Update on lysosomal acid lipase deficiency: Diagnosis, treatment and patient management

Twice weekly dosing with Sebelipase alfa (Kanuma®) rescues severely ill infants with Wolman disease

BACKGROUND

Sebelipase alfa (Kanuma®) is approved for patients with Wolman disease (WD) at a dosage of 3-5 mg/kg once weekly. Survival rates in the second of two clinical trials was greater, despite recruiting more severely ill patients, probably related to higher initial and maximal doses. We aimed to evaluate the effective pharmacokinetics and pharmacodynamics of Sebelipase alfa when administered to patients with severe WD at 5 mg/kg twice weekly, an intensive regimen which was not assessed in the trials.

METHODS

We recruited 3 patients receiving Sebelipase alfa 5 mg/kg twice weekly. We measured LAL activity in leukocytes and plasma oxysterol concentration in two patients and LAL activity in fibroblasts in one patient. Clinical follow up was also assessed.

RESULTS

Analyses of LAL activity and oxysterols demonstrate that there is short-lived enzyme activity post-dosing which is associated with the release of stored lipids. Clinical data demonstrate that 5 mg/kg twice weekly dosing is well tolerated and effective.

CONCLUSION

5 mg/kg twice weekly dosing with Sebelipase alfa rescues severely ill infants with WD by increasing substrate clearance. There is biologically relevant lipid accumulation in the 'trough' periods before the next dosing, even with this intensive regimen.

Early Discovery of Children With Lysosomal Acid Lipase Deficiency With the Universal Familial Hypercholesterolemia Screening Program

Lysosomal acid lipase deficiency (LAL-D) is an autosomal recessive lysosomal storage disorder, caused by homozygous or compound heterozygous pathogenic variants in the LIPA gene. Clinically, LAL-D is under- and misdiagnosed, due to similar clinical and laboratory findings with other cholesterol or liver misfunctions. As a part of the Slovenian universal familial hypercholesterolemia (FH) screening, LAL-D is screened as a secondary condition among other rare dyslipidemias manifesting with hypercholesterolemia. Out of 669 children included, three were positive for a homozygous disease-causing splicing variant NM_000235.4: c.894G > A (NP_000226.2:p. Gln298Gln) in the LIPA gene (NG_008194.1). The mean age by the diagnosis of LAL-D was 9.8 ± 0.9 years. Moreover, all three LAL-D-positive children had an important elevation of transaminases and decreased activity of the lysosomal acid lipase enzyme. Abdominal MRI in all children detected an enlarged liver but a normal-sized spleen. In conclusion, universal FH screening algorithms with the confirmatory genetic analysis in the pediatric population enable also rare dyslipidemia detection at an early age. An important clinical criterion for differentiation between FH and the LAL-D-positive children has elevated transaminase levels (AST and ALT). In all three LAL-D positive children, an improvement in cholesterol and transaminase levels and steatosis of the liver has been seen after early treatment initiation.

Lipid metabolism and classification of hyperlipaemias

This chapter summarises, and updates, lipid metabolism. Both pathways, exogenous metabolisms route via the chylomicrons, and the endogenous pathway of very low-density lipoproteins (VLDL) and low-density lipoproteins (LDL). The reverse cholesterol metabolism will also be mentioned. It also includes the current classification of hyperlipidaemias or hyperlipoproteinaemias, with a reminder of the phenotype classification, and further developments of the aetiological classification. Both parts have updated references, with which knowledge of this vast subject can be expanded.

[Clinical experience with orphan drugs for rare metabolic diseases]

INTRODUCTION

Inborn errors of metabolism are a highly heterogeneous group of orphan diseases. Diet therapy and enzyme and coenzyme replacement are the most frequently used treatment. There are few patients and published studies about inborn errors of metabolism. The main objective of this study was to describe the effectiveness of orphan drugs in inborn errors of metabolism in paediatric patients.

MATERIAL AND METHODS

Retrospective descriptive study of 24 months on patients diagnosed with inborn errors of metabolism during childhood and who attended the pharmacy clinic or Day-Care Unit of a 630-bed general hospital.

RESULTS

The study included 15 patients with a median age of 17.8 years and were treated with nine different drugs: sapropterin, sodium phenylbutyrate, miglustat, velaglucerase, sebelipase, idursulfase, 5-hydroxytryptophan, succinate, and riboflavin. Nine different inborn errors of metabolism were observed: phenylketonuria, defects of the urea cycle, Gaucher, Nieman-Pick, Hunter's disease, along with acid lipase deficiency, and mitochondrial diseases. Orphan drugs used for the treatment of inborn errors of metabolism accounted for 1.3% of hospital drug costs. Some orphan drugs achieved asymptomatic patients, but others just produced a modest symptomatic improvement. Most patients showed good tolerance to the treatment.

CONCLUSIONS

Orphan drugs used in inborn errors of metabolism had an easy to manage toxicity profile, with many disparities in effectiveness. These drugs have a high economic impact. The cost-effectiveness ratio for orphan drugs is a controversial issue due to their high cost and the inconclusive clinical evidence.

An overview of deregulated lipid metabolism in nonalcoholic fatty liver disease with special focus on lysosomal acid lipase

Obesity and type 2 diabetes are frequently complicated by excess fat accumulation in the liver, which is known as nonalcoholic fatty liver disease (NAFLD). In this context, liver steatosis develops as a result of the deregulation of pathways controlling de novo lipogenesis and fat catabolism. Recent evidences suggest the clinical relevance of a reduction in the activity of lysosomal acid lipase (LAL), which is a key enzyme for intracellular fat disposal, in patients with NAFLD. In this review, we provided a comprehensive overview of the critical steps in hepatic fat metabolism and alterations in these pathways in NAFLD, with a special focus on lipophagy and LAL activity. During NAFLD, hepatic fat metabolism is impaired at several levels, which is significantly contributed to by impaired lipophagy, in which reduced LAL activity may play an important role. For further research and intervention in NAFLD, targeting LAL activity may provide interesting perspectives.

AISF update on the diagnosis and management of adult-onset lysosomal storage diseases with hepatic involvement

Lysosomal storage diseases (LSDs) are a heterogeneous group of inherited disorders caused by loss-of-function mutations in genes encoding for lysosomal enzymes/proteins. The consequence is a progressive accumulation of substrates in these intracellular organelles, resulting in cellular and tissue damage. The overall incidence is about 1/8000 live births, but is likely underestimated. LSDs are chronic progressive multi-systemic disorders, generally presenting with visceromegaly, and involvement of the central nervous system, eyes, the skeleton, and the respiratory and cardiovascular systems. The age at onset and phenotypic expression are highly variable, according to the specific enzymatic defect and tissues involved, the residual activity, and the disease-causing genotype. Enzyme-replacement therapies and substrate-reduction therapies have recently become available, leading to the improvement in symptoms, disease progression and quality of life of affected individuals. Liver involvement and hepatosplenomegaly are frequent features of LSDs and a hallmark of adult-onset forms, frequently leading to medical attention. LSDs should therefore be considered in the differential diagnosis of liver disease with organomegaly. The present document will provide a short overview of adult-onset LSDs with hepatic involvement, highlighting the specificities and systemic manifestations of the ones most frequently encountered in clinical practice, which may hint at the correct diagnosis and the appropriate treatment.

Lysosomal Acid Lipase Deficiency: Therapeutic Options

Lysosomal acid lipase (LAL) deficiency is a metabolic (storage) disorder, encompassing a severe (Wolman disease) and attenuated (Cholesterol ester storage disease) subtype; both inherited as autosomal recessive traits. Cardinal clinical features include the combination of hepatic dysfunction and dyslipidemia, as a consequence of cholesteryl esters and triglyceride accumulation, predominately in the liver and vascular and reticuloendothelial system. Significant morbidity can arise, due to liver failure and/or atherosclerosis; in part related to the severity of the underlying gene defect and corresponding enzyme deficiency. Diagnosis is based on demonstration of decreased LAL enzyme activity, complemented by analysis of the cognate gene defects. Therapeutic options include dietary manipulation and the use of lipid-lowering drugs. Sebelipase alfa, a recombinant enzyme replacement therapy, has garnered regulatory approval, following demonstration of improvements in disease-relevant markers and clinical benefit in clinical trials, which included increased survival in the most severe cases.

Initial assessment and ongoing monitoring of lysosomal acid lipase deficiency in children and adults: Consensus recommendations from an international collaborative working group

BACKGROUND

Lysosomal acid lipase (LAL) deficiency is an ultra-rare, progressive, autosomal recessive disorder. Functional mutations in LIPA, the gene that encodes LAL, result in accumulation of cholesteryl esters and triglycerides in hepatocytes and in the macrophages of the intestines, vascular endothelial system, and numerous other organs. LAL deficiency has a broad clinical spectrum; children and adults can present with dyslipidemia, liver enzyme elevations, hepatosplenomegaly, hepatic steatosis, liver fibrosis and/or cirrhosis, and vascular disease, which may lead to significant morbidity and premature mortality in some patients. Given the systemic involvement and the wide range of healthcare specialists who manage patients with LAL deficiency, there is a need for guidelines to assess and monitor disease involvement.

OBJECTIVES

To provide a set of recommendations for the initial assessment and ongoing monitoring of patients with LAL deficiency to help physicians in various disciplines effectively manage the disease based on the observed presentation and progression in each case.

METHODS

A group of internationally recognized healthcare specialists with expertise in clinical genetics, pathology, hepatology, gastroenterology, cardiology, and lipidology convened to develop an evidence-based consensus of best practices for the initial assessment and ongoing monitoring of children and adults with LAL deficiency, regardless of treatment status; infants with LAL deficiency have been excluded from these guidelines because they require specialized care.

RESULTS

The authors present guidance for the assessment and monitoring of patients with LAL deficiency based on age and disease manifestations that include the hepatic, cardiovascular, and gastrointestinal systems. A schedule for ongoing monitoring of disease progression is provided. In addition, the need to establish an interdisciplinary and integrated care team to optimize the approach to managing this systemic disease is highlighted.

CONCLUSIONS

There is currently no published guidance on the assessment and monitoring of patients with LAL deficiency. These consensus recommendations for the initial assessment and ongoing monitoring of children and adults with LAL deficiency are intended to help improve the management of these patients.

Evaluation of two approaches to lysosomal acid lipase deficiency patient identification: An observational retrospective study

BACKGROUND AND AIMS

Lysosomal acid lipase deficiency (LALD) leads to the accumulation of cholesteryl esters and/or triglycerides (TG) in lysosomes due to the lack of the enzyme codified by the LIPA gene. The most common symptoms are dyslipidaemia and hypertransaminasemia, together with manifestations common to other lysosomal storage disorders (LSDs), including visceromegalies and elevated plasma biomarkers. Alteration of the lipid-liver profile (LLP) has been widely applied as a criterion for LALD screening, but the usefulness of biomarkers has not yet been explored. Our purpose was to explore the utility of plasma chitotriosidase activity (ChT) and CCL18/PARC concentration in addition to LLP to identify LALD patients in an observational retrospective study of two different sample collections.

METHODS

Biological samples refining: Collection 1 (primary hypercholesterolemia suspected) included unrelated individuals with hyperlipidaemia and without LDLR, APOB and PCSK9 gene mutations (Set 1), and Collection 2 (LSD suspected) included individuals without definitive LSD diagnosis (Set 2). We assessed plasma LLP (total cholesterol and its fractions, TG concentration and transaminases activities), as well as plasma ChT and CCL18/PARC. All subjects with anomalous LLP and/or biomarker levels were LIPA sequenced.

RESULTS

Twenty-four subjects showed altered LLP and/or biomarkers. We identified two LALD patients (one homozygous and one compound heterozygous) and one carrier of a novel LIPA variant.

CONCLUSIONS

The measurement of plasma ChT and CCL18/PARC combined with LLP will be a useful approach to identifying LALD patients in retrospective LALD patient studies.

Diagnostic Algorithm for Cholesteryl Ester Storage Disease: Clinical Presentation in 19 Polish Patients

BACKGROUND

Lysosomal acid lipase deficiency (LAL-D) is a rare autosomal recessive lysosomal lipid storage disorder that results in an early-onset, severe, and lethal phenotype, known as Wolman disease, or a late-onset, attenuated phenotype, cholesteryl ester storage disease (CESD). The aim of our study was to describe the clinical presentation of CESD, focusing on the first noted abnormalities in patients. A diagnostic algorithm of CESD was also proposed.

METHODS

This is an observational, 1-center study of 19 Polish patients with late-onset LAL-D.

RESULTS

The mean age at which the first symptoms were reported was 4 years and 6 months. A mild hepatomegaly was the most common initial abnormality observed in all (100%) patients. Seven (37%) patients were noted to have mildly to moderately elevated serum transaminases. At the time of first hospitalization all (100%) patients presented with hepatomegaly, 15 (79%) patients presented with elevated serum transaminases and all (100%) patients had dyslipidemia. The mean age at the time of CESD diagnosis was 7 years and 2 months. Diagnoses were based on a deficient LAL activity in leukocytes (in all patients) and the LIPA gene mutations (in 47% of them). All the patients were carriers for the mutation c.894G>A in the LIPA gene. There was approximately a 3-year delay from initial symptoms to final diagnosis.

CONCLUSIONS

Hepatomegaly constitutes the most common presenting clinical sign of CESD. Hepatomegaly and dyslipidemia defined as elevated serum total and LDL cholesterol, elevated triglycerides and normal to low HDL cholesterol, comprises the most characteristic findings at CESD diagnosis.

Lysosomal Acid Lipase Deficiency, a Rare Pathology: The First Pediatric Patient Reported in Colombia

BACKGROUND Lysosomal acid lipase deficiency is a rare genetic metabolic lipid storage disease, with a high morbidity, and mortality, in children and adults. It is characterized by a mutation in the LIPA gene that causes an alteration of lipid metabolism, resulting in deposits of cholesterol esters and triglycerides in organs such as the liver, blood vessels, and gastrointestinal tract. Lysosomal acid lipase deficiency is predominantly caused by the mutation c.894G>A, seen in approximately 50-70% of patients. Our objective is to report the first pediatric case of lysosomal acid lipase deficiency in a pediatric patient in Colombia. CASE REPORT The patient is a 14-year-old boy with isolated hepatomegaly since 6 years of age without a family history of dyslipidemia. In the pediatric control, laboratory exams revealed dyslipidemia, and a hepatic biopsy was performed, revealing severe fibrosis with septation and grade 3 microvesicular steatosis (>75%). He was referred to our center and was suspected to have lysosomal acid lipase deficiency. Enzymatic activity was measured, showing absent activity. Confirmatory diagnosis with genetic sequencing showed a pathological homozygous mutation of c.894G>A. CONCLUSIONS Lysosomal acid lipase deficiency can manifest as early- or late-onset, with variable and severe signs and symptoms. The late-onset form has a broad spectrum of manifestations with mild symptoms, leading to under-diagnosis, which increases the actual disease burden. Early diagnosis is essential to initiate enzyme replacement therapy, since the natural disease course can be changed. More studies should be conducted in Latin America to evaluate the prevalence of the disease.