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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.

Lysosomal acid lipase (LAL), encoded by the lipase A ( LIPA) gene, hydrolyzes cholesteryl esters and triglycerides to generate free fatty acids and cholesterol in the cell. The essential role of LAL in lipid metabolism has been confirmed in mice and human with LAL deficiency. In humans, loss-of-function mutations of LIPA cause rare lysosomal disorders, Wolman disease and cholesteryl ester storage disease, in which LAL enzyme-replacement therapy has shown significant benefits in a phase 3 clinical trial. Recent studies have revealed the regulatory role of lipolytic products of lysosomal lipid hydrolysis in catabolic, anabolic, and signaling pathways. In vivo studies in mice with knockout of Lipa highlight the systemic impact of Lipa deficiency on metabolic homeostasis and immune cell function. Genome-wide association studies and functional genomic studies have identified LIPA as a risk locus for coronary heart disease, but the causal variants and mechanisms remain to be determined. Future studies will continue to focus on the role of LAL in the crosstalk between lipid metabolism and cellular function in health and diseases including coronary heart disease.

Wolman disease is an ultrarare lysosomal storage disease caused by a mutation in the LIPA gene. The clinical features of Wolman disease include early onset of vomiting, diarrhea, failure to thrive, hepatosplenomegaly, and bilateral adrenal calcification. We report the case of a 3-month-old infant who presented clinical features of hemophagocytic lymphohistiocytosis. Genetic sequence analysis of the LIPA gene revealed homozygous mutation c.153 C>A (p.Tyr51*). The parents were heterozygous for this mutation. Prenatal diagnosis has been carried out in the next pregnancy. To our knowledge, this mutation has never been reported before, and this is an unusual case of secondary hemophagocytic lymphohistiocytosis complicating Wolman disease.

Objectives: Evidence suggests that lysosomal acid lipase deficiency (LAL-D) is often underdiagnosed because symptoms may be nonspecific. We aimed to investigate the prevalence of LAL-D in children with unexplained liver disease and to identify demographic and clinical features with a prospective, multicenter, cross-sectional study., Methods: Patients (aged 3 months-18 years) who had unexplained transaminase elevation, unexplained hepatomegaly or hepatosplenomegaly, obesity-unrelated liver steatosis, biopsy-proven cryptogenic fibrosis and cirrhosis, or liver transplantation for cryptogenic cirrhosis were enrolled. A Web-based electronic data collection system was used. LAL activity (nmol/punch/h) was measured using the dried blood spot method and classified as LAL-D (<0.02), intermediate (0.02-0.37) or normal (> 0.37). A second dried blood spot sample was obtained from patients with intermediate LAL activity for confirmation of the result., Results: A total of 810 children (median age 5.6 years) from 795 families were enrolled. The reasons for enrollment were unexplained transaminase elevation (62%), unexplained organomegaly (45%), obesity-unrelated liver steatosis (26%), cryptogenic fibrosis and cirrhosis (6%), and liver transplantation for cryptogenic cirrhosis (<1%). LAL activity was normal in 634 (78%) and intermediate in 174 (21%) patients. LAL-D was identified in 2 siblings aged 15 and 6 years born to unrelated parents. Dyslipidemia, liver steatosis, and mild increase in aminotransferases were common features in these patients. Moreover, the 15-year-old patient showed growth failure and microvesicular steatosis, portal inflammation, and bridging fibrosis in the liver biopsy. Based on 795 families, 2 siblings in the same family were identified as LAL-D cases, making the prevalence of LAL-D in this study population, 0.1% (0.125%-0.606%). In the repeated measurement (76/174), LAL activity remained at the intermediate level in 38 patients., Conclusions: Overall, the frequency of LAL-D patients in this study (0.1%) suggests that LAL-D seems to be rare even in the selected high-risk population.

Background: Infant leukemia most commonly present with pallor and hepatosplenomegaly. The possibility of other differential diagnosis also has to be kept in mind during evaluation, as identifying the precise etiology for this clinical presentation is crucial for management., Observation: An infant, was referred to us with suspected infant leukemia and was subsequently diagnosed to have lysosomal acid lipase deficiency/Wolman disease with a novel 5 bp deletion "c.1180&#95;1184del" in the last exon (exon 10) of the lipase A (LIPA) gene., Conclusions: Hepatosplenomegaly and pallor resulting from nutritional deficiency or bone marrow involvement in Wolman disease can mimic infant leukemia.

Objective: LIPA gene mutations result in deficiency of lysosomal acid lipase and present phenotypically as Wolman disease or cholesteryl ester storage disease (CESD) depending on the level of deficiency. Patients with CESD may often be misdiagnosed because symptoms may be nonspecific. Symptoms may present in infancy if there is complete loss of lysosomal acid lipase or in early childhood or adulthood when there is partial loss. The purpose of the present study is to review the literature for pediatric cases of CESD to better understand the phenotype of CESD., Methods: A PubMed search of all English-language publications from 1966 through June 2012 for pediatric CESD case reports using the following key words CESD, fatty liver, and NAFLD was performed. All of the cases were reviewed and information regarding age, sex, presenting symptoms, and pertinent laboratory tests were recorded., Results: Seventy-one cases were culled from 39 published case reports. Nearly two-thirds of these patients presented with their first symptoms when they were younger than 5 years. Hepatomegaly and splenomegaly were common features. Serum transaminases and lipids were often elevated. Gastrointestinal symptoms were noted in approximately one-third of cases. Two-thirds of patients had liver fibrosis., Conclusions: CESD has an estimated incidence as high as 1 in 40,000, which means that it is presently underdiagnosed. Education about common symptoms of CESD as well as a higher level of suspicion for screening for CESD will lead to earlier diagnosis. New treatments for CESD including possible enzyme replacement therapy make early diagnosis especially important.