Cause of death in patients with chronic visceral and chronic neurovisceral acid sphingomyelinase deficiency (Niemann-Pick disease type B and B variant): Literature review and report of new cases

Natural history of acid sphingomyelinase deficiency among European patients during childhood and adolescence: A retrospective observational study

Acid sphingomyelinase deficiency (ASMD) is a rare, lysosomal storage disease with limited evidence on its natural history. This retrospective, medical record abstraction study aimed to characterize the natural history of ASMD (types B and A/B) during childhood and adolescence. Recruiting sites were European centers (i.e., France, Germany, Italy, and the United Kingdom) from the ASCEND-Peds trial (NCT02292654); these sites were targeted because of the rarity of ASMD and specialized care provided at these centers. The study population comprised ASMD trial patients (before exposure to treatment) and ASMD non-trial participants who were managed at the same trial sites. Overall, 18 patients were included (11 trials; 7 non-trials; median [Q1; Q3] age at ASMD diagnosis: 2.5 [1.0; 4.0] years). Median follow-up duration was 10.0 years. Frequently reported medical conditions were hepatobiliary (17 [94.4%]) and blood and lymphatic system disorders (16 [88.9%]). Adenoidectomy (3 [16.7%]) was the most commonly reported surgical procedures; gastroenteritis (5 [27.8%]) was the most frequently reported infections, and epistaxis (6 [33.3%]) was the most commonly reported bleeding events. Abnormal spleen (16 [88.9%]) and liver (15 [83.3%]) size and respiratory function (8 [44.4%]) were commonly reported during physical examination. Overall, 11 (61.1%) patients were hospitalized; 6 (33.3%) patients had emergency room visits. Findings were consistent with published literature and support the current understanding of natural history of ASMD.

The Etiologic Landscape of Lymphoproliferation in Childhood: Proposal for a Diagnostic Approach Exploring from Infections to Inborn Errors of Immunity and Metabolic Diseases

Lymphoproliferation is defined by lymphadenopathy, splenomegaly, hepatomegaly, or lymphocytic organ and tissue infiltration. The most common etiologies of lymphoproliferation are represented by infectious diseases and lymphoid malignancies. However, it is increasingly recognized that lymphoproliferative features can be the presenting sign of rare conditions, including inborn errors of immunity (IEI) and inborn errors of metabolism (IEM). Among IEI, lymphoproliferation is frequently observed in autoimmune lymphoproliferative syndrome (ALPS) and related disorders, common variable immunodeficiency (CVID), activated phosphoinositide 3-kinase δ syndrome, and Epstein-Barr virus (EBV)-related disorders. Gaucher disease and Niemann-Pick disease are the most common IEMs that can present with isolated lymphoproliferative features. Notably, other rare conditions, such as sarcoidosis, Castleman disease, systemic autoimmune diseases, and autoinflammatory disorders, should be considered in the differential diagnosis of patients with persistent lymphoproliferation when infectious and malignant diseases have been reasonably ruled out. The clinical features of lymphoproliferative diseases, as well as the associated clinical findings and data deriving from imaging and first-level laboratory investigations, could significantly help in providing the correct diagnostic suspicion for the underlying etiology. This paper reviews the most relevant diseases associated with lymphoproliferation, including infectious diseases, hematological malignancies, IEI, and IEM. Moreover, some practical indications to orient the initial diagnostic process are provided, and two diagnostic algorithms are proposed for the first-level assessment and the approach to persistent lymphoproliferation, respectively.

A retrospective study of morbidity and mortality of chronic acid sphingomyelinase deficiency in Germany

BACKGROUND

Acid sphingomyelinase deficiency (ASMD) is a rare, progressive, potentially fatal lysosomal storage disease that exhibits a broad spectrum of clinical phenotypes. There is a need to expand the knowledge of disease mortality and morbidity in Germany because of limited information on survival analysis in patients with chronic ASMD (type B or type A/B).

METHODS

This observational, multicentre, retrospective cohort study was conducted using medical records of patients with the first symptom onset/diagnosis of ASMD type B or type A/B between 1st January 1990 and 31st July 2021 from four German medical centres. Eligible medical records were abstracted to collect data on demographic characteristics, medical history, hospitalisation, mortality, and causes of death from disease onset to the last follow-up/death. Survival outcomes were estimated using the Kaplan-Meier analysis. Standardised mortality ratio (SMR) was also explored.

RESULTS

This study included 33 chart records of patients with ASMD type B (n = 24) and type A/B (n = 9), with a median (interquartile range [IQR]) age of 8.0 [3.0-20.0] years and 1.0 [1.0-2.0] years, respectively, at diagnosis. The commonly reported manifestations were related to spleen (100.0%), liver (93.9%), and respiratory (77.4%) abnormalities. Nine deaths were reported at a median [IQR] age of 17.0 [5.0-25.0] years, with 66.7% of overall patients deceased at less than 18 years of age; the median [IQR] age at death for patients with ASMD type B (n = 4) and type A/B (n = 5) was 31.0 [11.0-55.0] and 9.0 [4.0-18.0] years, respectively. All deaths were ASMD-related and primarily caused by liver or respiratory failures or severe progressive neurodegeneration (two patients with ASMD type A/B). The median (95% confidence interval [CI]) overall survival age since birth was 45.4 (17.5-65.0) years. Additionally, an SMR [95% CI] analysis (21.6 [9.8-38.0]) showed that age-specific deaths in the ASMD population were 21.6 times more frequent than that in the general German population.

CONCLUSIONS

This study highlights considerable morbidity and mortality associated with ASMD type B and type A/B in Germany. It further emphasises the importance of effective therapy for chronic ASMD to reduce disease complications.

Novel Mutation in Chromosome 11p15.4 Causing Niemann-Pick Disease Type A in a Saudi Child

Niemann-Pick disease (NPD) encompasses a minimum of three lysosomal storage diseases, all of which are inherited in an autosomal recessive manner. Acid sphingomyelinase (ASM) deficiency is the cause of NPD types A and B. ASM is the enzyme that hydrolyzes the sphingolipid sphingomyelin. An 18-month-old patient with progressive painless abdominal distension with organomegaly and neurological deficits presented to our hospital. Brain imaging and laboratory findings did not show anything, but there was a millstone growth delay. The diagnosis of NPD type A was confirmed by a genetic examination, which revealed a twofold change on chromosome 11p15.4 in the region encoding the sphingomyelin phosphodiesterase-1 (SMPD1) gene. The patient was followed up with no specific treatment, and signs of respiratory infections were later reported.

Diagnostic odyssey for patients with acid sphingomyelinase deficiency (ASMD): Exploring the potential indicators of diagnosis using quantitative and qualitative data

Acid sphingomyelinase deficiency (ASMD) is a rare, progressive, and potentially fatal lysosomal storage disease. This two-part international study aimed to understand physician, patient, and caregivers' experiences during the ASMD diagnostic journey. Qualitative interviews were conducted with patients with ASMD type B or A/B, caregivers (for patients <18 years), and physicians (January 2018-May 2019). A quantitative patient chart review was then performed by physicians (1-3 charts per physician) (April to May 2020). Overall, 12 physicians and 27 patients (self-reported, n = 11; caregiver-reported, n = 16) completed qualitative interviews. Symptoms first presented at approximately 2 years, with physician visits 2 months-1 year later. On average, diagnosis took 3 years and average age at diagnosis was 5 years. During childhood, all patients reported abdominal enlargement and 67% had respiratory issues. Adult patients frequently reported fatigue (64%) and heart problems (36%). In the quantitative study, 86 physicians reviewed 193 ASMD patient charts. At initial presentation, most patients reported abdominal enlargement (pediatric, 55%; adolescents/adults, 39%). Time to diagnosis ranged 0-10 years for patients with ASMD type A/B or type B, and most patients (85%) received an incorrect initial diagnosis. Diagnosis of ASMD can be challenging, and is often delayed due to disease heterogeneity and misdiagnoses.

Survival of patients with chronic acid sphingomyelinase deficiency (ASMD) in the United States: A retrospective chart review study

Background

Acid sphingomyelinase deficiency (ASMD), historically known as Niemann-Pick disease type A, A/B, and B, is a rare lysosomal storage pathology with multisystemic clinical manifestations. The aims of this study were to estimate the survival probability in patients in the United States with chronic ASMD (ASMD types B and A/B), and to describe the disease characteristics of these patients.

Methods

This observational retrospective study included medical chart records of patients with chronic ASMD with retrievable data abstracted by 69 participating physicians from 25 medical centers in the United States. Included patients had a date of ASMD diagnosis or first presentation to a physician for ASMD symptoms (whichever occurred first) between January 01, 1990, and February 28, 2021. Medical chart records were excluded if patients were diagnosed with ASMD type A. Eligible medical chart records were abstracted to collect demographic, medical and developmental history, and mortality data. Survival outcomes were analyzed using Kaplan-Meier survival analyses from birth until death.

Results

The overall study population (N = 110) included 69 patients with ASMD type B, nine with type A/B, and 32 with ASMD "non-type A" (ASMD subtype was unknown, but patients were confirmed as not having ASMD type A). The majority of patients were male with a median age at diagnosis of 3.8 years. Thirty-eight patients died during the study observation period, at a median age of 6.8 years. The median (95% confidence interval) survival age from birth was 21.3 (10.2; 60.4) years. At diagnosis or first presentation, 42.7% patients had ≥1 ASMD-related complication; splenic (30.0%) and hepatobiliary (20.9%) being the most common, and 40.9% required ≥1 medical visit due to complications.

Conclusion

Patients with chronic ASMD in the United States have poor survival and significant burden of illness.

The Genetic Basis, Lung Involvement, and Therapeutic Options in Niemann-Pick Disease: A Comprehensive Review

Niemann-Pick Disease (NPD) is a rare autosomal recessive disease belonging to lysosomal storage disorders. Three types of NPD have been described: NPD type A, B, and C. NPD type A and B are caused by mutations in the gene SMPD1 coding for sphingomyelin phosphodiesterase 1, with a consequent lack of acid sphingomyelinase activity. These diseases have been thus classified as acid sphingomyelinase deficiencies (ASMDs). NPD type C is a neurologic disorder due to mutations in the genes NPC1 or NPC2, causing a defect of cholesterol trafficking and esterification. Although all three types of NPD can manifest with pulmonary involvement, lung disease occurs more frequently in NPD type B, typically with interstitial lung disease, recurrent pulmonary infections, and respiratory failure. In this sense, bronchoscopy with broncho-alveolar lavage or biopsy together with high-resolution computed tomography are fundamental diagnostic tools. Although several efforts have been made to find an effective therapy for NPD, to date, only limited therapeutic options are available. Enzyme replacement therapy with Olipudase α is the first and only approved disease-modifying therapy for patients with ASMD. A lung transplant and hematopoietic stem cell transplantation are also described for ASMD in the literature. The only approved disease-modifying therapy in NPD type C is miglustat, a substrate-reduction treatment. The aim of this review was to delineate a state of the art on the genetic basis and lung involvement in NPD, focusing on clinical manifestations, radiologic and histopathologic characteristics of the disease, and available therapeutic options, with a gaze on future therapeutic strategies.

Real-life impacts of olipudase alfa: The experience of patients and families taking an enzyme replacement therapy for acid sphingomyelinase deficiency

BACKGROUND

Acid Sphingomyelinase Deficiency (ASMD) is an ultra-rare autosomal recessive lysosomal storage disorder characterized by intracellular lipid accumulation resulting from reduced function of acid sphingomyelinase. Olipudase alfa, an enzyme replacement therapy, was recently approved in several countries for the treatment of the non-neurologic manifestations of ASMD. Studies demonstrate improvement in organomegaly, pulmonary function and lipid profiles with olipudase alfa, yet little is known about its impact on quality of life (QoL) for patients and caregivers. The purpose of this study is to better understand the real-life impact of ASMD on patients and caregivers and assess how olipudase alfa impacts QoL for pediatric patients and their caregivers.

METHODS

Caregivers of pediatric patients (≤ 18 years of age) with a confirmed diagnosis of ASMD that received olipudase alfa for at least 12 months were recruited in early 2022 through national patient organizations to participate in a global online questionnaire followed by semi-structured interviews. Ten caregivers of patients with ASMD who utilized olipudase alfa as an experimental therapy for pediatric patients participated in the study. Quantitative analysis of the results was undertaken, and qualitative data was analyzed using an inductive thematic approach.

RESULTS

Ten eligible participants completed questionnaires, and 8 of the 10 went on to participate in structured interviews. Symptom burden of ASMD and impact on symptomatology and quality of life after olipudase alfa use are reported here. Five themes emerged from analysis: (1) ASMD is a systemic disease with a wide array of manifestations that significantly impact QoL; (2) Olipudase alfa was associated with improvements in all non-neurologic manifestations of ASMD; (3) Participants perceived the risk associated with olipudase alfa to be low and the benefits to greatly outweigh any risk or burden; (4) Participants reported an unmet need to treat the neurologic manifestations of the disease despite the benefits of olipudase alfa in the management of non-neurological symptoms; (5) Participants felt all patients with ASMD need access to olipudase alfa based on the life-changing experience they perceived.

CONCLUSIONS

These findings highlight the sustained positive impact olipudase alfa had in many domains that are deemed important to patients and families living with ASMD and outline the extensive unmet need for patients and families living with ASMD.

Continued improvement in disease manifestations of acid sphingomyelinase deficiency for adults with up to 2 years of olipudase alfa treatment: open-label extension of the ASCEND trial

BACKGROUND

Olipudase alfa is a recombinant human acid sphingomyelinase enzyme replacement therapy for non-central-nervous-system manifestations of acid sphingomyelinase deficiency (ASMD). The ASCEND randomized placebo-controlled trial in adults with ASMD demonstrated reductions in sphingomyelin storage, organomegaly, interstitial lung disease and impaired diffusion capacity of the lung (DLCO), during the first year of olipudase alfa treatment. In an ongoing open-label extension of the ASCEND trial, individuals in the placebo group crossed over to olipudase alfa, and those in the olipudase alfa group continued treatment.

RESULTS

Thirty-five of 36 participants continued in the extension trial, and 33 completed year 2. Change-from-baseline results are presented as least-square mean percent change ± SEM. Improvements in the cross-over group after 1 year of treatment paralleled those of the olipudase alfa group from the primary analysis, while clinical improvement continued for those receiving olipudase alfa for 2 years. In the cross-over group, percent-predicted DLCO increased by 28.0 ± 6.2%, spleen volume decreased by 36.0 ± 3.0% and liver volume decreased by 30.7 ± 2.5%. For those with 2 years of olipudase alfa treatment, the percent predicted DLCO increased by 28.5 ± 6.2%, spleen volume decreased by 47.0 ± 2.7%, and liver volume decreased by 33.4 ± 2.2%. Lipid profiles and elevated liver transaminase levels improved or normalized by 1 year and remained stable through 2 years of treatment. Overall, 99% of treatment-emergent adverse events were mild or moderate, with one treatment-related serious adverse event (extrasystoles; previously documented cardiomyopathy). No individual discontinued due to an adverse event.

CONCLUSION

Treatment with olipudase alfa is well tolerated and reduces manifestations of chronic ASMD with sustained efficacy. Trial registration NCT02004691 registered 9 December 2013, https://clinicaltrials.gov/ct2/show/NCT02004691.

Expert opinion on patient journey, diagnosis and clinical monitoring in acid sphingomyelinase deficiency in Turkey: a pediatric metabolic disease specialist's perspective

This review by a panel of pediatric metabolic disease specialists aimed to provide a practical and implementable guidance document to assist clinicians in best clinical practice in terms of recognition, diagnosis and management of patients with acid sphingomyelinase deficiency (ASMD). The participating experts consider the clinical suspicion of ASMD by the physician to be of utmost importance in the prevention of diagnostic delay and strongly suggest the use of a diagnostic algorithm including/starting with dried blood spots assay in the timely diagnosis of ASMD in patients presenting with hepatosplenomegaly and a need for increased awareness among physicians in this regard to consider ASMD in the differential diagnosis. In anticipation of the introduction of enzyme replacement therapy, raising awareness of the disease among physicians to prevent diagnostic delay and further investigation addressing natural history of ASMD across the disease spectrum, potential presenting characteristics with a high index of suspicion, as well as biomarkers and genotype-phenotype correlations suggestive of poor prognosis seem important in terms of implementation of best practice patterns.

Olipudase Alfa in Non-CNS Manifestations of Acid Sphingomyelinase Deficiency: A Profile of Its Use

Olipudase alfa (Xenpozyme™) is an intravenously administered acid sphingomyelinase enzyme replacement therapy indicated to treat non-CNS manifestations of acid sphingomyelinase deficiency (ASMD) in adult and paediatric patients. It is the first and currently the only disease-modifying treatment for ASMD. Olipudase alfa treatment improves hepatosplenomegaly, lung function and platelet counts, along with multiple other pathological features of ASMD in adult and paediatric patients with ASMD. These benefits are sustained through at least 24 months of treatment. Olipudase alfa is generally well tolerated; infusion-associated reactions (mostly mild) were the most common treatment-related adverse events. Other warnings and precautions associated with its use include risks of hypersensitivity reactions (including anaphylaxis) and elevated transaminase levels seen in clinical trials, and foetal malformation based on animal studies. All these risks are generally manageable. A gradual dose escalation of olipudase alfa, followed by a maintenance phase, is required to reduce the risks of toxic sphingomyelin catabolites build up, infusion-associated reactions and transient transaminase elevations.

Healthcare Service Use Patterns Among Patients with Acid Sphingomyelinase Deficiency Type B: A Retrospective US Claims Analysis

INTRODUCTION

Acid sphingomyelinase deficiency (ASMD) is a rare lysosomal storage disease. Patients with ASMD type B experience multiple morbidities, potentially leading to early mortality. Before the 2022 approval of olipudase alfa for non-neuronopathic ASMD manifestations, only symptom management was offered. Data on healthcare services used by patients with ASMD type B are limited. This analysis used medical claims data to evaluate real-world healthcare service use by patients with ASMD type B in the United States of America (USA).

METHODS

The IQVIA Open Claims patient-level database (2010-2019) was cross-examined. Two patient cohorts were identified: the primary analysis cohort, which included patients with at least two claims associated with ASMD type B (ICD-10 code E75.241) and more total claims with ASMD type B than any other ASMD types, and the sensitivity analysis cohort, which included patients with a high probability of having ASMD type B identified using a validated machine-learning algorithm. Claims for ASMD-associated healthcare services were recorded, including outpatient visits, emergency department (ED) visits, and inpatient hospitalizations.

RESULTS

The primary analysis cohort included 47 patients; a further 59 patients made up the sensitivity analysis cohort. Patient characteristics and healthcare service use were similar in both cohorts and were consistent with established characteristics of ASMD type B. Overall, 70% of the primary analysis cohort from this study were aged < 18 years, and the liver, spleen, and lungs were the most frequently affected organs. Cognitive, developmental, and/or emotional problems and respiratory/lung disorders caused most outpatient visits; respiratory/lung disorders accounted for most ED visits and hospitalizations.

CONCLUSION

This retrospective analysis of medical claims data identified patients with ASMD type B who had characteristics typical of this condition. A machine-learning algorithm detected further cases with a high probability of having ASMD type B. High use of ASMD-related healthcare services and medications was observed in both cohorts.

Olipudase alfa enzyme replacement therapy for acid sphingomyelinase deficiency (ASMD): sustained improvements in clinical outcomes after 6.5 years of treatment in adults

BACKGROUND

Enzyme replacement therapy with olipudase alfa, a recombinant human acid sphingomyelinase (rhASM), is indicated for non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in children and adults. An ongoing, open-label, long-term study (NCT02004704) assessed the safety and efficacy of olipudase alfa in 5 adults with ASMD.

RESULTS

After 6.5 years of treatment, there were no discontinuations, no olipudase-alfa-related serious adverse events, and no new safety signals compared to earlier assessments. Most treatment-emergent adverse events were mild in intensity (1742/1766, 98.6%). Among treatment-related adverse events (n = 657), more than half were considered infusion-associated reactions (n = 403, 61.3%) such as headache, nausea, abdominal pain, arthralgia, pyrexia, and fatigue. No patient developed neutralizing anti-drug antibodies to cellular uptake, and there were no clinically significant adverse changes in vital signs, hematology, or cardiac safety parameters. Improvements (decreases) in spleen and liver volumes progressed through 6.5 years (mean changes from baseline of -59.5% and  -43.7%, respectively). There was a mean increase in diffusing capacity of the lung for carbon monoxide from baseline of 55.3%, accompanied by improvements in interstitial lung disease parameters. Lipid profiles at baseline indicated dyslipidemia. All patients had sustained decreases in pro-atherogenic lipid levels and increases in anti-atherogenic lipid levels following olipudase alfa treatment.

CONCLUSIONS

Olipudase alfa is the first disease-specific treatment for ASMD. This study demonstrates that long-term treatment with olipudase alfa is well-tolerated and is associated with sustained improvements in relevant disease clinical measures. NCT02004704 registered 26 November 2013, https://clinicaltrials.gov/ct2/show/NCT02004704?term=NCT02004704&draw=2&rank=1 .

Consensus clinical management guidelines for acid sphingomyelinase deficiency (Niemann-Pick disease types A, B and A/B)

BACKGROUND

Acid Sphingomyelinase Deficiency (ASMD) is a rare autosomal recessive disorder caused by mutations in the SMPD1 gene. This rarity contributes to misdiagnosis, delayed diagnosis and barriers to good care. There are no published national or international consensus guidelines for the diagnosis and management of patients with ASMD. For these reasons, we have developed clinical guidelines that defines standard of care for ASMD patients.

METHODS

The information contained in these guidelines was obtained through a systematic literature review and the experiences of the authors in their care of patients with ASMD. We adopted the Appraisal of Guidelines for Research and Evaluation (AGREE II) system as method of choice for the guideline development process.

RESULTS

The clinical spectrum of ASMD, although a continuum, varies substantially with subtypes ranging from a fatal infantile neurovisceral disorder to an adult-onset chronic visceral disease. We produced 39 conclusive statements and scored them according to level of evidence, strengths of recommendations and expert opinions. In addition, these guidelines have identified knowledge gaps that must be filled by future research.

CONCLUSION

These guidelines can inform care providers, care funders, patients and their carers about best clinical practice and leads to a step change in the quality of care for patients with ASMD with or without enzyme replacement therapy (ERT).

Acid sphingomyelinase deficiency (ASMD): addressing knowledge gaps in unmet needs and patient journey in Italy-a Delphi consensus

Acid sphingomyelinase deficiency (ASMD) is an ultra-rare disease, and several gaps of knowledge on various issues remain, particularly at a regional/national level. Expert opinions collected through well-defined consensus methodologies are increasingly used to make available reliable information in the context of rare/ultra-rare diseases. With the aim to provide indications on infantile neurovisceral ASMD (also formerly known as Niemann-Pick disease type A), chronic neurovisceral ASMD (formerly known as Niemann-Pick disease type A/B) and chronic visceral ASMD (formerly known as Niemann-Pick disease type B) in Italy, we conducted a Delphi consensus of experts focused on five main areas: (i) patients and disease characteristics; (ii) unmet needs and quality of life; (iii) diagnostic issues; (iv) treatment-related aspects; and (v) patient journey. Pre-specified, objective criteria were used to outline the multidisciplinary panel, based on 19 Italian experts in ASMD in paediatric and adult patients from different Italian Regions, including both clinicians (n = 16) and ASMD patients' advocacy or payors with expertise in rare diseases (n = 3). During two Delphi rounds, a high ratio of agreement was found on several topics related to ASMD characteristics, diagnosis, management and disease burden. Our findings may provide valuable indications for management of ASMD at a public health level in Italy.

Enzyme replacement therapy for children with acid sphingomyelinase deficiency in the real world: A single center experience in Taiwan

Background

Acid sphingomyelinase deficiency (ASMD) is a lysosomal storage disease with multi-systemic involvement, with no disease-modifying treatment available. Olipudase alfa is an investigational enzyme product developed to replace the deficient acid sphingomyelinase in ASMD patients. Several clinical trials have reported promising safety and efficacy results in adult and pediatric patients. However, no data have been reported outside of the clinical trial setting yet. This study aimed to evaluate major outcomes in pediatric chronic ASMD patients receiving olipudase alfa in the real-world setting.

Materials and methods

Two children with type A/B (chronic neuropathic) ASMD have received olipudase alfa treatment since May 2021. Clinical parameters, including height, weight, complete blood count, liver function tests, lipid profiles, biomarkers, abdominal ultrasonography with shear wave elastography, chest computed tomography, nerve conduction studies, neurodevelopmental evaluations, and six-minute walk tests, were checked at baseline and every three to six months in the first year of enzyme replacement therapy (ERT) to assess its efficacy and safety.

Results

The two patients in our study started olipudase alfa treatment at the age of 5 years and 8 months and 2 years and 6 months. During the first year of treatment, both patients saw a reduction in their hepatic and splenic volumes as well as liver stiffness. Height z-score, weight z-score, lipid profiles, biomarker levels, interstitial lung disease scores, and bone mineral densities also improved over time. The six-minute walk test showed a gradual increase in walking distance in both patients. There were no obvious improvements or deterioration in neurocognitive function and peripheral nerve conduction velocities after treatment. No severe infusion-associated reactions were noted during the first year of treatment. One patient had two episodes of transient but significantly elevated liver enzymes during the dose-escalation phase. The patient was asymptomatic, and the impaired liver function resolved spontaneously within two weeks.

Conclusion

Our results provide real-world experience that olipudase alfa is safe and effective in improving major systemic clinical outcomes for pediatric chronic ASMD patients. Monitoring of liver stiffness by shear wave elastography is a noninvasive procedure that can monitor treatment efficacy during ERT.

SMPD1 gene variants in patients with β-Thalassemia major

BACKGROUND

β-thalassemia major and Niemann-Pick diseases have similar clinical and laboratory findings. We aimed to investigate the effects of sphingomyelin phosphodiesterase 1 (SMPD1) gene variants on the clinical and laboratory findings in patients with β-thalassemia major.

METHODS AND RESULTS

This study included 45 patients who were followed up for β-thalassemia major in our clinic. Plasma chitotriosidase, leukocyte acid sphingomyelinase, liver enzymes, ferritin, hemogram, biochemical parameters, SMPD1 gene variant analysis, cardiac T2* MRI, and liver R2 MRI were assessed in all patients. The SMPD1 gene c.132_143del, p.A46_L49del (c.108GCTGGC[4] (p.38AL[4])) (rs3838786) variant was detected in 9 of 45 (20.0%) patients. Plasma chitotriosidase, ferritin, acetyl aminotransferase, and alanine aminotransferase levels were significantly higher in patients with the gene variant than in those without (p < 0.05). Leukocyte acid sphingomyelinase levels were significantly lower in patients with the gene variant than in those without (p < 0.05).

CONCLUSION

These results imply that the clinical and laboratory findings and some features of disease progression in patients with β-thalassemia major are similar to those of Niemann-Pick disease. They also suggest that SMPD1 gene c.132_143del, p.A46_L49del (c.108GCTGGC[4] (p.38AL[4])) (rs3838786) variant may underlie these clinical findings in patients with β-thalassemia major.

Similarities and differences between Gaucher disease and acid sphingomyelinase deficiency: An algorithm to support the diagnosis

Lysosomal storage disorders are a group of inborn errors of metabolism due to defects in proteins crucial for lysosomal function. Gaucher disease is the most common autosomal recessive lysosomal storage disorder due to mutations in the GBA1 gene, resulting in the lysosomal deficiency of glucocerebrosidase activity. Gaucher disease is characterized by the toxic accumulation of glucosylceramide in the reticuloendothelial system. Acid sphingomyelinase deficiency (ASMD), previously known as Niemann Pick A/B disease, is also an autosomal recessive lysosomal storage disorder due to mutations in the SMPD1 gene, which result in acid sphingomyelinase deficiency and the accumulation of sphingomyelin in mononuclear phagocytic system and hepatocytes. The phenotypic expression of Gaucher disease type 1 (GD1), the most common type, and chronic visceral ASMD may overlap for several signs or symptoms. Splenomegaly is detectable in approximately 90% of the patients in both conditions; however, since GD1 is more frequent than ASMD, clinicians are more prone to suspect it, often neglecting the diagnosis of ASMD. Based on previous experience, a group of experts in the clinical and laboratory diagnosis, management, and treatment of lysosomal storage disorders developed an algorithm for both GD1 and ASMD to support physicians, including primary care providers, internists, and specialists (e.g., hepatologists, hematologists, and pulmonologists) to suspect and differentiate GD1 and ASMD and to provide the appropriate referral.

Niemann-Pick Disease: A Case Report and Literature Review

Niemann-Pick disease (NPD) A/B is a lysosomal storage disease (LSD), caused by an autosomal recessive disorder that causes variation in sphingomyelin phosphodiesterase-1 (SMPD1). Systemic signs are cholestatic jaundice in the neonatal period or hepatosplenomegaly in infancy. The clinical course experienced by our patient did not correspond to the classic phenotypes. The diagnosis was effectively made at four years and three months of age when different signs such as abdominal distension, hepatosplenomegaly, and chronic malnutrition were present. Given the high suspicion of metabolic storage disease, an enzyme activity study, liver and bone marrow biopsies, and molecular studies were performed. In the bone marrow biopsy, pseudo-Gaucher foam cells were observed. Additionally, the liver biopsy showed dispersed ballooned cells with deposit material and nested cells with granular material. The double enzymatic assay was ordered to determine if the cause of these findings was due to Niemann-Pick or Gaucher disease; decreased sphingomyelinase activity values were obtained (0.28 mcoml/L/h). Subsequently, the molecular genetics study reported a double alteration in the sequence that encodes the SMPD1 gene, located on chromosome 11p15.4, which confirmed NPD type A or B. The overlap and the lack of some findings made the diagnosis very difficult. Diagnosis is crucial due to the multisystem involvement that this LSD can have.

Long-term safety and clinical outcomes of olipudase alfa enzyme replacement therapy in pediatric patients with acid sphingomyelinase deficiency: two-year results

BACKGROUND

Olipudase alfa is a recombinant human acid sphingomyelinase (ASM) enzyme replacement therapy (ERT) for non-central-nervous-system manifestations of acid sphingomyelinase deficiency (ASMD). We report 2-year cumulative safety and efficacy data after olipudase alfa treatment in 20 children (four adolescents [12-17 year], nine children [6-11 year], and seven infants/early child [1-5 year]) with baseline splenomegaly and growth deficits who completed the 1-year ASCEND-Peds clinical trial (NCT02292654) and who continue to receive olipudase alfa in a long-term study (NCT02004704). Efficacy endpoints include spleen and liver volumes, diffusing capacity of the lung for carbon monoxide (DL_CO), high-resolution computed tomography (HRCT) lung imaging, lipid profiles, liver function tests, and height Z-scores.

RESULTS

All 20 former ASCEND-Peds patients completed at least 2 years of olipudase alfa treatment. No patient discontinued and no new safety issue arose during the second year of treatment; 99% of adverse events were mild or moderate. During year 2, one patient had two treatment-related serious events of hypersensitivity that resolved. Mean reductions from baseline in spleen and liver volumes were 61% and 49%, respectively (p < 0.0001) and mean percent-predicted-DL_CO increased by 46.6% (p < 0.0001) in nine patients who performed the test at baseline. Lipid profiles and elevated liver transaminase levels that improved or normalized by 1 year remained stable. Mean height Z-scores improved in all age groups (mean change from baseline 1.17, P < 0.0001).

CONCLUSION

Olipudase alfa was generally well-tolerated during 2 years of treatment. Improvements in clinically relevant disease endpoints observed during the first year of treatment were maintained or augmented in the second year. Trial registration NCT02004704 registered 26 Nov 2013, https://clinicaltrials.gov/ct2/show/record/NCT02004704 .

Successful Outcome of Pregnancy in Niemann-Pick Disease Type B: A Case Report and Review of Literature

Niemann-Pick (NPD) is a rare autosomal recessive disease, caused by deficiency of acid sphingomyelinase enzyme leading to accumulation of lipids mainly in the reticuloendothelial system and lungs. We describe the case of a 29-year-old primigravida, recently diagnosed with NPD type B. At initial evaluation, her platelets were normal, liver enzymes slightly elevated and splenomegaly on scan. Pregnancy care was by a multidisciplinary team which routinely monitored her liver and pulmonary functions along with platelets. Labor was induced at 37 + 1 weeks of gestation because of fetal growth restriction. She underwent an cesarean section for failed induction and delivered a healthy male baby. Conclusion: Successful outcomes in such pregnancies depend upon close monitoring by a multidisciplinary team.

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.

Health insurance literacy and health services access barriers in Niemann-Pick disease: the patient and caregiver voice

Background

Major challenges to health care access include low health insurance literacy, prohibitive costs, and insurance barriers. Niemann–Pick disease (NPD), comprising acid sphingomyelinase deficiency (ASMD) and Niemann–Pick type C (NPC), is a group of rare, autosomal recessive, highly heterogeneous, neurovisceral, life-threatening, relentlessly progressive lysosomal disorders. Patients experience debilitating systemic and neurological symptoms and substantial emotional and financial stress. Currently, these multifaceted disorders are managed symptomatically as there are no approved therapies. Given the considerable disease burden of NPD, timely access to quality health care is paramount for improving outcomes in these life-threatening disorders. Understanding health insurance literacy and access challenges among patients with NPD and their caregivers is a first step to overcoming treatment barriers.

Results

Patients from the Niemann–Pick community participated in a health insurance literacy survey and follow-up telephone interviews on perceived access challenges. Of the 79 respondents who completed the survey, 67 participated in interviews. All respondents had stable health insurance coverage. However, 61% of respondents were unaware of Medicaid waivers and did not avail of them. Overall, 50% of respondents with childhood onset NPC selected Medicaid/Medicare and private insurance; 35% utilized Medicaid waivers. Most respondents with ASMD had private insurance only. Although the Niemann–Pick community demonstrated greater health insurance literacy than the general population, knowledge gaps exist in calculating insurance coverage, out-of-pocket maximums, and defining a formulary. The most frequently cited access burden was the process of obtaining medical care and services. Among respondents with ASMD, the greatest access burden was fear of unavailability of or access to medications and treatment. Access challenges adversely impacted patients’ mental health and exacerbated physical symptoms. Delays and denials in obtaining essential medication, equipment, and services contributed to disease progression. Caregivers faced burnout and often questioned the utility of their advocacy.

Conclusions

This study identified knowledge gaps in health insurance literacy and challenges to access medication and health care services among individuals impacted by NPD. Patients and caregivers need the knowledge and skills to navigate a complicated health care system, understand their rights to medication and services and, ultimately, benefit from improved outcomes, especially in a post–drug approval era.

A randomized, placebo-controlled clinical trial evaluating olipudase alfa enzyme replacement therapy for chronic acid sphingomyelinase deficiency (ASMD) in adults: One-year results

PURPOSE

This trial aimed to assess the efficacy and safety of olipudase alfa enzyme replacement therapy for non-central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in adults.

METHODS

A phase 2/3, 52 week, international, double-blind, placebo-controlled trial (ASCEND; NCT02004691/EudraCT 2015-000371-26) enrolled 36 adults with ASMD randomized 1:1 to receive olipudase alfa or placebo intravenously every 2 weeks with intrapatient dose escalation to 3 mg/kg. Primary efficacy endpoints were percent change from baseline to week 52 in percent predicted diffusing capacity of the lung for carbon monoxide and spleen volume (combined with splenomegaly-related score in the United States). Other outcomes included liver volume/function/sphingomyelin content, pulmonary imaging/function, platelet levels, lipid profiles, and pharmacodynamics.

RESULTS

Least square mean percent change from baseline to week 52 favored olipudase alfa over placebo for percent predicted diffusing capacity of the lung for carbon monoxide (22% vs 3.0% increases, P = .0004), spleen volume (39% decrease vs 0.5% increase, P < .0001), and liver volume (28% vs 1.5% decreases, P < .0001). Splenomegaly-related score decreased in both groups (P = .64). Other clinical outcomes improved in the olipudase alfa group compared with the placebo group. There were no treatment-related serious adverse events or adverse event-related discontinuations. Most adverse events were mild.

CONCLUSION

Olipudase alfa was well tolerated and associated with significant and comprehensive improvements in disease pathology and clinically relevant endpoints compared with placebo in adults with ASMD.

Acid Sphingomyelinase Deficiency: Sharing Experience of Disease Monitoring and Severity in France

Acid sphingomyelinase deficiency (ASMD) is a rare inherited lipid storage disorder caused by a deficiency in lysosomal enzyme acid sphingomyelinase which results in the accumulation of sphingomyelin, predominantly within cells of the reticuloendothelial system located in numerous organs, such as the liver, spleen, lungs, and central nervous system. Although all patients with ASMD share the same basic metabolic defect, a wide spectrum of clinical presentations and outcomes are observed, contributing to treatment challenges. While infantile neurovisceral ASMD (also known as Niemann-Pick disease type A) is rapidly progressive and fatal in early childhood, and the more slowly progressive chronic neurovisceral (type A/B) and chronic visceral (type B) forms have varying clinical phenotypes and life expectancy. The prognosis of visceral ASMD is mainly determined by the association of hepatosplenomegaly with secondary thrombocytopenia and lung disease. Early diagnosis and appropriate management are essential to reduce the risk of complications and mortality. The accessibility of the new enzyme replacement therapy olipudase alfa, a recombinant human ASM, has been expedited for clinical use based on positive clinical data in children and adult patients, such as improved respiratory status and reduced spleen volume. The aim of this article is to share the authors experience on monitoring ASMD patients and stratifying the severity of the disease to aid in care decisions.

Prevalence of Cancer in Acid Sphingomyelinase Deficiency

Acid sphingomyelinase deficiency (ASMD) is an inherited lysosomal disease characterised by a diffuse accumulation of sphingomyelin that cannot be catabolised into ceramide and phosphocholine. We studied the incidence of cancer in ASMD patients. We retrospectively reviewed the medical records of the adult chronic visceral ASMD patients in our cohort. Thirty-one patients (12 females, 19 males) were included with a median age of 48.7 y. (IQ: 30.3–55.1). Five cancers were observed in 1 female (breast cancer) and 4 males (two lung cancers, one thyroid cancer and one bladder cancer), resulting in a prevalence of 16.1%. The existence of cancer was associated with a more severe ASMD characterised by a larger spleen (25 cm (22.5–25) vs. 18 cm (17–20); p = 0.042); lower diffusing capacity of the lung for carbon monoxide (DLCO; 29.5 % (17.8–43.0) vs. 58.5 % (49.8–69.5%); p = 0.01) and tobacco use (100% vs. 45%; p = 0.04). Three patients died, all from cancer (p = 0.002). The prevalence of cancer appeared to be strikingly elevated in our cohort of patients, without any specificity in the type of cancer. Systematic screening for cancer should be performed, and carcinogenic substances such as tobacco should be avoided in patients with ASMD.

Focal hepatic lesions in acid sphingomyelinase deficiency: Differential diagnosis between foamy macrophages aggregates and malignancy

Acid sphingomyelinase deficiency (ASMD) is a rare metabolic disorder due to biallelic mutation in the SMPD1 gene. The defect leads to the accumulation of sphingomyelin within the cells of the reticulo-endothelial system, particularly in the spleen, liver, lungs, and bone marrow causing hepato-splenomegaly, lung disease and hematological abnormalities. At present, data on abdominal imaging in ASMD are limited. Here we describe the characteristics of focal liver lesions observed in a 30 years old female. During the Magnetic Resonance follow up an increase in number and size of the lesions, showing T1 hypointensity and T2 hyperintensity with contrast enhancement, was observed. Contrast enhanced ultrasound evidenced rapid wash-in and steady isoecogenicity without appreciable wash-out at 80 seconds. The main lesion was biopsied to rule out the presence of a hepatocellular carcinoma, and showed to be a benign foamy macrophages aggregate. In this report, we discuss the possible pathogenesis of focal hepatic lesions in ASMD and their differential diagnosis.

Altered Macrophage Function Associated with Crystalline Lung Inflammation in Acid Sphingomyelinase Deficiency

Deficiency of ASM (acid sphingomyelinase) causes the lysosomal storage Niemann-Pick disease (NPD). Patients with NPD type B may develop progressive interstitial lung disease with frequent respiratory infections. Although several investigations using the ASM-deficient (ASMKO) mouse NPD model revealed inflammation and foamy macrophages, there is little insight into the pathogenesis of NPD-associated lung disease. Using ASMKO mice, we report that ASM deficiency is associated with a complex inflammatory phenotype characterized by marked accumulation of monocyte-derived CD11b⁺ macrophages and expansion of airspace/alveolar CD11c⁺ CD11b^- macrophages, both with increased size, granularity, and foaminess. Both the alternative and classical pathways were activated, with decreased in situ phagocytosis of opsonized (Fc-coated) targets, preserved clearance of apoptotic cells (efferocytosis), secretion of Th2 cytokines, increased CD11c⁺/CD11b⁺ cells, and more than a twofold increase in lung and plasma proinflammatory cytokines. Macrophages, neutrophils, eosinophils, and noninflammatory lung cells of ASMKO lungs also exhibited marked accumulation of chitinase-like protein Ym1/2, which formed large eosinophilic polygonal Charcot-Leyden-like crystals. In addition to providing insight into novel features of lung inflammation that may be associated with NPD, our report provides a novel connection between ASM and the development of crystal-associated lung inflammation with alterations in macrophage biology.

Prospective study of the natural history of chronic acid sphingomyelinase deficiency in children and adults: eleven years of observation

Background

Acid sphingomyelinase deficiency (ASMD) (also known as Niemann-Pick disease types A and B) is a rare and debilitating lysosomal storage disorder. This prospective, multi-center, multinational longitudinal study aimed to characterize the clinical features of chronic forms of ASMD and disease burden over time in children and adults.

Results

Fifty-nine patients (31 males/28 females) ranging in age from 7 to 64 years with chronic ASMD types A/B and B and at least two disease symptoms participated from 5 countries. Disease characteristics were assessed at baseline, after 1 year, and at the final visit (ranging from 4.5 to 11 years). Thirty patients (51%) were < 18 years at baseline (median age 12 years), and 29 were adults (median age 32 years). Overall, 32/59 patients completed the final visit, 9 died, 9 discontinued, and 9 were lost to follow up. Common clinical characteristics that tended to worsen gradually with time were splenomegaly, hepatomegaly, interstitial lung disease, lung diffusion capacity (DL_CO), and dyslipidemia. Spleen volumes ranged from 4 to 29 multiples of normal at baseline, and splenomegaly was moderate or severe in 86%, 83%, and 90% of individuals at baseline, year 1, and final visits, respectively. The proportion of all individuals with interstitial lung disease was 66% (39/59) at baseline and 78% (25/32) at the final visit, while median % predicted DL_CO decreased by > 10% from baseline to the final visit. Nine patients died (15%), eight of causes related to ASMD (most commonly pneumonia); of these eight patients, five (63%) had symptom onset at or before age 2. Overall, six of the nine deaths occurred before age 50 with three occurring before age 20. Individuals with either severe splenomegaly or prior splenectomy were ten times more likely to have died during the follow-up period than those with smaller or intact spleens (odds ratio 10.29, 95% CI 1.7, 62.7). Most children had growth deficits that persisted into adulthood.

Conclusions

This study provides important information about the natural history of chronic ASMD and provides a longitudinal view of the spectrum of disease manifestations and major morbidities in children and adults and supports the selection of clinically meaningful endpoints in therapeutic trials.

Sphingolipid lysosomal storage diseases: from bench to bedside

Johann Ludwig Wilhelm Thudicum described sphingolipids (SLs) in the late nineteenth century, but it was only in the past fifty years that SL research surged in importance and applicability. Currently, sphingolipids and their metabolism are hotly debated topics in various biochemical fields. Similar to other macromolecular reactions, SL metabolism has important implications in health and disease in most cells. A plethora of SL-related genetic ailments has been described. Defects in SL catabolism can cause the accumulation of SLs, leading to many types of lysosomal storage diseases (LSDs) collectively called sphingolipidoses. These diseases mainly impact the neuronal and immune systems, but other systems can be affected as well. This review aims to present a comprehensive, up-to-date picture of the rapidly growing field of sphingolipid LSDs, their etiology, pathology, and potential therapeutic strategies. We first describe LSDs biochemically and briefly discuss their catabolism, followed by general aspects of the major diseases such as Gaucher, Krabbe, Fabry, and Farber among others. We conclude with an overview of the available and potential future therapies for many of the diseases. We strive to present the most important and recent findings from basic research and clinical applications, and to provide a valuable source for understanding these disorders.

Interstitial lung disease in lysosomal storage disorders

Lysosomes are intracellular organelles that are responsible for degrading and recycling macromolecules. Lysosomal storage diseases (LSDs) are a group of inherited diseases caused by mutations affecting genes that encode the function of the lysosomal enzymes. Three LSDs are associated with lung involvement and/or interstitial lung disease (ILD): Gaucher disease (GD); Niemann-Pick disease, also known as acid sphingomyelinase deficiency (ASMD); and Fabry disease (FD). In GD and in ASMD, analysis of bronchoalveolar lavage fluid and lung biopsy can be informative, showing foamy cells. In GD, ILD is rare. Enzyme replacement therapy (ERT) has been available since 1991 and has greatly changed the natural history of GD, with pulmonary failure and death reported before the ERT era. In ASMD, ILD is frequent and is usually associated with spleen enlargement, low platelet cell count and low level of high-density lipoprotein-cholesterol. Results of ERT are promising regarding preliminary results of olipudase alfa in paediatric and adult ASMD populations. The most frequent respiratory manifestation in FD is COPD-like symptoms regardless of smoking habit and dyspnoea due to congestive heart failure. Early diagnosis of these three LSDs is crucial to prevent irreversible organ damage. Early initiation of ERT can, at least in part, prevent organ failure.

One-year results of a clinical trial of olipudase alfa enzyme replacement therapy in pediatric patients with acid sphingomyelinase deficiency

Purpose

To assess olipudase alfa enzyme replacement therapy for non–central nervous system manifestations of acid sphingomyelinase deficiency (ASMD) in children.

Methods

This phase 1/2, international, multicenter, open-label trial (ASCEND-Peds/NCT02292654) administered intravenous olipudase alfa every 2 weeks with intrapatient dose escalation to 3 mg/kg. Primary outcome was safety through week 64. Secondary outcomes included pharmacokinetics, spleen and liver volumes, lung diffusing capacity (DL_CO), lipid profiles, and height through week 52.

Results

Twenty patients were enrolled: four adolescents (12–17 years), nine children (6–11 years), and seven infants/early child (1–5 years). Most adverse events were mild or moderate, including infusion-associated reactions (primarily urticaria, pyrexia, and/or vomiting) in 11 patients. Three patients had serious treatment-related events: one with transient asymptomatic alanine aminotransferase increases, another with urticaria and rash (antidrug antibody positive [ADA+]), and a third with an anaphylactic reaction (ADA+) who underwent desensitization and reached the 3 mg/kg maintenance dose. Mean splenomegaly and hepatomegaly improved by >40% (p < 0.0001). Mean % predicted DL_CO improved by 32.9% (p = 0.0053) in patients able to perform the test. Lipid profiles and elevated liver transaminase levels normalized. Mean height Z-scores improved by 0.56 (p < 0.0001).

Conclusion

In this study in children with chronic ASMD, olipudase alfa was generally well-tolerated with significant, comprehensive improvements in disease pathology across a range of clinically relevant endpoints.

Pulmonary Manifestations of Endocrine and Metabolic Diseases in Children

Advances in technology, methodology, and deep phenotyping are increasingly driving the understanding of the pathologic basis of disease. Improvements in patient identification and treatment are impacting survival. This is true in endocrinology and inborn errors of metabolism, where disease-modifying therapies are developing. Inherent to this evolution is the increasing awareness of the respiratory manifestations of these rare diseases. This review updates clinicians, stratifying diseases spirometerically; pulmonary hypertension and diseases with a predisposition to recurrent pulmonary infection are discussed. This division is artificial; many diseases have multiple pathologic effects on respiration. This review does not cover the impact of obesity.

Keep Your Friends Close, but Your Enemies Closer: Role of Acid Sphingomyelinase During Infection and Host Response

Breakdown of the inert and constitutive membrane building block sphingomyelin to the highly active lipid mediator ceramide by extracellularly active acid sphingomyelinase is tightly regulated during stress response and opens the gate for invading pathogens, triggering the immune response, development of remote organ failure, and tissue repair following severe infection. How do one enzyme and one mediator manage all of these affairs? Under physiological conditions, the enzyme is located in the lysosomes and takes part in the noiseless metabolism of sphingolipids, but following stress the protein is secreted into circulation. When secreted, acid sphingomyelinase (ASM) is able to hydrolyze sphingomyelin present at the outer leaflet of membranes to ceramide. Its generation troubles the biophysical context of cellular membranes resulting in functional assembly and reorganization of proteins and receptors, also embedded in highly conserved response mechanisms. As a consequence of cellular signaling, not only induction of cell death but also proliferation, differentiation, and fibrogenesis are affected. Here, we discuss the current state of the art on both the impact and function of the enzyme during host response and damage control. Also, the potential role of lysosomotropic agents as functional inhibitors of this upstream alarming cascade is highlighted.

Renal Thrombotique microangiopathy: An unusual renal involvement in Niemann-Pick disease type B

Renal involvement in Niemann-Pick disease type B is very rare. Kidney check-up and renal biopsy should be performed in any patient presented with hypertension and kidney disease. Histology identifies the lesion, the prognosis, and guide treatment.

Sphingomyelinases and Liver Diseases

Sphingolipids (SLs) are critical components of membrane bilayers that play a crucial role in their physico-chemical properties. Ceramide is the prototype and most studied SL due to its role as a second messenger in the regulation of multiple signaling pathways and cellular processes. Ceramide is a heterogeneous lipid entity determined by the length of the fatty acyl chain linked to its carbon backbone sphingosine, which can be generated either by de novo synthesis from serine and palmitoyl-CoA in the endoplasmic reticulum or via sphingomyelin (SM) hydrolysis by sphingomyelinases (SMases). Unlike de novo synthesis, SMase-induced SM hydrolysis represents a rapid and transient mechanism of ceramide generation in specific intracellular sites that accounts for the diverse biological effects of ceramide. Several SMases have been described at the molecular level, which exhibit different pH requirements for activity: neutral, acid or alkaline. Among the SMases, the neutral (NSMase) and acid (ASMase) are the best characterized for their contribution to signaling pathways and role in diverse pathologies, including liver diseases. As part of a Special Issue (Phospholipases: From Structure to Biological Function), the present invited review summarizes the physiological functions of NSMase and ASMase and their role in chronic and metabolic liver diseases, of which the most relevant is nonalcoholic steatohepatitis and its progression to hepatocellular carcinoma, due to the association with the obesity and type 2 diabetes epidemic. A better understanding of the regulation and role of SMases in liver pathology may offer the opportunity for novel treatments of liver diseases.

Clinical relevance of endpoints in clinical trials for acid sphingomyelinase deficiency enzyme replacement therapy

BACKGROUND

Acid sphingomyelinase deficiency (ASMD) also known as Niemann-Pick disease, is a rare lysosomal storage disorder with a diverse disease spectrum that includes slowly progressive, chronic visceral (type B) and neurovisceral forms (intermediate type A/B), in addition to infantile, rapidly progressive fatal neurovisceral disease (type A).

PURPOSE AND METHODS

We review the published evidence on the relevance of splenomegaly and reduced lung diffusion capacity to the clinical burden of chronic forms of ASMD. Targeted literature searches were conducted to identify relevant ASMD and non-ASMD studies for associations between diffusing capacity of the lungs for carbon monoxide (DL_CO) and splenomegaly, with clinical parameters and outcome measures.

RESULTS

Respiratory disease and organomegaly are primary and independent contributors to mortality, disease burden, and morbidity for patients with chronic ASMD. The degree of splenomegaly correlates with short stature, atherogenic lipid profile, and degree of abnormality of hematologic parameters, and thus may be considered a surrogate marker for bleeding risk, abnormal lipid profiles and possibly, liver fibrosis. Progressive lung disease is a prevalent clinical feature of chronic ASMD, contributing to a decreased quality of life (QoL) and an increased disease burden. In addition, respiratory-related complications are a major cause of mortality in ASMD.

CONCLUSIONS

The reviewed evidence from ASMD natural history and observational studies supports the use of lung function and spleen volume as clinically meaningful endpoints in ASMD trials that translate into important measures of disease burden for patients.

Combined Emphysema and Interstitial Lung Disease as a Rare Presentation of Pulmonary Involvement in a Patient with Chronic Visceral Acid Sphingomyelinase Deficiency (Niemann-Pick Disease Type B)

BACKGROUND Niemann-Pick disease is a rare genetic disorder caused by mutations in sphingomyelin phosphodiesterase 1 gene. It results in acid sphingomyelinase deficiency (ASMD) and sphingomyelin intracellular accumulation. Lung disease is diagnosed mostly in chronic visceral ASMD. Ground-glass opacities and smooth interlobular septal thickening are described most frequently. They are localized predominantly in the lower parts of both lungs. CASE REPORT The authors describe a rare type of lung involvement, composed of emphysema and interstitial lung disease (ILD), in a nonsmoking adult male with chronic visceral ASMD. Areas of ground-glass opacities and lung fibrosis presenting as reticulation and bronchiectasis have been described in high-resolution computed tomography of the lungs. The radiological findings were localized predominantly in the middle and lower parts of both lungs. Large air spaces of marginal emphysema, localized in the upper lobes, were also demonstrated. Foamy macrophages, staining blue with May-Grünwald-Giemsa, were found in bronchoalveolar lavage, confirming lung involvement in the course of ASMD. The course of disease was stable, with no hypoxemia at rest. Nevertheless, because of markedly decreased lung transfer for carbon monoxide and significant desaturation on exertion, further controls have been planned, with qualification for long-term oxygen therapy in case of deterioration. CONCLUSIONS We present a unique type of lung involvement, combined emphysema and ILD, in a nonsmoking adult patient with chronic visceral ASMD. On such occasion chronic obstructive pulmonary disease coexisting with ILD as well as chronic pulmonary fibrosis and emphysema syndrome should be excluded.

Biochemical and imaging parameters in acid sphingomyelinase deficiency: Potential utility as biomarkers

Acid Sphingomyelinase Deficiency (ASMD), or Niemann-Pick type A/B disease, is a rare lipid storage disorder leading to accumulation of sphingomyelin and its precursors primarily in macrophages. The disease has a broad phenotypic spectrum ranging from a fatal infantile form with severe neurological involvement (the infantile neurovisceral type) to a primarily visceral form with different degrees of pulmonary, liver, spleen and skeletal involvement (the chronic visceral type). With the upcoming possibility of treatment with enzyme replacement therapy, the need for biomarkers that predict or reflect disease progression has increased. Biomarkers should be validated for their use as surrogate markers of clinically relevant endpoints. In this review, clinically important endpoints as well as biochemical and imaging markers of ASMD are discussed and potential new biomarkers are identified. We suggest as the most promising biomarkers that may function as surrogate endpoints in the future: diffusion capacity measured by spirometry, spleen volume, platelet count, low-density lipoprotein cholesterol, liver fibrosis measured with a fibroscan, lysosphingomyelin and walked distance in six minutes. Currently, no biomarkers have been validated. Several plasma markers of lipid-laden cells, fibrosis or inflammation are of high potential as biomarkers and deserve further study. Based upon current guidelines for biomarkers, recommendations for the validation process are provided.

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.

Pulmonary involvement in selected lysosomal storage diseases and the impact of enzyme replacement therapy: A state-of-the art review

Lysosomal storage disorders (LSDs) are multisystemic, progressive and clinically very heterogeneous. Respiratory complications are not regarded as the principal problems of LSDs, but significantly impact morbidity. In this review, we focus on pulmonary complications observed in late-onset LSDs, their milder forms that are recognised in adulthood. We also discuss the effects of enzyme replacement therapy (ERT) on the respiratory system in patients with particular LSDs. We searched the PubMed database, retrieving research papers on pulmonary complications of LSDs currently treated with ERT (the conditions are abbreviated GD3; NPDB; LOPD; MPS I, II, IVA, VI; and FD) and the effects of such treatment. Although some studies indicated that ERT was helpful in terms of reducing chest computed tomography abnormalities, infection frequency and organomegaly, the data are not conclusive, and the mechanism of action of ERT in the respiratory system remains unclear for some LSDs including late-onset Pompe disease and Gaucher disease type III. The optimal timing of treatment for pre-symptomatic or symptomatic patients, treatment duration and whether such treatment modulates inflammation (as has been suggested in patients with Fabry disease), remain to be explored.

Respiratory complications of metabolic disease in the paediatric population: A review of presentation, diagnosis and therapeutic options

Inborn errors of metabolism (IEMs) whilst individually rare, as a group constitute a field which is increasingly demands on pulmonologists. With the advent of new therapies such as enzyme replacement and gene therapy, early diagnosis and treatment of these conditions can impact on long term outcome, making their timely recognition and appropriate investigation increasingly important. Conversely, with improved treatment, survival of these patients is increasing, with the emergence of previously unknown respiratory phenotypes. It is thus important that pulmonologists are aware of and appropriately monitor and manage these complications. This review aims to highlight the respiratory manifestations which can occur. It isdivided into conditions resulting primarily in obstructive airway and lung disease, restrictive lung disease such as interstitial lung disease or pulmonary alveolar proteinosis and pulmonary hypertension, whilst acknowledging that some diseases have the potential to cause all three. The review focuses on general phenotypes of IEMs, their known respiratory complications and the basic metabolic investigations which should be performed where an IEM is suspected.

Pulmonary Type B Niemann-Pick Disease Successfully Treated with Lung Transplantation

Background

Niemann-Pick Disease (NPD) type B is a rare autosomal recessive disease characterised by hepatosplenomegaly and pulmonary disease, highlighted by preserved volumes and diminished diffusion capacity of the lung for carbon monoxide (DLCO) on pulmonary function tests (PFTs). There is no current accepted treatment for the disease. We present a case of a successful bilateral lung transplant in a patient with a DLCO of 14%, and significant pulmonary changes attributable to NPD type B on computed tomography (CT) chest, and both microscopic and macroscopic assessment of the lung explant. To the author's knowledge this is only the third case of lung transplantation in a patient with NPD type B and is one of two current living patients post lung transplantation for NPD type B.

Case Report

A 64-year-old male patient underwent bilateral lung transplantation for NPD type B. Preoperative PFTs demonstrated preserved volumes with significantly decreased DLCO, with imaging showing a diffuse reticular interstitial pattern, typical of chronic fibrotic lung disease. The patient suffered from primary graft dysfunction type 3 in the postoperative period as well as rejection managed with methylprednisolone and intravenous immunoglobulin. The patient improved steadily and was discharged 80 days post-transplantation.

Conclusions

This case is only the third reported case of lung transplantation in a patient with NPD type B and the second case of a patient with NPD type B currently living post-transplantation, being at postoperative day (POD) 267 at the time of manuscript drafting. It demonstrates that lung transplantation, although hazardous, is a viable strategy for treatment in patients with NPD type B who have significant pulmonary involvement.

Respiratory impairment in Niemann-Pick B disease: Two case reports and review for the pulmonologist

Acid sphingomyelinase deficiency (ASMD), also called Niemann-Pick disease, is a storage disorder with pulmonary involvement but few respiratory symptoms in adults. However, the disease may evolve towards clinically relevant respiratory symptoms with referral to the pulmonologist for management and care. Based on two case reports illustrating respiratory impairment, the aim of this work was to review clinical features, diagnosis, respiratory prognostic and therapeutics for the pulmonologist. Overall, storage disorder should be suspected in the presence of hepatosplenomegaly and interstitial lung disease. Concomitant thrombopenia or hyperlipidemia should also draw attention. Following recent consensus guidelines, diagnosis is based on enzyme assay for ASM activity in blood, with subsequent gene sequencing once the biochemical diagnosis has been confirmed. Disease is slowly progressive and the main causes of death are respiratory and liver failure. Presence of emphysema lesions or worsening of respiratory symptoms should call for the intensification of treatment. Though enzyme replacement therapy is a promising way of development, lung transplantation might be considered for these patients in the absence of contraindication.

Case Report of Gastrointestinal Bleeding in an Adult with Chronic Visceral Acid Sphingomyelinase Deficiency

Introduction

Acid sphingomyelinase deficiency (ASMD, also known as Niemann-Pick Type A and Type B disease) is a rare, inherited metabolic disorder. Liver-related issues, including cirrhosis and variceal haemorrhage, are a leading cause of early mortality in individuals with chronic forms of ASMD. Due to the rarity of this lysosomal storage disorder, there can be a lack of awareness that adults with chronic ASMD disease are at significant risk of cirrhosis, portal hypertension, and variceal bleeding. This case highlights an unusual presentation of recurrent variceal bleeding in an adult with cirrhosis and portal hypertension due to chronic visceral ASMD.

Case Presentation

A patient with severe splenomegaly was diagnosed with ASMD at age of 25. At age 64 they had multiple hospital admissions for hematochezia (originally diagnosed as ischemic colitis) accompanied by hypotension (blood pressure 91/45 mmHg), anemia (hemoglobin 8.5g/dL, ref 12-16; INR 1.4, ref ≤1.2), and mild renal insufficiency (creatinine 1.33mg/dL, ref 0.51-0.95). Colonoscopy did not reveal a source of bleeding. Computerized tomography scanning imaging showed diffuse venous collaterals and ascites. Arteriographies during subsequent episodes of bleeding were negative for active arterial intestinal bleeding. Recurrent gastrointestinal bleeding was found to originate from a varicose vein cluster connected to the right iliac vein and the superior mesenteric vein, located in the submucosa of a small intestinal loop. Multiple varices were secondary to portal hypertension in the context of cirrhosis. The patient died from recurrent variceal bleeding that exacerbated liver failure worsened by pneumonia and hypovolemic and septic shock.

Conclusions

The variceal bleeding in this patient was atypical in that it originated from venous collaterals bleeding into the small intestine rather than the more typical gastroesophageal varices observed in ASMD. With long standing liver dysfunction and gradual development of portal hypertension, intestinal varices rather than occult intestinal bleeding due to ischemia should be considered in ASMD patients presenting with either hematochezia or hematemesis.

Chronic visceral acid sphingomyelinase deficiency (Niemann-Pick disease type B) in 16 Polish patients: long-term follow-up

BACKGROUND

Acid sphingomyelinase deficiency (ASMD), due to mutations in the sphingomyelin phosphodiesterase 1 (SMPD1) gene, is divided into infantile neurovisceral ASMD (Niemann-Pick type A), chronic neurovisceral ASMD (intermediate form, Niemann-Pick type A/B) and chronic visceral ASMD (Niemann-Pick type B). We conducted a long-term observational, single-center study including 16 patients with chronic visceral ASMD.

RESULTS

12 patients were diagnosed in childhood and 4 others in adulthood, the oldest at the age of 50. The mean time of follow-up was approximately 10 years (range: 6 months - 36 years). Splenomegaly was noted in all patients at diagnosis. Hepatomegaly was observed in 88% of patients. Moderately elevated (several-fold above the upper limit of normal values) serum transaminases were noted in 38% of patients. Cherry-red spots were found in five Gypsy children from one family and also in one adult Polish patient, a heterozygote for p.delR610 mutation. Dyslipidemia was noted in 50% of patients. Interstitial lung disease was diagnosed in 44% of patients. Plasmatic lysosphingomyelin (SPC) was elevated in all the patients except one with p.V36A homozygosity and a very mild phenotype also presenting with elevated plasmatic SPC-509 but normal chitotriosidase activity. The most common variant of SMPD1 gene was p.G166R. We found a previously unreported variant in exon 2 (c.491G > T, p.G164 V) in one patient.

CONCLUSIONS

Chronic visceral ASMD could constitute a slowly progressing disease with a relatively good outcome. The combined measurement of lysosphingomyelin (SPC) and lysospingomyelin-509 (SPC-509) is an essential method for the assessment of ASMD course.

Recommendations for clinical monitoring of patients with acid sphingomyelinase deficiency (ASMD)

BACKGROUND

Acid sphingomyelinase deficiency (ASMD), a rare lysosomal storage disease, results from mutations in SMPD1, the gene encoding acid sphingomyelinase (ASM). As a result, sphingomyelin accumulates in multiple organs including spleen, liver, lung, bone marrow, lymph nodes, and in the most severe form, in the CNS and peripheral nerves. Clinical manifestations range from rapidly progressive and fatal infantile neurovisceral disease, to less rapidly progressing chronic neurovisceral and visceral forms that are associated with significant morbidity and shorter life span due to respiratory or liver disease.

OBJECTIVES

To provide a contemporary guide of clinical assessments for disease monitoring and symptom management across the spectrum of ASMD phenotypes.

METHODS

An international group of ASMD experts in various research and clinical fields used an evidence-informed consensus process to identify optimal assessments, interventions, and lifestyle modifications.

RESULTS

Clinical assessment strategies for major organ system involvement, including liver, spleen, cardiovascular, pulmonary, and neurological/developmental are described, as well as symptomatic treatments, interventions, and/or life style modifications that may lessen disease impact.

CONCLUSIONS

There is currently no disease-specific treatment for ASMD, although enzyme replacement therapy with a recombinant human ASM (olipudase alfa) is in clinical development. Current monitoring addresses symptoms and multisystem involvement. Recommended interventions and lifestyle modifications are designed to address morbidity and disease complications and improve patient quality of life. While infantile neurovisceral ASMD is uniformly fatal in early childhood, patients with chronic visceral and chronic neurovisceral ASMD require appropriate management throughout childhood and adulthood by an interdisciplinary clinical team.