Fabry disease

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Fabrite → favourite

Gaucher disease

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Because you are crying, you need a tissue paper to wipe tears.

Tay-Sachs disease

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Epidemiology: more common in the Ashkenazi Jewish population

Mnemonic

• Any diseases with a hyphen in the name will presents with Cherry-Red Macula.
  • Retinal Ganglion Cell Accumulation: In these diseases, the defective lysosomal enzymes lead to an accumulation of undigested substrates (like lipids) within the cells, including the ganglion cells of the retina.
  • Macular Opacity: The ganglion cell layer is particularly thick in the macula, the central part of the retina responsible for sharp, detailed vision. The buildup of these materials in the ganglion cells around the fovea makes this area appear pale or opaque.
  • Foveal Contrast: The fovea centralis, the very center of the macula, is extremely thin and lacks ganglion cells. It derives its blood supply from the choroid, not the retinal circulation. Therefore, it’s not affected by the storage material accumulation in the same way.
  • Cherry-Red Appearance: Because the surrounding area becomes pale due to the accumulated substances, the unaffected fovea maintains its normal reddish appearance (due to the underlying choroidal blood supply), creating a contrasting “cherry-red spot” in the center.

Niemann-Pick disease

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Sphinger → finger

Krabbe disease

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World → Galaxy → Gala

Hunter syndrome & Hurler syndrome

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Mnemonic

1. X → X link recessive
2. The gun touches the hunter’s derm → Heparan sulfate, dermatan sulfate.
3. Hunter doesn’t have corneal cloudy → or he couldn’t see targets
4. Hunters are aggressive

• Hurler syndrome
  • Severe developmental delay & intellectual disability
  • Coarse facial features (eg, frontal bossing, broad nose, flat midface)
  • Corneal clouding
  • Hepatosplenomegaly
  • Death at age <10 (cardiac complications)
• Hunter syndrome
  • Milder features than Hurler:
    • (+) Aggressive behavior
    • (−) Corneal clouding
  • Death in adolescence/early adulthood

Metachromatic leukodystrophy

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1. Metapod can’t walk, can’t say, can demyelinate to butterfly

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Tip

Glycogen storage diseases > Pompe disease also affects lysosome.

I-cell disease

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• Definition: an autosomal recessive disease caused by a defect in N-acetylglucosaminyl-1-phosphotransferase activity
• Pathophysiology
  • Defective N-acetylglucosaminyl-1-phosphotransferase → impaired phosphorylation of mannose residues of glycoproteins in the Golgi apparatus that should be transported to lysosomes (glycoproteins do not have mannose-6-phosphate) → extracellular secretion of these glycoproteins instead of delivery to lysosomes → inability to degrade lysosomal content → accumulation of abnormal lysosomal substances in the serum
• Clinical features
  • Coarse facial features
  • Corneal clouding: progresses to blindness
  • Gingival hyperplasia
  • Claw hand deformity
  • Kyphoscoliosis
  • Abnormal bone growth and restricted joint movements
  • Failure to thrive (growth failure by 2 years of age)
  • Developmental delay
• Diagnostics
  • Prenatal: low levels of N-acetylglucosamine-1-phosphodiesterase enzyme activity in amniotic fluid or chorionic villi
  • Postnatal
    • Increased plasma levels of lysosomal enzymes
    • Inclusion bodies in peripheral blood lymphocytes (I-cells)
    • Note: negative urinary glycosaminoglycans (compared with mucopolysaccharidoses)