Lysosomal Acid Lipase Deficiency: Genetics, Screening, and Preclinical Study.

Lysosomal acid lipase (LAL) is a lysosomal enzyme essential for the degradation of cholesteryl esters through the endocytic pathway. Deficiency of the LAL enzyme encoded by the LIPA gene leads to LAL deficiency (LAL-D) (OMIM 278000), one of the lysosomal storage disorders involving 50-60 genes. Among the two disease subtypes, the severe disease subtype of LAL-D is known as Wolman disease, with typical manifestations involving hepatomegaly, splenomegaly, vomiting, diarrhea, and hematopoietic abnormalities, such as anemia. In contrast, the mild disease subtype of this disorder is known as cholesteryl ester storage disease, with hypercholesterolemia, hypertriglyceridemia, and high-density lipoprotein disappearance. The prevalence of LAL-D is rare, but several treatment options, including enzyme replacement therapy, are available. Accordingly, a number of screening methodologies have been developed for this disorder. This review summarizes the current discussion on LAL-D, covering genetics, screening, and the tertiary structure of human LAL enzyme and preclinical study for the future development of a novel therapy.

Lysosomal acid lipase deficiency in pediatric patients: a scoping review

Abstract Objective: Lysosomal acid lipase deficiency (LAL-D) is an underdiagnosed autosomal recessive disease with onset between the first years of life and adulthood. Early diagnosis is crucial for effective therapy and long-term survival. The objective of this article is to recognize warning signs among the clinical and laboratory characteristics of LAL-D in pediatric patients through a scope review. Sources: Electronic searches in the Embase, PubMed, Livivo, LILACS, Web of Science, Scopus, Google Scholar, Open Gray, and ProQuest Dissertations and Theses databases. The dataset included observational studies with clinical and laboratory characteristics of infants, children and adolescents diagnosed with lysosomal acid lipase deficiency by enzyme activity testing or analysis of mutations in the lysosomal acid lipase gene (LIPA). The reference selection process was performed in two stages. The references were selected by two authors, and the data were extracted in June 2020. Summary of the findings: The initial search returned 1593 studies, and the final selection included 108 studies from 30 countries encompassing 206 patients, including individuals with Wolman disease and cholesteryl ester storage disease (CESD). The most prevalent manifestations in both spectra of the disease were hepatomegaly, splenomegaly, anemia, dyslipidemia, and elevated transaminases. Conclusions: Vomiting, diarrhea, jaundice, and splenomegaly may be correlated, and may serve as a starting point for investigating LAL-D. Familial lymphohistiocytosis should be part of the differential diagnosis with LAL-D, and all patients undergoing upper gastrointestinal endoscopy should be submitted to intestinal biopsy.

Lysosomal acid lipase deficiency in pediatric patients: a scoping review.

OBJECTIVE: Lysosomal acid lipase deficiency (LAL-D) is an underdiagnosed autosomal recessive disease with onset between the first years of life and adulthood. Early diagnosis is crucial for effective therapy and long-term survival. The objective of this article is to recognize warning signs among the clinical and laboratory characteristics of LAL-D in pediatric patients through a scope review. SOURCES: Electronic searches in the Embase, PubMed, Livivo, LILACS, Web of Science, Scopus, Google Scholar, Open Gray, and ProQuest Dissertations and Theses databases. The dataset included observational studies with clinical and laboratory characteristics of infants, children and adolescents diagnosed with lysosomal acid lipase deficiency by enzyme activity testing or analysis of mutations in the lysosomal acid lipase gene (LIPA). The reference selection process was performed in two stages. The references were selected by two authors, and the data were extracted in June 2020. SUMMARY OF THE FINDINGS: The initial search returned 1593 studies, and the final selection included 108 studies from 30 countries encompassing 206 patients, including individuals with Wolman disease and cholesteryl ester storage disease (CESD). The most prevalent manifestations in both spectra of the disease were hepatomegaly, splenomegaly, anemia, dyslipidemia, and elevated transaminases. CONCLUSIONS: Vomiting, diarrhea, jaundice, and splenomegaly may be correlated, and may serve as a starting point for investigating LAL-D. Familial lymphohistiocytosis should be part of the differential diagnosis with LAL-D, and all patients undergoing upper gastrointestinal endoscopy should be submitted to intestinal biopsy.

A Case of Lysosomal Acid Lipase Deficiency Confirmed by Response to Sebelipase Alfa Therapy.

Lysosomal acid lipase (LAL) deficiency, or cholesterol ester storage disease, is a disorder affecting the breakdown of cholesterol esters and triglycerides within lysosomes. Clinical findings include hepatomegaly, hepatic dysfunction, and dyslipidemia with a wide range of phenotypic variability and age of onset. The available clinical and molecular information of the patient presented herein was consistent with a diagnosis of LAL deficiency, but her LAL activity assay repeatedly showed normal or borderline low results. Her response to enzyme replacement therapy and demonstrable deficiency on a newer specific enzymatic assay ultimately confirmed her diagnosis of LAL deficiency.

A case of abdominal pain with dyslipidemia: difficulties diagnosing cholesterol ester storage disease.

Cholesterol ester storage disease is an exceptionally rare dyslipidemia with less than 150 cases reported in the medical literature. The diagnosis of Cholesterol Ester Storage Disease is often missed by virtue of the fact that the symptoms mimic both inborn metabolic defects and hepatic steatosis. Patients with Cholesterol Ester Storage Disease usually present with atypical complaints including abdominal pain from altered gut motility. Blood analysis typically reveals abnormal liver function tests with coincident dyslipidemia. We present a case of a young woman with Cholesterol Ester Storage Disease who was followed over two decades. We discuss issues common to her initial protracted diagnosis with management options over time.

[Lysosomal acid lipase deficiency in children: our experience and a novel possibility of enzyme replacement therapy]. / Manjak lizosomske kisele lipaze u djece: vlastita iskustva i nova mogucnost enzimskoga nadomjesnog lijecenja.

Lysosomal acid lipase deficiency is an autosomal recessive disorder with two distinct clinical phenotypes. Wolman disease is rapidly progressive with onset in early infancy. Complete enzyme deficiency results in massive accumulation of cholesterol esters and triglycerides in intestines, liver, spleen and other monocyte-macrophage system cells causing malabsorption, hepatosplenomegaly, liver failure and death in early infancy. Cholesterol ester storage disease may be diagnosed in childhood or later in life. It is characterized by chronic course and variable progression. Main features are variously expressed hepatopathy, including cirrhosis and liver failure, hypercholesterolemia and premature atherosclerosis. Characteristic is pathohistological finding of microvesicular steatosis and fibrosis and patognomonic are typical cholesterol ester crystals. Diagnosis is confirmed by enzyme assay and/or gene analysis. Until recently treatment was symptomatic. Ongoing clinical trials of enzyme replacement therapy have shown very promising results. We are presenting an infant with Wolman disease and two children with cholesterol ester storage disease with the aim to raise awareness about this disease and to start optimal care early.

Lysosomal acid lipase deficiency: diagnosis and treatment of Wolman and Cholesteryl Ester Storage Diseases.

Lysosomal acid lipase (LAL) is responsible for the hydrolysis of cholesterol esters and triglycerides. LAL is coded by the LIPA gene on chromosome 10q23.31. Its deficiency leads to two autosomal recessive disorders, Wolman disease (WD) and Cholesteryl Ester Storage Disease (CESD). WD has an estimated incidence of 1 in 500,000 live births and is the result of a complete loss of LAL and presents in infancy with vomiting, diarrhea, poor weight gain and hepatomegaly subsequently leading to death. CESD is the result of partial loss of LAL and its presentation is more variable. Patients may be asymptomatic or present with nonspecific gastrointestinal symptoms, hepatomegaly, elevated transaminases and dystipidemia which may be confused with the diagnosis of Non-alcoholic Fatty Liver Disease. CESD is currently underdiagnosed and has an estimated prevalence as high as I in 40,000 individuals. Radiologic findings in WD is calcification of the adrenal glands. Hepatomegaly is noted on CT scan in both WD and CESD. MRI may demonstrate accumulation of cholesterol esters and may be useful to study effects of potential medical therapies. The diagnosis of WD and CESD is based on LIPA gene sequencing and the measurement of LAL levels in peripheral blood leukocytes. Treatment of LAL deficiency is currently limited to control of cholesterol levels and to prevent premature atherosclerosis. Use of enzyme replacement therapy with recombinant human LAL in short-term studies has shown to be safe and effective.

Ezetimibe markedly attenuates hepatic cholesterol accumulation and improves liver function in the lysosomal acid lipase-deficient mouse, a model for cholesteryl ester storage disease.

Lysosomal acid lipase (LAL) plays a critical role in the intracellular handling of lipids by hydrolyzing cholesteryl esters (CE) and triacylglycerols (TAG) contained in newly internalized lipoproteins. In humans, mutations in the LAL gene result in cholesteryl ester storage disease (CESD), or in Wolman disease (WD) when the mutations cause complete loss of LAL activity. A rat model for WD and a mouse model for CESD have been described. In these studies we used LAL-deficient mice to investigate how modulating the amount of intestinally-derived cholesterol reaching the liver might impact its mass, cholesterol content, and function in this model. The main experiment tested if ezetimibe, a potent cholesterol absorption inhibitor, had any effect on CE accumulation in mice lacking LAL. In male Lal(-/-) mice given ezetimibe in their diet (20 mg/day/kg bw) for 4 weeks starting at 21 days of age, both liver mass and hepatic cholesterol concentration (mg/g) were reduced to the extent that whole-liver cholesterol content (mg/organ) in the treated mice (74.3±3.4) was only 56% of that in those not given ezetimibe (133.5±6.7). There was also a marked improvement in plasma alanine aminotransferase (ALT) activity. Thus, minimizing cholesterol absorption has a favorable impact on the liver in CESD.

Clinical effect and safety profile of recombinant human lysosomal acid lipase in patients with cholesteryl ester storage disease.

UNLABELLED: Cholesteryl ester storage disease (CESD), an inherited deficiency of lysosomal acid lipase (LAL), is an underappreciated cause of progressive liver disease with no approved therapy. Presenting features include dyslipidemia, elevated transaminases, and hepatomegaly. To assess the clinical effects and safety of the recombinant human LAL, sebelipase alfa, nine patients received four once-weekly infusions (0.35, 1, or 3 mg·kg(-1) ) in LAL-CL01, which is the first human study of this investigational agent. Patients completing LAL-CL01 were eligible to enroll in the extension study (LAL-CL04) in which they again received four once-weekly infusions of sebelipase alfa (0.35, 1, or 3 mg·kg(-1) ) before transitioning to long-term every-other-week infusions (1 or 3 mg·kg(-1) ). Sebelipase alfa was well tolerated, with mostly mild adverse events unrelated to sebelipase alfa. No antidrug antibodies were detected. Transaminases decreased in patients in LAL-CL01 and increased between studies. In seven patients receiving ongoing sebelipase alfa treatment in LAL-CL04, the mean ± standard deviation (SD) decreases for alanine transaminase and aspartate aminotransferase at week 12 compared to the baseline values in LAL-CL01 were 46 ± 21 U/L (-52%) and 21 ± 14 U/L (-36%), respectively (P ≤ 0.05). Through week 12 of LAL-CL04, these seven patients also showed mean decreases from baseline in total cholesterol of 44 ± 41 mg/dL (-22%; P = 0.047), low density lipoprotein-cholesterol of 29 ± 31 mg/dL (-27%; P = 0.078), and triglycerides of 50 ± 38 mg/dL (-28%, P = 0.016) and increases in high density lipoprotein-cholesterol of 5 mg/dL (15%; P = 0.016). CONCLUSION: These data establish that sebelipase alfa, an investigational enzyme replacement, in patients with CESD is well tolerated, rapidly decreases serum transaminases, and that these improvements are sustained with long-term dosing and are accompanied by improvements in serum lipid profile.

Cholesterol ester storage disease with unusual neurological manifestations in two siblings: a report from South India.

Cholesterol ester storage disease is a rare autosomal recessive storage disorder resulting from lysosomal acid lipase deficiency. Two siblings manifested with hepatosplenomegaly, ptosis, and bilateral external ophthalmoplegia. Evaluation revealed hyperlipidemia and bilateral adrenal calcifications. Leukocyte acid lipase levels were significantly low in both the patients, compared with controls, suggesting a diagnosis of cholesterol ester storage disease. Ptosis and external ophthalmoplegia have hitherto not been reported in cholesterol ester storage disease.

Cholesteryl ester storage disease in a young child presenting as isolated hepatomegaly treated with simvastatin.

Cholesteryl ester storage disease (CESD) is an autosomal recessive disorder resulting from lysosomal acid lipase deficiency and is usually characterized by hepatomegaly and hyperlipidemia. This paper reports a two-year-old boy who had hepatosplenomegaly, hyperlipidemia and hypertransaminasemia determined incidentally. The liver biopsy sample was orange-yellow in appearance. Microscopically, microvesicular steatosis and birefringent crystals were seen in liver biopsy. The diagnosis of CESD was confirmed by the reduced human acid lipase activity in peripheral leukocytes. Simvastatin therapy was given and tolerated without side effects. Our patient is the youngest reported case in the literature treated with 3-hydroxy 3-methyl glutaryl (HMG) CoA reductase inhibitor.

The role of mannosylated enzyme and the mannose receptor in enzyme replacement therapy.

Lysosomal acid lipase (LAL) is the critical enzyme for the hydrolysis of triglycerides (TGs) and cholesteryl esters (CEs) in lysosomes. LAL defects cause Wolman disease (WD) and CE storage disease (CESD). An LAL null (lal-/-) mouse model closely mimics human WD/CESD, with hepatocellular, Kupffer cell and other macrophage, and adrenal cortical storage of CEs and TGs. The effect on the cellular targeting of high-mannose and complex oligosaccharide-type oligosaccharide chains was tested with human LAL expressed in Pichia pastoris (phLAL) and CHO cells (chLAL), respectively. Only chLAL was internalized by cultured fibroblasts, whereas both chLAL and phLAL were taken up by macrophage mannose receptor (MMR)-positive J774E cells. After intraperitoneal injection into lal-/- mice, phLAL and chLAL distributed to macrophages and macrophage-derived cells of various organs. chLAL was also detected in hepatocytes. Ten injections of either enzyme over 30 d into 2- and 2.5-mo-old lal-/- mice produced normalization of hepatic color, decreased liver weight (50%-58%), and diminished hepatic cholesterol and TG storage. Lipid accumulations in macrophages were diminished with either enzyme. Only chLAL cleared lipids in hepatocytes. Mice double homozygous for the LAL and MMR deficiences (lal-/-;MMR-/-) showed phLAL uptake into Kupffer cells and hepatocytes, reversal of macrophage histopathology and lipid storage in all tissues, and clearance of hepatocytes. These results implicate MMR-independent and mannose 6-phosphate receptor-independent pathways in phLAL uptake and delivery to lysosomes in vivo. In addition, these studies show specific cellular targeting and physiologic effects of differentially oligosaccharide-modified human LALs mediated by MMR and that lysosomal targeting of mannose-terminated glycoproteins occurs and storage can be eliminated effectively without MMR.

Treatment of dyslipidemia with lovastatin and ezetimibe in an adolescent with cholesterol ester storage disease.

BACKGROUND: Cholesterol ester storage disease (CESD) is an autosomal recessive illness that results from mutations in the LIPA gene encoding lysosomal acid lipase. CESD patients present in childhood with hepatomegaly and dyslipidemia characterized by elevated total and low-density lipoprotein cholesterol (LDL-C), with elevated triglycerides and depressed high-density lipoprotein cholesterol (HDL-C). Usual treatment includes a low fat diet and a statin drug. RESULTS: In an 18-year old with CESD, we documented compound heterozygosity for two LIPA mutations: a novel frameshift nonsense mutation and a deletion of exon 8. The patient had been treated with escalating doses of lovastatin for approximately 80 months, with approximately 15% decline in mean LDL-C. The addition of ezetimibe 10 mg to lovastatin 40 mg resulted in an additional approximately 16% decline in mean LDL-C. CONCLUSION: These preliminary anecdotal findings in a CESD patient with novel LIPA mutations support the longer term safety of statins in an adolescent patient and provide new data about the potential efficacy and tolerability of ezetimibe in this patient group.

Enzyme therapy for lysosomal acid lipase deficiency in the mouse.

Lysosomal acid lipase (LAL) is the critical enzyme for the hydrolysis of the triglycerides (TG) and cholesteryl esters (CE) delivered to lysosomes. Its deficiency produces two human phenotypes, Wolman disease (WD) and cholesteryl ester storage disease (CESD). A targeted disruption of the LAL locus produced a null (lal( -/-)) mouse model that mimics human WD/CESD. The potential for enzyme therapy was tested using mannose terminated human LAL expressed in Pichia pastoris (phLAL), purified, and administered by tail vein injections to lal( -/-) mice. Mannose receptor (MR)-dependent uptake and lysosomal targeting of phLAL were evidenced ex vivo using competitive assays with MR-positive J774E cells, a murine monocyte/macrophage line, immunofluorescence and western blots. Following (bolus) IV injection, phLAL was detected in Kupffer cells, lung macrophages and intestinal macrophages in lal( -/-) mice. Two-month-old lal( -/-) mice received phLAL (1.5 U/dose) or saline injections once every 3 days for 30 days (10 doses). The treated lal( -/-) mice showed nearly complete resolution of hepatic yellow coloration; hepatic weight decreased by approximately 36% compared to PBS-treated lal( -/-) mice. Histologic analyses of numerous tissues from phLAL-treated mice showed reductions in macrophage lipid storage. TG and cholesterol levels decreased by approximately 50% in liver, 69% in spleen and 50% in small intestine. These studies provide feasibility for LAL enzyme therapy in human WD and CESD.

Long-term administration of the HMG-CoA reductase inhibitor lovastatin in two patients with cholesteryl ester storage disease.

OBJECTIVE: In order to suppress de novo cholesterol and VLDL biosynthesis, a long-term therapy trial with lovastatin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, was initiated in two patients with cholesteryl ester storage disease (CESD), and concentrations of plasma lipids were monitored over a period of 9 years. METHODS: We studied two male patients with enzymatically confirmed CESD in whom long-term lovastatin therapy (8 and 9 years) was begun at the age of 7 and 19 years. The diagnosis of CESD was confirmed by the measurement of human lysosomal acid lipase (hLAL) activity in cultured skin fibroblasts and leukocytes. Restriction fragment length polymorphism (RFLP) analysis revealed that both subjects are homozygotes for the common CESD splice site mutation. Levels of serum lipids and lipoproteins were measured yearly. RESULTS: During the first year, total serum cholesterol decreased from 317 to 201 mg/dl in Patient A and from 228 to 120 mg/dl in Patient B, due mainly to the reduction of low-density lipoprotein (LDL) cholesterol from 262 to 151 mg/dt in Patient A and from 166 to 66 mg/dl in Patient B. Accordingly, the LDL cholesterol : high density lipoprotein (HDL) cholesterol ratio was markedly reduced in both patients after one year of therapy. The treatment was continued and, after 9 years of further medication, low total cholesterol and LDL cholesterol levels were still maintained. CONCLUSIONS: The study demonstrates that HMG-CoA reductase inhibitors are well tolerated drugs during long-term treatment of CESD patients and may help to prevent the development of premature atherosclerosis.

A novel variant of lysosomal acid lipase in cholesteryl ester storage disease associated with mild phenotype and improvement on lovastatin.

Cholesterol ester storage disease (CESD) is a rare congenital disorder of lipid metabolism, with mutation of the lysosomal acid lipase gene, causing chronic liver disease, usually before adolescence. We here describe three adult siblings with CESD diagnosed by light microscopic demonstration of excessive lysosomal storage of lipids with accumulation of foamy cells in liver biopsies and by a decrease in acid lipase activity (2-3% of controls). One patient (male, 46a) had extensive liver fibrosis, another (female, 58a) had cirrhosis of the liver. The third patient had died from variceal haemorrhage (female, 56a). Using sequence analysis of RT-PCR products of LAL mRNA, the patients were identified as compound heterozygotes for a G-->A substitution at position -1 of the exon 8 splice donor site and a point mutation at the second allele, resulting in a His108-->Pro shift. In two patients, therapy with lovastatin was initiated, which led to normalisation of serum cholesterol and triglyceride levels. After 12 months, liver biopsy demonstrated a significant decrease in vacuolisation of hepatocytes, with fewer and smaller droplets. Semi-automated computer-assisted image analysis of electron microscopic sections demonstrated a decrease in the hepatocellular lysosomal area from 20.5+/-7.1% to 11.7+/-6.5% (p<0.05) and 41.7+/-5.1% to 33.4+/-4.4% (p<0.01). We conclude that in two siblings with a novel LAL variant and mild phenotype of CESD, lovastatin decreased both serum lipid concentrations and hepatocellular lysosomal content.