expressed even if it is heterozygous. In other words, a person with haploinsufficient gene will have the phenotype if one copy of the gene is mutated, whereas in autosomal dominant inheritance, one copy of the mutant gene is sufficient to cause the phenotype.

An example of a haploinsufficient gene is FOXP2. FOXP2 gene mutation is associated with language disorders, and individuals with one mutant copy of this gene will have impaired language abilities.

In contrast, an example of an autosomal dominant disorder is Huntington's disease. The mutant allele in this case produces an abnormal protein that is toxic to neural tissue, resulting in the disease phenotype. Even if a person only has one copy of the mutant allele, they will still develop Huntington's disease.