Tay-Sachs Disease vs Niemann-Pick Disease: Lysosomal Storage Diseases
Tay-Sachs disease is an autosomal recessive disorder characterized by mental retardation, blindness, muscular weakness, lysosomes with onion skin, and the appearance of a cherry red spot on the macula. The enzyme deficient in Tay-Sachs disease is Hexosaminidase A. Hexosaminidase A is an enzyme that catalyzes GM2 ganglioside into GM3 ganglioside, and because hexosaminidase A enzyme is deficient in Tay-Sachs disease, GM2 gangliosides accumulate in the brain. Tay-Sachs disease is common in Ashkenazi Jewish patient populations.
Niemann-Pick disease is an autosomal recessive disorder characterized by progressive neurodegeneration, hepatosplenomegaly, foam cells, and cherry red spot on the macula. The enzyme deficient in Neimann-Pick disease is Spingomyelinase. Spingomyelinase is an enzyme that catalyzes the reaction to convert sphingomyelin into ceramide. Because spingomyelinase is deficient, spingomyelin accumulates.
Differences between Tay-Sachs Disease and Niemann-Pick Disease
1. Unlike patients with Niemann-Pick disease, Tay-Sachs disease patients do not have hepatosplenomegaly, or large liver.
2. Compared to Tay-Sachs disease, a defining symptom of Niemann-Pick disease is that patients with Niemann-Pick disease have foam cells or lipid-laden macrophages.
Histology: Tay-Sachs vs Niemann Pick Disease
3. The histology for diagnosing Tay-Sachs disease and Niemann-Pick disease also differs. Niemann-Pick disease’s histological diagnosis is most notable for its lipid laden macrophages. In other words, under the microscope and histology slides, doctors can see a patient’s macrophage with an unusual large amount of lipids inside them, known as foam cells. Unlike Niemann-Pick disease, Tay-Sachs disease is notable for its lysosomes with onion skin for histology – literally, the lysosomes in the cells look like onions with multiple circular peel layers in it!
4. Tay-Sachs disease is unique and common in patients with Ashkenazi Jewish descent.
Summary of Differences: Tay-Sachs Disease vs Niemann-Pick Disease
|Tay-Sachs Disease||Niemann-Pick Disease|
|Symptom: No enlarged liver||Symptom: Yes, enlarged liver|
|Histology: No foam cells||Histology: Yes, foam cells and lipid-laden macrophages|
|Histology: Yes, lysosomes with onion skin||Histology: No lysosomes with onion skin|
|Enzyme: Gangliosidase||Enzyme: Sphingomyelinase|
|Accumulated Substrate: GM2 Ganglioside||Accumulated Substrate: Sphingomyelin|
|Deficient Product: GM3||Deficient Product: Ceramide|
|Copyright 2019 Moosmosis|
USMLE Lysosomal Storage Diseases: Easy Table Chart on Tay-Sachs disease and Niemann-Pick Disease
Similarities between Tay-Sachs Disease and Niemann-Pick Disease
- Both Tay-Sachs Disease and Niemann-Pick Disease are lysosomal storage diseases, meaning there is an abnormal metabolic product because of a deficiency in one of the many lysosomal enzymes that would normally break down lipids.
2. Both Tay-Sachs Disease and Niemann-Pick DIsease patients have cherry-red spots on their maculas, as a symptom. Patients also both have progressive neurodegneration.
3. Another similarity is that the inheritance for both Tay-Sachs disease and Niemann-Pick disease is autosomal recessive.
Summary of Similarities: Tay-Sachs Disease and Niemann-Pick Disease
|Similarities between Tay-Sachs and Niemann-Pick Disease: USMLE Lysosomal Storage Diseases|
|Symptom: Cherry-red spot on macula eye|
|Symptom: Neuronal degeneration|
|Inheritance: Autosomal Recessive AR|
|Copyright 2019 Moosmosis|
First Aid USMLE Step 1 2019. Tao Le, Vikas Bhushan, Matthew Socha , Yash Chavda, et al.
Niemann Pick Disease – Genetics. https://ghr.nlm.nih.gov/condition/niemann-pick-disease
Tay-Sachs Disease – NIH. https://rarediseases.info.nih.gov/diseases/7737/tay-sachs-disease