Metabolic Disorders

Question 1

What is Marfan syndrome?

Answer 1

Autosomal dominant mesodermal dysplasia due to mutation in the FBN1 gene

Question 2

What are the ocular features in Marfan syndrome?

Answer 2

• lens displaced upwards & temporally due to weakened zonules
• myopia
• blurred vision

Question 3

What are the 2 forms of galactosemia?

Answer 3

1. Classical = deficiency of galactose 1 phosphate uridyl transferase (GPUT)
2. Deficiency of galactokinase (GK)

Question 4

What ocular features of galactosemia?

Answer 4

Galactosemic cataract = bilateral (oil droplet central lens opacities)

Question 5

What is Homocystinuria?

Answer 5

Autosomal recessive inborn errors of metabolism due to deficincy of cystathionine beta synthase enzymes which leads to accumulation of homocysteine & methionine

Question 6

What are the ocular features in Homocystinuria?

Answer 6

• ectopia lentis
• downward dislocation/subluxation of lens
• myopia
• glaucoma
• optic atrophy
• retinal detachment
• cataract

Question 7

What is Wilson disease?

Answer 7

Autosomal recessive, accumulation of copper in body

Question 8

What is the ocular features of Wilson disease?

Answer 8

1. Kayser fleischer ring
2. Sunflower cataract

Question 9

What is Kayser Fleischer ring?

Answer 9

Golden brown rings seen in periphery of eye due to copper accumulation at the descemet membrane

Question 10

What is sunflower cataract?

Answer 10

Golden plaque deposition due to accumulation of copper under posterior capsule of lens

Question 11

What is the pathogenesis of thyroid eye disease?

Answer 11

1. Adipogenesis, fibroblast proliferation, glycosaminoglycans synthesis
2. Activated T-cell act on fibroblast adipocere lineage
3. Extraocular muscle enlarged due to edema, infialtration with round cells
4. Increased acid mucopolysaccharide in orbital soft tissue
5. Infiltration with lymphocytes, plasma cells, macrophages, mast cells