Answer: The possible genotype for their child is Hh. All the children will be heterozygous for Huntington (Hh).
The possible phenotype for their child is Huntington disease.
Explanation: If H represents the trait for Huntington and h represents normal trait; and if Huntington trait (H) is dominant over normal trait (h), therefore the genotype of the mother who is homozygous for Huntington disease is HH and the genotype of the man who is homozygous normal is hh.
A cross between the man and woman will produce offsprings who are all heterozygous for Huntington disease Hh. Phenotypically, the offsprings will manifest as Huntington disease.
See the attached punnet square for more information
