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Yan S, Fu F, Zhou H, Huang R, Wang Y, Liao C. Functional analysis of a novel splice site variant in the ASAH1 gene. Mol Genet Genomic Med 2024; 12:e2317. [PMID: 37962265 PMCID: PMC10767590 DOI: 10.1002/mgg3.2317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 10/11/2023] [Accepted: 10/22/2023] [Indexed: 11/15/2023] Open
Abstract
BACKGROUND Acid ceramidase (ACDase) deficiency is an ultrarare autosomal recessive lysosomal disorder caused by pathogenic N-acylsphingosine amidohydrolase (ASAH1) variants. It presents with either Farber disease (FD) or spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME). OBJECTIVE The study aims to identify a novel splice site variant in a hydrops fetus that causes ASAH1-related disorder, aid genetic counseling, and accurate prenatal diagnosis. METHODS We report a case of hydrops fetalis with a novel homozygous mutation in ASAH1 inherited from non-consanguineous parents. We performed copy number variation sequencing (CNV-Seq) and whole exome sequencing (WES) on the fetus and family, respectively. Minigene splicing analyses were conducted to confirm the pathogenic variants. RESULTS WES data revealed a splice site variant of the ASAH1 (c.458-2A>T), which was predicted to affect RNA splicing. Minigene splicing analyses found that the c.458-2A>T variant abolished the canonical splicing of intron 6, thereby activating two cryptic splicing products (c.456_458ins56bp and c.458_503del). CONCLUSIONS Overall, we identified a novel splice site variant in the mutational spectrum of ASAH1 and its aberrant effect on splicing. These findings highlight the importance of ultrasonic manifestation and family history of fetal hydrops during ASAH1-related disorders and could also aid genetic counseling and accurate prenatal diagnosis. To the best of our knowledge, this is the shortest-lived account of ASAH1-related disorders in utero with severe hydrops fetalis.
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Affiliation(s)
- Shujuan Yan
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical CenterGuangzhou Medical UniversityGuangzhouGuangdongChina
| | - Fang Fu
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical CenterGuangzhou Medical UniversityGuangzhouGuangdongChina
| | - Hang Zhou
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical CenterGuangzhou Medical UniversityGuangzhouGuangdongChina
| | - Ruibin Huang
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical CenterGuangzhou Medical UniversityGuangzhouGuangdongChina
| | - You Wang
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical CenterGuangzhou Medical UniversityGuangzhouGuangdongChina
| | - Can Liao
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical CenterGuangzhou Medical UniversityGuangzhouGuangdongChina
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Kleynerman A, Rybova J, Faber ML, McKillop WM, Levade T, Medin JA. Acid Ceramidase Deficiency: Bridging Gaps between Clinical Presentation, Mouse Models, and Future Therapeutic Interventions. Biomolecules 2023; 13:biom13020274. [PMID: 36830643 PMCID: PMC9953133 DOI: 10.3390/biom13020274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023] Open
Abstract
Farber disease (FD) and spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME) are ultra-rare, autosomal-recessive, acid ceramidase (ACDase) deficiency disorders caused by ASAH1 gene mutations. Currently, 73 different mutations in the ASAH1 gene have been described in humans. These mutations lead to reduced ACDase activity and ceramide (Cer) accumulation in many tissues. Presenting as divergent clinical phenotypes, the symptoms of FD vary depending on central nervous system (CNS) involvement and severity. Classic signs of FD include, but are not limited to, a hoarse voice, distended joints, and lipogranulomas found subcutaneously and in other tissues. Patients with SMA-PME lack the most prominent clinical signs seen in FD. Instead, they demonstrate muscle weakness, tremors, and myoclonic epilepsy. Several ACDase-deficient mouse models have been developed to help elucidate the complex consequences of Cer accumulation. In this review, we compare clinical reports on FD patients and experimental descriptions of ACDase-deficient mouse models. We also discuss clinical presentations, potential therapeutic strategies, and future directions for the study of FD and SMA-PME.
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Affiliation(s)
- Annie Kleynerman
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Jitka Rybova
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Mary L. Faber
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - William M. McKillop
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Thierry Levade
- Laboratoire de Biochimie Métabolique, CHU Toulouse, and INSERM U1037, Centre de Recherches en Cancérologie de Toulouse, Université Paul Sabatier, 31062 Toulouse, France
| | - Jeffrey A. Medin
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Correspondence: ; Tel.: +1-414-955-4118
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Abstract
Acid ceramidase (ACDase) deficiency is a spectrum of disorders that includes a rare lysosomal storage disorder called Farber disease (FD) and a rare epileptic disorder called spinal muscular atrophy with progressive myoclonic epilepsy (SMA-PME). Both disorders are caused by mutations in the ASAH1 gene that encodes the lysosomal hydrolase that breaks down the bioactive lipid ceramide. To date, there have been fewer than 200 reported cases of FD and SMA-PME in the literature. Typical textbook manifestations of classical FD include the formation of subcutaneous nodules, accumulation of joint contractures, and development of a hoarse voice. In reality, however, the clinical presentation is much broader. Patients may develop severe pathologies leading to death in infancy or may develop attenuated forms of the disorder wherein they are often misdiagnosed or not diagnosed until adulthood. A clinical variability also exists for SMA-PME, in which patients develop progressive muscle weakness and seizures. Currently, there is no known cure for FD or for SMA-PME. The main treatment is symptom management. In rare cases, treatment may include surgery or hematopoietic stem cell transplantation. Research using disease models has provided insights into the pathology as well as the role of ACDase in the development of these conditions. Recent studies have highlighted possible biomarkers for an effective diagnosis of ACDase deficiency. Ongoing work is being conducted to evaluate the use of recombinant human ACDase (rhACDase) for the treatment of FD. Finally, gene therapy strategies for the treatment of ACDase deficiency are actively being pursued. This review highlights the broad clinical definition and outlines key studies that have improved our understanding of inherited ACDase deficiency-related conditions.
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Affiliation(s)
- Fabian P S Yu
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Samuel Amintas
- Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France
| | - Thierry Levade
- Laboratoire de Biochimie Métabolique, Institut Fédératif de Biologie, CHU Purpan, Toulouse, France. .,INSERM UMR1037 CRCT, Université de Toulouse, Toulouse, France.
| | - Jeffrey A Medin
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada. .,Departments of Pediatrics and Biochemistry, Medical College of Wisconsin, Milwaukee, WI, USA.
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Dworski S, Berger A, Furlonger C, Moreau JM, Yoshimitsu M, Trentadue J, Au BCY, Paige CJ, Medin JA. Markedly perturbed hematopoiesis in acid ceramidase deficient mice. Haematologica 2015; 100:e162-5. [PMID: 25682603 DOI: 10.3324/haematol.2014.108530] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Affiliation(s)
| | | | | | | | - Makoto Yoshimitsu
- Division of Hematology and Immunology, Center for Chronic Viral Diseases, Graduate School of Medical and Dental Sciences, Kagoshima University, Japan
| | | | | | - Christopher J Paige
- University Health Network, Toronto, Canada Department of Immunology, University of Toronto, Canada Department of Medical Biophysics, University of Toronto, Canada
| | - Jeffrey A Medin
- Institute of Medical Science, University of Toronto, Canada University Health Network, Toronto, Canada Department of Medical Biophysics, University of Toronto, Canada
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Jones EE, Dworski S, Canals D, Casas J, Fabrias G, Schoenling D, Levade T, Denlinger C, Hannun YA, Medin JA, Drake RR. On-tissue localization of ceramides and other sphingolipids by MALDI mass spectrometry imaging. Anal Chem 2014; 86:8303-11. [PMID: 25072097 PMCID: PMC4139181 DOI: 10.1021/ac501937d] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
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A novel MALDI-FTICR imaging mass
spectrometry (MALDI-IMS) workflow
is described for on-tissue detection, spatial localization, and structural
confirmation of low abundance bioactive ceramides and other sphingolipids.
Increasingly, altered or elevated levels of sphingolipids, sphingolipid
metabolites, and sphingolipid metabolizing enzymes have been associated
with a variety of disorders such as diabetes, obesity, lysosomal storage
disorders, and cancer. Ceramide, which serves as a metabolic hub in
sphingolipid metabolism, has been linked to cancer signaling pathways
and to metabolic regulation with involvement in autophagy, cell-cycle
arrest, senescence, and apoptosis. Using kidney tissues from a new
Farber disease mouse model in which ceramides of all acyl chain lengths
and other sphingolipid metabolites accumulate in tissues, specific
ceramides and sphingomyelins were identified by on-tissue isolation
and fragmentation, coupled with an on-tissue digestion by ceramidase
or sphingomyelinase. Multiple glycosphingolipid species were also
detected. The newly generated library of sphingolipid ions was then
applied to MALDI-IMS of human lung cancer tissues. Multiple tumor
specific ceramide and sphingomyelin species were detected and confirmed
by on-tissue enzyme digests and structural confirmation. High-resolution
MALDI-IMS in combination with novel on-tissue ceramidase and sphingomyelinase
enzyme digestions makes it now possible to rapidly visualize the distribution
of bioactive ceramides and sphingomyelin in tissues.
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Affiliation(s)
- E Ellen Jones
- Department of Cell and Molecular Pharmacology and MUSC Proteomics Center, Medical University of South Carolina , 173 Ashley Avenue, Charleston, South Carolina 29425, United States
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Singh AT, Dharmarajan A, Aye ILMH, Keelan JA. Ceramide biosynthesis and metabolism in trophoblast syncytialization. Mol Cell Endocrinol 2012; 362:48-59. [PMID: 22652149 DOI: 10.1016/j.mce.2012.05.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Revised: 05/02/2012] [Accepted: 05/18/2012] [Indexed: 02/02/2023]
Abstract
Sphingolipid mediators such as ceramide are pleiotropic regulators of cellular growth, differentiation and apoptosis. We investigated the role of ceramide biosynthesis, metabolism and actions in term human cytotrophoblasts syncytialized over 7 days in culture. Intracellular C16 ceramide levels increased modestly after 3 days in culture, then declined. Ceramidase was present at particularly high levels in syncytialized trophoblasts; inhibition of ceramidase reduced the degree of cell fusion. Exposure to short chain C8 ceramide or aSMase enhanced secretion of the differentiation marker hCG without affecting fusion or cell viability. In contrast, pharmacological inhibition of ceramidase reduced the extent of fusion. Inhibition of the ceramide-responsive JNK and PP2A pathways did not abolish the effects of ceramide, and JNK phosphorylation was unresponsive to ceramide; however, ceramide significantly inhibited phosphorylation of Akt. This study suggests that changes in ceramide biosynthesis and metabolism play a differential role in the biochemical and morphological features of trophoblast differentiation.
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Affiliation(s)
- Ambika T Singh
- School of Women's and Infant's Health, Dentistry and Health Sciences, The University of Western Australia, Perth, Australia
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Eliyahu E, Shtraizent N, He X, Chen D, Shalgi R, Schuchman EH. Identification of cystatin SA as a novel inhibitor of acid ceramidase. J Biol Chem 2011; 286:35624-35633. [PMID: 21846728 DOI: 10.1074/jbc.m111.260372] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Autoproteolytic cleavage of the inactive acid ceramidase (AC) precursor into the active heterodimer exposes a free cysteine residue, leading us to study whether AC could be regulated by one or more members of the cystatin family. Co-expression of the full-length AC and cystatin SA (cysSA) cDNAs led to significant reduction of AC activity in the transfected cells. Expression of cysSA also inhibited endogenous AC activity in cells and increased ceramide. Conversely, cysSA siRNA expression led to elevated AC activity and reduction in ceramide. The effects of cysSA siRNA expression could be reversed by the addition of recombinant cysSA into the culture media. These results were consistent with detection of a physical interaction between AC and cysSA, assessed by co-immunoprecipitation and nickel-nitrilotriacetic acid affinity chromatography, and further supported by co-localization of the endogenous proteins using confocal microscopy. In vitro kinetic analysis of purified, recombinant AC and cysSA confirmed the transfection results and suggested a non-competitive type of inhibition with a K(i) in the low micromolar range. Processing of the AC precursor into the active form was not affected by cysSA expression, suggesting that it likely inhibits AC by allosteric interference. Computer modeling and expression studies identified several potential inhibitory domains in cysSA, including a small "AC-like" domain (identical to the AC cleavage site, TICT). Small peptides, synthesized with combinations of this and a "cystatin-like" domain (QXVXG), exhibited significant AC inhibition as well. Such peptide-based AC inhibitors could potentially be used to regulate AC activity in cancer cells that are known to overexpress this enzyme alone and in combination with conventional anti-cancer drugs.
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Affiliation(s)
- Efrat Eliyahu
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | - Nataly Shtraizent
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029; Department of Developmental and Cell Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel 69978
| | - Xingxuan He
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | - Dafna Chen
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029
| | - Ruth Shalgi
- Department of Developmental and Cell Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel 69978
| | - Edward H Schuchman
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York 10029.
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Abstract
Hepatic dysfunction during childhood can be due to acquired or inherited etiologies or a combination. The distinction can be difficult to make on liver biopsy, because the inherited disorders are rare and often lack pathognomonic light microscopic features. Recent progress in understanding the pathogenesis of these disorders has led to advances in molecular genetic screening and confirmatory tests. For a majority of these disorders, the liver biopsy continues to play a crucial role in primary diagnosis or confirmation. This article discusses algorithms that may aid pathologists in differential diagnosis of common inherited disorders of the liver, with emphasis on ancillary diagnostic tools and reference assays that are critical in establishing the diagnosis.
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Affiliation(s)
- Angshumoy Roy
- Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Milton J Finegold
- Department of Pathology, Texas Children's Hospital, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.
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Abstract
BACKGROUND Lung involvement in children with Niemann-Pick disease has rarely been studied systematically. OBJECTIVE To assess the involvement of the lung and the value of bronchoalveolar lavage in children with Niemann-Pick diseases. DESIGN Retrospective analysis of patient records. PATIENTS Thirteen patients, with type A (n = 1), type B (n = 10), and type C (n = 2) Niemann-Pick disease, aged 2 months to 9 years at diagnosis, were included in the study. INTERVENTIONS Lung involvement was assessed by clinical evaluation, chest radiograph, lung computed tomography (CT) scan, pulmonary function tests, and bronchoalveolar lavage fluid analysis. RESULTS Respiratory symptoms were present at diagnosis in 10 patients and developed during follow up in the three other patients. All patients showed signs of interstitial lung disease on chest X-ray and lung CT scan. Bronchoalveolar lavage fluid analysis (n = 7) revealed a marked accumulation of foamy macrophages (Niemann-Pick cells) in all patients. At follow up, one patient died of respiratory failure, five patients required long term oxygen therapy and seven other patients presented a chronic obstructive pulmonary disease (n = 6) or chronic cough (n = 1). CONCLUSION Lung disease was observed in all the patients included in the present study. Bronchoalveolar lavage may be useful in Niemann-Pick diseases by showing the presence of characteristic Niemann-Pick cells.
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Affiliation(s)
- Nathalie Guillemot
- AP-HP, Hopital Armand Trousseau, Pediatric Pulmonary Department, Paris, France
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Abstract
Recent studies suggest that the lipid, ceramide, induces the default apoptosis process in eggs. Yet, it is obscure how newly formed embryos overcome this fate. Acid ceramidase (AC) is a key regulatory enzyme involved in ceramide metabolism, and mutations in the AC gene (Asah1) result in Farber Lipogranulomatosis, a fatal human genetic disorder. Our previous studies revealed that AC knockout (Asah1-/-) mice had a lethal phenotype, and herein we reveal the mechanism underlying this observation. A single-cell, polymerase chain reaction (PCR) genotyping method was developed to analyze individual embryos from Asah1 +/- intercrosses. Combined with Annexin V staining, this genotype analysis demonstrated that Asah1-/- embryos could not survive beyond the 2-cell stage, and underwent apoptotic death. Notably, sphingosine-1-phosphate (S1P) treatment of early 2-cell embryos from the Asah1 +/- intercrosses rescued Asah1-/- embryos, and enabled their progression from the 2-cell to 4-8-cell stage. Quantitative PCR also revealed that expression of the Asah1 gene in healthy embryos was initiated at the 2-cell stage, coincident with embryonic genome activation (EGA). AC activity and Western blot analyses further demonstrated high expression and activity of the enzyme in normal, unfertilized eggs, which likely provide the protein to newly formed embryos prior to EGA. Based on these observations, we suggest that AC is an essential factor required for embryo survival that functions by removing ceramide from the newly formed embryos, thus inhibiting the default apoptosis pathway.
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Affiliation(s)
- Efrat Eliyahu
- Department of Human Genetics, Mt. Sinai School of Medicine, 1425 Madison Avenue, New York, NY 10029, USA
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Li CM, Park JH, Simonaro CM, He X, Gordon RE, Friedman AH, Ehleiter D, Paris F, Manova K, Hepbildikler S, Fuks Z, Sandhoff K, Kolesnick R, Schuchman EH, Hepbiloikler S. Insertional mutagenesis of the mouse acid ceramidase gene leads to early embryonic lethality in homozygotes and progressive lipid storage disease in heterozygotes. Genomics 2002; 79:218-24. [PMID: 11829492 DOI: 10.1006/geno.2002.6686] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ceramide is an important cellular lipid involved in signal transduction and the biosynthesis of complex sphingolipids. It can be hydrolyzed into sphingosine, another important signaling lipid, by the activity of ceramidases. Point mutations in the gene (Asah1) encoding one ceramidase, acid ceramidase (AC), lead to the lysosomal storage disorder Farber disease (FD). To investigate the role of AC in mammalian development, we disrupted the mouse gene Asah1 in embryonic stem cells by homologous recombination mediated insertion of an AC targeting vector into the wild-type sequence. Genotype analysis of over 150 offspring or embryos from heterozygous intercrosses revealed an absence of Asah1(-/-) individuals at embryonic day (E) 8.5 or later, although the ratio of wild-type to Asah1(+/-) individuals from these intercrosses was 1:2. Northern blot analysis showed that AC expression was turned on early in development, by E7.0, and continued through at least E17. In contrast, expression of the related lipid hydrolase, acid sphingomyelinase, was shut down by E11. Asah1(+/-) mice survived and lived a normal lifespan, but developed a progressive lipid storage disease in several of their organs, particularly the liver. These histopathological findings in Asah1(+/-) animals correlated with an up to twofold increase in the ceramide content of these tissues and a reduction n AC activity, confirming that the gene insertion event disrupted AC activity and ceramide metabolism. These results provide direct in vivo evidence that normal ceramide metabolism, and AC activity in particular, is essential for mammalian development. The animals and embryos described here should be a valuable resource for investigators studying the role of ceramide in cell growth and development, as well as those interested in the pathogenesis of FD and other sphingolipid storage disorders.
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Affiliation(s)
- Chi-Ming Li
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, USA
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