NCLEX Question for Non disjunction of a chromosome

NCLEX Review Question

Non disjunction of a chromosome results in which of the following diagnoses?

a.Down Syndrome
b.Huntington Disease
c.Duchenne Muscular Dystrophy
d.Marphan Syndrome

Correct Answer: A
Down Syndrome
Rationale: When a pair of chromosomes fails to separate completely and creates a sperm or oocyte that contains two copies of a particular chromosome (non disjunction) Down syndrome results from three number 21 chromosomes.

Huntington Disease
Rationale: Huntington disease is one example of a germ-line mutation.

Duchenne Muscular Dystrophy
Rationale: Duchenne muscular dystrophy, an inherited form of muscular dystrophy, is an example of a genetic caused by structural gene mutations.

Marphan Syndrome
Rationale: Marphan Syndrome is a genetic condition that may occur in a single family member as a result of spontaneous mutation.

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