The commonest autosomal recessive inherited lysosomal storage disorder is?

Appeared in: MNS 2024

Explanation

Gaucher disease is the most prevalent lysosomal storage disorder with an autosomal recessive inheritance pattern.
It is caused by a deficiency of the enzyme glucocerebrosidase, leading to the accumulation of a fatty substance called glucocerebroside.
This accumulation occurs in cells of the mononuclear phagocyte system (macrophages), which become enlarged and are known as 'Gaucher cells'.
Key clinical signs include enlargement of the spleen and liver (hepatosplenomegaly), low blood counts (pancytopenia), and bone problems.

Option B: This is also an autosomal recessive lysosomal storage disorder but is less common than Gaucher disease. It involves the accumulation of sphingomyelin.
Option C: This is another autosomal recessive lysosomal storage disorder, but it is rarer than Gaucher disease in the general population, though more frequent in specific ethnic groups like Ashkenazi Jews. It involves the accumulation of GM2 ganglioside.
Option D: This is a congenital vascular disorder, not a metabolic or lysosomal storage disease. It is characterized by port-wine stains, abnormal veins, and limb overgrowth.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Epidemiology and classification of lysosomal storage disorders as background academic context rather than a clinical decision trigger.
Nurses should be aware of the classic signs of Gaucher disease, such as unexplained splenomegaly, anemia, thrombocytopenia, and bone pain, to facilitate early diagnosis and referral.
Enzyme Replacement Therapy (ERT) is a key treatment for Gaucher disease, and nurses play a vital role in administering these intravenous infusions and managing patient care.
Genetic counseling is crucial for affected families due to the autosomal recessive inheritance pattern, helping them understand the risk (25% for each pregnancy) for future children.

How to Approach the Question

First, identify the key terms in the question: 'commonest', 'autosomal recessive', and 'lysosomal storage disorder'.
Second, evaluate each option against these criteria. Recognize that options A, B, and C are all lysosomal storage disorders with autosomal recessive inheritance.
Third, eliminate Klippel-Trenaunay syndrome because it belongs to a completely different category of disease (a congenital vascular disorder), not a metabolic one.
Fourth, compare the prevalence of the remaining options (Gaucher, Niemann-Pick, Tay-Sachs). Recall from your knowledge of genetic disorders that Gaucher disease is the most common among them in the general population.

Concept Tested & Keywords

Concept Tested: Epidemiology and classification of lysosomal storage disorders.
Stem keywords: commonest, autosomal recessive, inherited, lysosomal storage disorder
Lead-in keywords: is

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E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 165-167

Practise the full MNS 2024

Attempt every question from this paper in a timed mock, then review the full solution for each one.