Lysosomal acid lipase deficiency: a hidden disease among cohorts of familial hypercholesterolemia?

Highlights: - Dyslipidemia phenotype of patients with familial hypercholesterolemia and lysosomal acid lipase deficiency (LALD) can overlap; - Familial hypercholesterolemia negative patients should be investigated to identify possible LALD patients; - Correct identification of LALD patients is important for patient prognosis. Background: Lysosomal acid lipase deficiency (LALD) is an autosomal recessive disorder and an unrecognized cause of dyslipidemia. Patients usually present with dyslipidemia and altered liver function and mutations in LIPA gene are the underlying cause of LALD. Objective: The aim of this study was to investigate LALD in individuals with severe dyslipidemia and/or liver steatosis. Methods: Coding, splice regions, and promoter region of LIPA were sequenced by Sanger sequencing in a cohort of mutation-negative familial hypercholesterolemia (FH) patients (n = 492) and in a population sample comprising individuals with several types of dyslipidemia and/or liver steatosis (n = 258). Results: This study led to the identification of LALD in 4 children referred to the Portuguese FH Study, all with a clinical diagnosis of FH. Mild liver dysfunction was present at the age of FH diagnosis; however, a diagnosis of LALD was not considered. No adults at the time of referral have been identified with LALD. Conclusion: LALD is a life-threatening disorder, and early identification is crucial for the implementation of specific treatment to avoid premature mortality. FH cohorts should be investigated to identify possible LALD patients, who will need appropriate treatment. These results highlight the importance of correctly identifying the etiology of the dyslipidemia.