Background—Mutations in the LCAT gene cause lecithin:cholesterol acyltransferase (LCAT) deficiency, a very rare
metabolic disorder with 2 hypoalphalipoproteinemia syndromes: classic familial LCAT deficiency (Online Mendelian
Inheritance in Man No. 245900), characterized by complete lack of enzyme activity, and fish-eye disease (Online
Mendelian Inheritance in Man No. 136120), with a partially defective enzyme. Theoretically, hypoalphalipoproteinemia
cases with LCAT deficiency should be at increased cardiovascular risk because of high-density lipoprotein deficiency
and defective reverse cholesterol transport.
Methods and Results—The extent of preclinical atherosclerosis was assessed in 40 carriers of LCAT gene mutations from
13 Italian families and 80 healthy controls by measuring carotid intima-media thickness (IMT). The average and
maximum IMT values in the carriers were 0.07 and 0.21 mm smaller than in controls (P0.0003 and P0.0027),
respectively. Moreover, the inheritance of a mutated LCAT genotype had a remarkable gene-dose– dependent effect in
reducing carotid IMT (P0.0003 for average IMT; P0.001 for maximum IMT). Finally, no significant difference in
carotid IMT was found between carriers of LCAT gene mutations that cause total or partial LCAT deficiency (ie, familial
LCAT deficiency or fish-eye disease).
Conclusions—Genetically determined low LCAT activity in Italian families is not associated with enhanced preclinical
atherosclerosis despite low high-density lipoprotein cholesterol levels. This finding challenges the notion that LCAT is
required for effective atheroprotection and suggests that elevating LCAT expression or activity is not a promising
therapeutic strategy to reduce cardiovascular risk.
