Mutations in lysosomal acid lipase A (LIPA) result in two phenotypes depending on the extent of lysosomal acid lipase (LAL) deficiency: the severe, early-onset Wolman disease or the less severe cholesteryl ester storage disease (CESD). In CESD, the severity of the symptoms, hepatomegaly and hypercholesterolaemia, can be highly variable, presenting in childhood or adulthood. Therefore, it is likely that many patients are undiagnosed or misdiagnosed. Nevertheless, LAL deficiency has been recognized for more than 25 years, but adequate therapeutic strategies are limited.
CESD has an estimated prevalence of one in 90 000 to 170 000 individuals in the general population, confirming the likelihood that this disease is currently underdiagnosed. A number of studies have shown that in LIPA deficient patients the hypercholesterolaemic phenotype can be attenuated using statin therapy, and favourable effects on reduction of lipid accumulation in lysosomes have been reported. Targeting lysosomal exocytosis with LAL replacement therapy was shown to be successful in animal models and recently a phase I/II study demonstrated its safety and its potential metabolic efficacy on transaminase levels.
The hypercholesterolaemic phenotype in CESD can be difficult to distinguish from other known hypercholesterolaemic disorders. In the majority of CESD cases with hypercholesterolaemia favourable responses on statin treatment are observed, but the effect on reduction of lipid accumulation in lysosomes needs to be further evaluated. Combining statins with LAL replacement therapy may provide a promising approach for optimal treatment of LIPA deficiencies in the future.
Supplemental Digital Content is available in the text
aDepartment of Vascular Medicine
bDepartment of Experimental Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands
Correspondence to Sigrid W. Fouchier, PhD, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. Tel: +31 20 566 5899; fax: +31 20 691 6972; e-mail: firstname.lastname@example.org
Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Website (www.co-lipidology.com).