FISH EYE DISEASE (FED)

SCIENTIFIC BACKGROUND

Fish Eye Disease (FED) is a rare autosomal recessive disorder of the lipid metabolism caused by a partial dysfunction of the liver enzyme lecithin-cholesterol acyltransferase (LCAT). Patients with FED lack alpha-lcat activity (lcat activity that esterifies cholesterol in HDL), while preserving beta-lcat activity (lcat activity that esterifies cholesterol in other lipoproteins). Characteristic of FED is an extremely decreased serum concentration of HDL cholesterol (<10 mg/dl, hypoalphalipoproteinemia) accompanied by reduced cholesterol ester levels, resulting from a maturation disorder of HDL particles. LCAT plays an essential role in the maturation of HDL by providing cholesterol esters as core material for lipoproteins. The main target of LCAT is immature apoA-I-containing HDL particles.

Clinically, FED is characterized by corneal opacities causing the eyes of affected individuals to have the appearance of boiled fish eyes. Complete loss of function of the LCAT enzyme is referred to as classic LCAT deficiency and is characterized by mild reactive hypertriglyceridemia and glomerulosclerosis along with decreased HDL concentrations and corneal opacities. The latter can lead to renal failure requiring transplantation. An increased risk for coronary heart disease has been described for homozygous carriers of LCAT deficiency, but not for FED.

References

Vitali et al. 2017, Curr. Cardiol. Rep. 19:132 / Ramasamy I. 2016, Clin Chim Acta. 454:143 / Schaefer et al. 2016, Prog Cardiovasc Dis. 59:97 / Saeedi et al. 2015, Clin Biochem. 48:472