Which of the following diseases have an underlying mitochondrial abnormality-

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#1

Which of the following diseases have an underlying mitochondrial abnormality-

a) Krabbe’s disease
b) Fabry’s disease
c) Mitochondrial myopathy
d) Oncocytoma
e) Fanconi syndrome

1.ab
2.bc
3.bd
4.cd
5.ad

Explanation:

  • Until now, we have disucssed response of injury to a cell as a unit.
  • However, Injury to a cell is associated with
  1. Alteration in cell organelles or
  2. Alteration in cytoskeleton

Alteration in cell organelles

Important organelles, affected in cell injury are

  1. Lysosomes
  • Primary lysosomes are membrane-bound intracellular organelles that contain a variety of hydrolytic enzymes (hydrolases) including acid phosphatase, glucronidase, Sulfatase, ribonuclease and collegenase.
  • Primary lysosomes fuse with membrane bound vacuoles that contain mateial to be digested, fowling secondry lysosome or phagolysosomes.
  • Lysosomes are involved in the breakdown of phagocytosed material in one of two ways.
  1. Heterophagy → Digestion of materials ingested from outside the cell. It is most common in neutrophils and macrophages.
  2. Autophagy → Digestion of cells own components.
  • In some diseses cells sequester abnormal substances that cannot be completely metabolized by lysosomes
    → Lysosomal storage diseases.
  • Example are

Pompe disease , Fabry disease (option b), Metochromatic leukodystrophy

Tay - Sachs disease, Gaucher disease , Mucopolysaccharidosis

Sandhoff disease, Niamen pick disease, Mucolipoidosis

GM2-gangliosidosis, Fucosidosis & Mannosidosis , Wolman’s disease, Krabbe disease (option a)

  1. Mitochondria
  • As already explanined, mitochondrial dysfunction plays an important role in cell injury and apoptosis.
  • Abnormalities in mitochondria may also occur in some genetic disorders:-
  • Mitochondrial myopathy
  • Leber’s heriditary optic neuropathy
  • Kearns sayre syndrome (Ophthalmoplegia plus)
  • Myoclonic epilepsy with ragged red fibres syndrome
  • MELAS
  • In addition, certain bening tumors found in saliva!), gland (oncocytoma), thyroid, parathyroid and kidney consist of cells called oncocytes with abundant enlarged mitochondria, giving cells a distinctly easinophilic appearane.
  • 3. Induction (hypertrophy) of smooth endoplasmic reticulum
  • The smooth ER is involved in metabolism of certain drugs and chemicals.
  • These agents can cause hypertrophy of smooth ER as an adaptive response, eg. prolonged barbiturates use is associated with tolerance due to hypertrophy of smooth ER of hepatocytes, which metobolizes the drug.
    For cystoskeletal alteration see next explanation