Lysosomal Acid Lipase Deficiency Research Articles

Current approaches to the diagnosis and treatment of lysosomal acid lipase deficiency

Lysosomal acid lipase deficiency is a chronic hereditary degenerative disease, substantially worsening quality of life and leading to lethal outcome. The condition is caused by a mutation of the LIPA gene, that is encoding lysosomal acid lipase, resulting in build-up of cholesterol esters and triglycerides. Clinical-pattern is quite variable: from rapidly worsening lethal infant form and severe infant cases with cirrhosis and liver dysfunction in adolescents to subclinical, mostly asymptomatic forms, manifesting in adults. Thus, major part of patients remains unexamined and the pathology itself undiagnosed, so the real incidence is unclear. This article describes clinical case of the diagnostics of lysosomal acid lipase deficiency in RNO-Alania. Efficiency and safety of enzyme substitution treatment is shown.

A SURVEY OF ACYLCARNITINE METHODS AND QUALITY CONTROL PROTOCOLS FROM CLINICAL LABORATORIES SUBMITTED ON BEHALF OF THE SIMD LABORATORY WORKGROUP

Lysosomal acid lipase deficiency (LAL-D) is a phenotypic continuum between the severe Wolman disease and the attenuated cholesteryl ester storage disease (CESD).To study if the amount of residual LAL enzymatic activity in dried blood spots (DBS) correlates with the LAL-D disease severity.DBS from Wolman and CESD patients, LAL-D carriers, and presumably unaffected random newborns were acquired. LAL enzymatic activity in DBS were measured using a novel, highly specific LAL substrate.Patients with Wolman disease displayed significantly lower LAL enzymatic activity compared to CESD patients. This was not observed with the traditional assay in which a non-specific substrate was used together with an LAL-specific inhibitor.The new LAL enzymatic activity assay using the specific substrate offers an improved biochemical genetics method for the diagnosis of LAL-D in symptomatic patients and more importantly, for the prognosis of asymptomatic patients who test positive in population-wide LAL-D newborn screening.

A Novel Variant in the LIPA Gene Associated with Distinct Phenotype.

Deficiency of lysosomal acid lipase (LAL-D) is caused by biallelic pathogenic variants in the LIPA gene. Spectrum of LAL-D ranges from early onset of hepatosplenomegaly and psychomotor regression (Wolman disease) to a more chronic course (cholesteryl ester storage disease - CESD). The diagnosis is based on lipid and biomarker profiles, specific liver histopathology, enzyme deficiency, and identification of causative genetic variants. Biomarker findings are a useful for diagnostics of LAL-D, including high plasma concentration of chitotriosidase as well as elevated oxysterols. Current treatment options include enzyme replacement therapy (sebelipase-alpha), statins, liver transplantation, and stem cell transplantation. We present two pairs of siblings from Serbia with a distinctive phenotype resembling LAL-D with a novel variant of unknown significance (VUS) detected in the LIPA gene and residual LAL activity. All patients presented with hepatosplenomegaly at early childhood. In siblings from family 1, compound heterozygosity for a pathogenic c.419G>A (p.Trp140Ter) variant and a novel VUS c.851C>T (p.Ser284Phe) was detected. Patients from family 2 were homozygous for c.851C>T VUS and both have typical histopathologic findings for LAL-D in the liver. Enzyme activity of LAL was tested in three patients and reported as sufficient, and therefore enzyme replacement therapy could not be approved. When confronted with a challenge of diagnosing an inherited metabolic disorder, several aspects are taken into consideration: clinical manifestations, specific biomarkers, enzyme assay results, and molecular genetic findings. This report brings cases to light which have a considerable discrepancy between those aspects, namely the preserved LAL enzyme activity in presence of clinical manifestations and rare variants in the LIPA gene.

LAL deficiency induced myeloid-derived suppressor cells as targets and biomarkers for lung cancer

BackgroundMyeloid-derived suppressor cells (MDSCs) are a heterogeneous population of cells in tumor microenvironment, which suppress antitumor immunity. Expansion of various MDSC subpopulations is closely associated with poor clinical outcomes in...

Twice weekly dosing with sebelipase alfa rescues severely ill infants with Wolman disease

Twice weekly dosing with sebelipase alfa rescues severely ill infants with Wolman disease

Inflammation in LAL deficiency is driven by substrate accumulation

Inflammation in LAL deficiency is driven by substrate accumulation

Wolman disease presenting with secondary hemophagocytic lymphohistiocytosis

Wolman disease presenting with secondary hemophagocytic lymphohistiocytosis

Deficiência de Lipase Ácida Lisossômica (LAL): Análise Enzimática em Papel-filtro como Ferramenta Diagnóstica em Paciente com Diagnóstico Prévio de Doença de Niemann-Pick tipo C

Lysosomal acid lipase deficiency (LAL-D) is a lysosomal storage disorder involved in cholesterol ester metabolism. It is a poorly understood genetic cause of cirrhosis, dyslipidemia and premature atherosclerotic disease in children and adults. As the manifestations of LAL-D may resemble those observed in other more common diseases, delayed diagnosis is not uncommon. Wolman disease is an early-onset LAL-D phenotype that is usually fatal in the first year of life, but the most common form of the disease may occur at all ages. Recently, enzyme replacement therapy (ERT) for LAL-D has become available. Case report: A 12- year-old male patient was referred for hepatomegaly. Initially diagnosed as having Niemann-Pick type C disease (NPC), it did not present confirmatory mutations of this disease. Later, with enzymatic dosage of lysosomal acid lipase on filter paper, the diagnosis was redirected to LAL-D (with confirmation in enzymatic dosage in leukocytes and fibroblasts). Discussion: Although LAL-D is considered a rare and uncommon cause of liver disease, recent studies point to a higher prevalence of this disease. Early diagnosis is essential, since specific treatment for this disease is already available. About half of patients with LAL-D die before age 21 in the absence of adequate treatment

Deficiência de Lipase Ácida Lisossômica (LAL): análise enzimática em papel-filtro como ferramenta diagnóstica em paciente com diagnóstico prévio de doença de Niemann-Pick tipo C

INTRODUCTION: Lysosomal acid lipase deficiency (LAL-D) is a lysosomal storage disorder involved in cholesterol ester metabolism. It is a poorly understood genetic cause of cirrhosis, dyslipidemia and premature atherosclerotic disease in children and adults. As the manifestations of LAL-D may resemble those observed in other more common diseases, delayed diagnosis is not uncommon. Wolman disease is an early-onset LAL-D phenotype that is usually fatal in the first year of life, but the most common form of the disease may occur at all ages. Recently, enzyme replacement therapy (ERT) for LAL-D has become available. CASE REPORT: A 12-year-old male patient was referred for hepatomegaly. Initially diagnosed as having Niemann-Pick type C disease (NPC), it did not present confirmatory mutations of this disease. Later, with enzymatic dosage of lysosomal acid lipase on filter paper, the diagnosis was redirected to LAL-D (with confirmation in enzymatic dosage in leukocytes and fibroblasts). DISCUSSION: Although LAL-D is considered a rare and uncommon cause of liver disease, recent studies point to a higher prevalence of this disease. Early diagnosis is essential, since specific treatment for this disease is already available. About half of patients with LAL-D die before age 21 in the absence of adequate treatment.

Rare diseases presenting with hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is a potentially fatal hyperinflammatory disorder characterized by hypercytokinemia caused by excessive activation of cytotoxic T cells and macrophages. HLH is caused by a variety of factors and is classified into primary and secondary HLH. Familial HLH (FHL) types 1-5, X-linked lymphoproliferative syndrome types 1 and 2, and FHL syndrome with hypopigmentation are all examples of primary HLH. Secondary HLH, on the other hand, is linked to infections, malignant tumors, autoimmune diseases, and other diseases. The causes of HLH vary, and finding the underlying disease is critical for diagnosis and treatment. The majority of HLH is caused by the aforementioned conditions; however, approximately 10% of cases are caused by rare diseases such as inborn errors of immunity (IEI) and inborn errors of metabolism (IEM). Novel IEI, such as RhoG, MAP kinase activating death domain, TIM3, and ZNFX1 deficiencies, have recently been identified as causes of HLH. IEM patients are rarely associated with HLH. Surprisingly, children with lysinuric protein intolerance and lysosomal acid lipase deficiency (Wolman disease) frequently develop HLH. This review focuses on the most recent knowledge of HLH caused by rare diseases such as IEI and IEM.

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 storage diseases. Sphingolipidoses — sphingomyelin lipidosis, or Niemann–Pick disease, Wolman disease

The epidemiology, clinical biochemical and molecular genetic characteristics of glycosphingolipidoses with impaired metabolism and excessive accumulation in parenchymal organs, bone and brain not only of sphingolipids, but also free cholesterol are presented. First of all, it is sphingomyelin lipidosis, or NiemannPick disease, a clinically polymorphic and genetically heterogeneous group of rare monogenic diseases. Types A and B, which differ in onset and severity, are allelic diseases and are caused by the presence of recessive mutations in the lysosomal acid sphingomyelinase (SMPD1) gene. Type A is a classic acute neuronopathy, which starts in 85% of cases before 6 months, death occurs before the age of 3 years. The cause of the disease is mutations with premature termination of translation or severe impairment of the catalytic activity of the enzyme. In type B, missense mutations are more common. This is a chronic visceral form, in which neurological symptoms are usually absent, and patients survive into adolescence. Juvenile and adult forms of chronic neuronopathy type C are genetically heterogeneous. In 95% of cases they are caused by mutations in the NPC1 gene (type C1) and in 5% in the NPC2 gene (type C2). The products of these genes are transmembrane proteins responsible for the transport of cholesterol and other lipids. Cholesterol ester storage disease, or Wolman disease, is caused by hereditary deficiency of lysosomal acid lipase A. The possibility of early diagnosis of these diseases based on neonatal screening is discussed in order to increase the effectiveness of their prevention and treatment. The importance of experimental models for studying the molecular basis of the pathogenesis of these severe hereditary diseases and developing various therapeutic approaches, such as bone marrow transplantation, enzyme replacement therapy, and substrate-reducing therapy, is emphasized. A clinical example of NiemannPick disease type C is presented.

Stratification of patients with lysosomal acid lipase deficiency by enzyme activity in dried blood spots

BackgroundLysosomal acid lipase deficiency (LAL-D) is a phenotypic continuum between the severe Wolman disease and the attenuated cholesteryl ester storage disease (CESD). ObjectiveTo study if the amount of residual LAL enzymatic activity in dried blood spots (DBS) correlates with the LAL-D disease severity. MethodsDBS from Wolman and CESD patients, LAL-D carriers, and presumably unaffected random newborns were acquired. LAL enzymatic activity in DBS were measured using a novel, highly specific LAL substrate. ResultsPatients with Wolman disease displayed significantly lower LAL enzymatic activity compared to CESD patients. This was not observed with the traditional assay in which a non-specific substrate was used together with an LAL-specific inhibitor. ConclusionThe new LAL enzymatic activity assay using the specific substrate offers an improved biochemical genetics method for the diagnosis of LAL-D in symptomatic patients and more importantly, for the prognosis of asymptomatic patients who test positive in population-wide LAL-D newborn screening.

Natural history and management of liver dysfunction in lysosomal storage disorders.

Lysosomal storage disorders (LSD) are a rare group of genetic disorders. The major LSDs that cause liver dysfunction are disorders of sphingolipid lipid storage [Gaucher disease (GD) and Niemann-Pick disease] and lysosomal acid lipase deficiency [cholesteryl ester storage disease and Wolman disease (WD)]. These diseases can cause significant liver problems ranging from asymptomatic hepatomegaly to cirrhosis and portal hypertension. Abnormal storage cells initiate hepatic fibrosis in sphingolipid disorders. Dyslipidemia causes micronodular cirrhosis in lipid storage disorders. These disorders must be keenly differentiated from other chronic liver diseases and non-alcoholic steatohepatitis that affect children and young adults. GD, Niemann-Pick type C, and WD also cause neonatal cholestasis and infantile liver failure. Genotype and liver phenotype correlation is variable in these conditions. Patients with LSD may survive up to 4-5 decades except for those with neonatal onset disease. The diagnosis of all LSD is based on enzymatic activity, tissue histology, and genetic testing. Enzyme replacement is possible in GD and Niemann-Pick types A and B though there are major limitations in the outcome. Those that progress invariably require liver transplantation with variable outcomes. The prognosis of Niemann-Pick type C and WD is universally poor. Enzyme replacement therapy has a promising role in cholesteryl ester storage disease. This review attempts to outline the natural history of these disorders from a hepatologist's perspective to increase awareness and facilitate better management of these rare disorders.

Dysregulation of Placental Lipid Hydrolysis by High-Fat/High-Cholesterol Feeding and Gestational Diabetes Mellitus in Mice.

Advanced maternal age and obesity are the main risk factors to develop gestational diabetes mellitus (GDM). Obesity is a consequence of the increased storage of triacylglycerol (TG). Cytosolic and lysosomal lipid hydrolases break down TG and cholesteryl esters (CE) to release fatty acids (FA), free cholesterol, and glycerol. We have recently shown that intracellular lipases are present and active in the mouse placenta and that deficiency of lysosomal acid lipase alters placental and fetal lipid homeostasis. To date, intracellular lipid hydrolysis in GDM has been poorly studied despite the important role of FA in this condition. Therefore, we hypothesized that intracellular lipases are dysregulated in pregnancies complicated by maternal high-fat/high-cholesterol (HF/HCD) feeding with and without GDM. Placentae of HF/HCD-fed mice with and without GDM were more efficient, indicating increased nutrient transfer to the fetus. The increased activity of placental CE but not TG hydrolases in placentae of dams fed HF/HCD with or without GDM resulted in upregulated cholesterol export to the fetus and placental TG accumulation. Our results indicate that HF/HCD-induced dysregulation of placental lipid hydrolysis contributes to fetal hepatic lipid accumulation and possibly to fetal overgrowth, at least in mice.

Lysosomal acid lipase deficiency: A rare inherited dyslipidemia but potential ubiquitous factor in the development of atherosclerosis and fatty liver disease.

Lysosomal acid lipase (LAL), encoded by the gene LIPA, is the sole neutral lipid hydrolase in lysosomes, responsible for cleavage of cholesteryl esters and triglycerides into their component parts. Inherited forms of complete (Wolman Disease, WD) or partial LAL deficiency (cholesteryl ester storage disease, CESD) are fortunately rare. Recently, LAL has been identified as a cardiovascular risk gene in genome-wide association studies, though the directionality of risk conferred remains controversial. It has also been proposed that the low expression and activity of LAL in arterial smooth muscle cells (SMCs) that occurs inherently in nature is a likely determinant of the propensity of SMCs to form the majority of foam cells in atherosclerotic plaque. LAL also likely plays a potential role in fatty liver disease. This review highlights the nature of LAL gene mutations in WD and CESD, the association of LAL with prediction of cardiovascular risk from genome-wide association studies, the importance of relative LAL deficiency in SMC foam cells, and the need to further interrogate the pathophysiological impact and cell type-specific role of enhancing LAL activity as a novel treatment strategy to reduce the development and induce the regression of ischemic cardiovascular disease and fatty liver.

LC-MS/MS-based enzyme assay for lysosomal acid lipase using dried blood spots

Lysosomal acid lipase deficiency (LAL-D) (OMIM: 278000) is a lysosomal storage disorder with two distinct disease phenotypes such as Wolman disease and cholesteryl ester storage disorder (CESD), characterized by an accumulation of endocytosed cholesterol in the body. Due to the presence of multiple lipases in DBS, previous studies measured LAL enzyme activity in the presence of Lalistat-2, an established LAL-specific inhibitor (Hamilton J et al Chim Clin Acta (2012) 413:1207–1210). Alternatively, a novel substrate specific for LAL has been reported very recently (Masi S. et al Clin Chem (2018) 64:690–696). In this study, we examined the LAL enzyme activity of a Japanese population with the LAL-specific substrate using liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based enzyme assay whether an affected individual can be identified among this population. To achieve this, we first performed assay validation using LC-MS/MS. Under our experimental setting, typically we obtained LAL enzyme activity for QC High (100% enzyme activity) as 261.9 ± 3.2 μmol/h/L (n = 5) and for QC Low as (5% enzyme activity) as 14.7 ± 0.5 μmol/h/L (n = 5). The percentage of coefficient of variation for interday assay for QC High was 9.6% (n = 4) and for QC Low was 7.9% (n = 4), respectively. Based on these results, we further examined the LAL enzyme activity of control Japanese population and that of affected individuals with Wolman disease and CESD. The averaged enzyme activity for control newborns, Wolman, and CESD was 123.9 ± 53.9 μmol/h/L (n = 131), 6.6 ± 0.9 μmol/h/L (n = 3), and 4.8 ± 0.3 μmol/h/L (n = 3), respectively. These results suggest that an LAL-D-affected individual can be readily identified by enzyme activity using LC-MS/MS-based technique.

Therapeutic efficacy of rscAAVrh74.miniCMV.LIPA gene therapy in a mouse model of lysosomal acid lipase deficiency

Lysosomal acid lipase deficiency (LAL-D) presents as one of two rare autosomal recessive diseases: Wolman disease (WD), a severe disorder presenting in infancy characterized by absent or very low LAL activity, and cholesteryl ester storage disease (CESD), a less severe, later onset disease form. Recent clinical studies have shown efficacy of enzyme replacement therapy for both forms of LAL-D; however, no gene therapy approach has yet been developed for clinical use. Here, we show that rscAAVrh74.miniCMV.LIPA gene therapy can significantly improve disease symptoms in the Lipa−/− mouse model of LAL-D. Treatment dramatically lowered hepatosplenomegaly, liver and spleen triglyceride and cholesterol levels, and serum expression of markers of liver damage. Measures of liver inflammation and fibrosis were also reduced. Treatment of young adult mice was more effective than treatment of neonates, and enzyme activity was elevated in serum, consistent with possible bystander effects. These results demonstrate that adeno associated virus (AAV)-mediated LIPA gene-replacement therapy may be a viable option to treat patients with LAL-D, particularly patients with CESD.

Uncommon presentation of Cholesteryl Ester Storage Disease (CESD): Description of a case and genetic characterization by next generation sequencing

Background and Aims : The LIPA gene encodes the lysosomal acidic lipase (LAL), an enzyme which hydrolyzes cholesterol esters (CE) and triglycerides (TG). Cholesteryl Ester Storage Disease (CESD) is a rare recessive disease caused by mutations in LIPA gene which result in residual LAL activity. Complete LAL deficiency is associated with a more severe form of disease known as Wolman’s disease. Hyperlipidemia and liver steatosis are common clinical features of CESD.

Lysosomal acid lipase (LAL) deficiency alters immune cells distribution in mice and humans

Background and Aims : Lysosomal acid lipase (LAL) hydrolyses cholesterol esters and triglycerides within the lysosome, releasing free cholesterol and free fatty acids into the cytoplasm. According to the severity of genetic mutations, LAL deficiency presents in two hereditary and rare disorders: Wolman Disease (WD), with a severe phenotype and prognosis, and Cholesteryl Ester Storage Disease (CESD) with milder ones. As WD has been also associated with the occurrence of an abnormal proliferation and activation of hematopoietic cells, we aimed to investigate whether LAL has a direct effect on immune cells phenotype.