A couple and some of their relatives are screened for Gaucher disease in a community-based screening program. The woman is homozygous for the dominant allele, represented by G. The woman's father, sister, and paternal grandmother are heterozygous carriers of the mutant allele, represented by g. Her paternal grandfather, her mother, and both of her mother's parents are homozygous for the dominant allele. The man is heterozygous and he has a brother with Gaucher disease. The man's parents and grandparents have not been tested, but it is known that none of them has Gaucher disease.
Draw a pedigree of this family, including the woman, the man, their siblings, parents, and grandparents.

Question

A couple and some of their relatives are screened for Gaucher disease in a community-based screening program. The woman is homozygous for the dominant allele, represented by G. The woman's father, sister, and paternal grandmother are heterozygous carriers of the mutant allele, represented by g. Her paternal grandfather, her mother, and both of her mother's parents are homozygous for the dominant allele. The man is heterozygous and he has a brother with Gaucher disease. The man's parents and grandparents have not been tested, but it is known that none of them has Gaucher disease.
Draw a pedigree of this family, including the woman, the man, their siblings, parents, and grandparents.

Draw a pedigree of this family, including the woman, the man, their siblings, parents, and grandparents.

Accepted Answer

Hi, everybody. Let's take a look at this practice problem together. Gauthier disease is caused by mutations in the blake that provide instructions for making an enzyme called glucocerebrosidase. Well, what is the function of glucocerebrosidase? Recall that it breaks down lipids. So, a mutation in a gene that causes Gauche disease will cause lipid accumulation in parts of the body that leads to organ dysfunction and other symptoms. So what is this mutation? Let's take a look at the answer options. A CBS gene. Now, the CBS gene codes for an enzyme called cysto thine beta synthes. This enzyme catalyzes amino acid reactions and is not involved in lipid reactions. So A is not the correct answer. Now, let's discuss both CND. So C the MTRR gene codes for an enzyme called methionine synthesis reductase. MTR gene codes for methionine synthes. Both of these enzymes are involved in catalyzing reactions for the methylation cycle. So, neither C nor D are the correct answer. The correct answer is option B, the GB A G, the GB A gene codes for that enzyme glucocerebrosidase and recall that that breaks down lipids. So, a mutation in the GB A gene causes Gauthier disease. So, b is the correct answer? All right. Everybody. I hope you found this helpful and I'll see you soon for the next practice problem.

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Key Concepts

Mendelian Inheritance and Allele Notation

Autosomal Recessive Inheritance Pattern

Pedigree Construction and Interpretation