Type 1 Fucosidosis Is a Rare Human Disease $\alpha$ -1-Fucosidase),and Is Inherited in an Autosomal Recessive Manner

Multiple Choice

Type 1 fucosidosis is a rare human disease.Patients cannot hydrolyze the disaccharide fucose,and as a result have severe neurological decline and die by age 6.The disease is due to a defect in the gene that encodes the lysosomal enzyme that breaks down fucose ( $\alpha$ -1-fucosidase) ,and is inherited in an autosomal recessive manner.Jane and John have a child who has Type 1 fucosidosis.What is the probability that their next child will also have the disease?

A) No chance
B) 1/4
C) 1/2
D) 3/4
E) 4/4 or 100%