ERRATA: Gaucher and Neiman-Pick have Hepatosplenomegaly, but Tay-Sachs does NOT. The table below has been corrected and a note as been added to the appropriate part of the video. I also misspelled Hexosaminidase A in the powerpoint slide.
Sphigolipids are an important part of the cell membrane. However, when these lipids are improperly metabolized due to genetic disorders they build up in the lysosome causing problems. The collection of these diseases are called Sphigolipidosis, or Lysosomal Storage Diseases. If untreated these diseases can be lethal, but individuals often live long lives with proper enzyme replacement.We already covered I-Cell Disease, one example of a Lysosomal Storage Disease, in a previous section.
Tay-Sachs, Gaucher & Neiman-Pick are all Autosomal Recessive deficiencies of enzymes which are involved in the degradation of sphigolipids. When an enzyme in this pathway is deficient, the substrate for the enzyme builds up and causes problems. All 3 of these diseases are more common among Ashkenazi (Eastern European) Jews.
It can be tough to differentiate between different sphigolipidosis based solely on clinical presentation, because there is overlap in symptoms between the diseases. Thankfully the test writers usually aren’t that evil. Most questions on this topic will be very straight forward. You are probably going to see something like “It is this disease. Which enzyme is deficient?” or “This substrate is building up. What disease is it?”, but you might see a question that includes a clinical scenario so here are the basics.
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