Pompe disease is an inherited lysosomal storage disorder caused by acid alpha-glucosidase (GAA) enzyme deficiency, resulting in muscle and neuron intralysosomal glycogen storage. Clinical symptoms vary from the severe, infantile-onset form with hypertrophic cardiomyopathy, gross motor delay, and early death from respiratory insufficiency; to a late-onset form with variable onset of proximal muscle weakness and progressive respiratory insufficiency. Newborn screening programs have been instituted to presymptomatically identify neonates with infantile-onset Pompe disease for early initiation of treatment. However, infants with late-onset Pompe disease are also identified, leaving families and physicians in a state of uncertainty regarding prognosis, necessity, and timing of treatment initiation. This report presents a 31 5/7 weeks' gestational age premature infant flagged positive for Pompe disease with low dried blood spot GAA activity; sequencing identified biparental c.-32-13T>G/c.29delA GAA variants predicting late-onset Pompe disease. The infant's parents' initial reactions to the positive newborn screen, subsequent experience during confirmatory testing, and post-confirmation reflections are also reported. While uncertainties regarding natural history and prognosis of presymptomatically-identified late-onset Pompe disease infants will be elucidated with additional experience, suggestions for education of first-line providers are provided to accurately communicate results and compassionately counsel families regarding anxiety-provoking positive newborn screen results.

Mucopolysaccharidosis type VII (MPS VII) is caused by β-glucuronidase deficiency, resulting in lysosomal accumulation of glycosaminoglycans (GAGs) and multisystemic disease. We present cardiovascular gross and histopathology findings from a 11-year-old MPS VII male, who expired after developing ventricular fibrillation following anesthesia induction. Gross anatomic observations were made at autopsy; postmortem formalin-fixed paraffin-embedded samples of the carotid artery, aorta, myocardium, and valves were sectioned and stained with hematoxylin-eosin, Verhoeff-Van Gieson, CD68, and trichrome stains. Gross heart findings include an enlarged, dilated heart, mitral valve prolapse with thick, shortened chordae tendinae, and thickened aortic valve cusps. The aorta contained raised intimal plaques mimicking conventional atherosclerosis. Cardiac myocytes included hypertrophic nuclei, subendocardial fibrosis, and increased interfascicular collagen. Coronary lumens were 40-70% stenosed by fibrointimal hyperplasia containing storage material-laden cells, CD68⁺ macrophages, and fragmented elastin laminae. Similar findings were visualized in aortic intimal plaques. We confirm that arterial plaques, elastin fragmentation, and activated CD68⁺ macrophage infiltration occur in human MPS VII, consistent with previously observed findings in murine and canine MPS VII. We also confirm ultrasonographically observed carotid intimal-medial thickening is an in vivo correlate of histopathologic vascular fibrointimal hyperplasia. MPS VII patients should be regularly monitored for cardiac disease, with methods such as Holter monitors and stress testing; MPS VII-directed treatments should effectively address cardiovascular disease.

INTRODUCTION: High sustained anti-rhGAA antibody titers (HSAT; ≥12,800) are directly linked to reduced efficacy of enzyme replacement therapy (ERT) and subsequent clinical deterioration in infantile-onset Pompe disease (IOPD). We have previously demonstrated the safety and effectiveness of a bortezomib-based immune-tolerance induction (ITI) regimen (bortezomib, rituximab, methotrexate, and IVIG) in eliminating HSAT. METHODS: Here, we describe two IOPD cases (patients 6 and 8) who developed HSAT at 8 and 10 weeks on ERT despite transient low-dose methotrexate ITI administration in the ERT-naïve setting and were treated with a bortezomib-based ITI regimen, and we compare their courses to a series of six historical patients (patients 1-5, and 7) with a similar presentation who exemplify our evolving approach to treatment. RESULTS: In total, patients 6 and 8 received 16 and 8 doses of bortezomib (4 doses=1 cycle) respectively reducing titers from 25,600 to seronegative, but differences in the course of their therapy were instructive regarding the optimal approach to initial treatment of HSAT; specifically, patient 6 was treated initially with only a single course of bortezomib rescue therapy, while patient 8 received two back-to-back courses. Patient 8 received IVIG therapy throughout the immunosuppression whereas patient 6 received IVIG therapy and was switched to subcutaneous IgG replacement. Patient 6 had a transient reduction in anti-rhGAA antibodies, after receiving a single initial cycle of bortezomib, but had a recurrence of high anti-rhGAA antibody titer after 160 weeks that required 3 additional cycles of bortezomib to ultimately achieve tolerance. In contrast, patient 8 achieved tolerance after being given two consecutive cycles of bortezomib during their initial treatment and had B cell recovery by week 54. Since the reduction in anti-rhGAA antibodies, both patients are doing well clinically, and have decreasing ALT, AST, and CK. No major infections leading to interruption of treatment were observed in either patient. The bortezomib-based ITI was safe and well-tolerated, and patients continue to receive ERT at 40 mg/kg/week. DISCUSSION: These case studies and our previous experience suggest that to achieve an effective reduction of anti-rhGAA antibodies in the setting of HSAT, bortezomib should be initiated at the earliest sign of high anti-rhGAA antibodies with a minimum of two consecutive cycles as shown in the case of patient 8. It is important to note that, despite initiation of ERT at age 2.3 weeks, patient 8 quickly developed HSAT. We recommend close monitoring of anti-rhGAA antibodies and early intervention with ITI as soon as significantly elevated anti-rhGAA antibody titers are noted.

In this case series, we demonstrate that Ursodeoxycholic acid (UDCA) improves liver dysfunction in Niemann-Pick type C (NPC) and may restore a suppressed cytochrome p450 system. NPC disease is a progressive neurodegenerative lysosomal storage disease caused by mutations in either the NPC1 or NPC2 genes. Liver disease is a common feature presenting either acutely as cholestatic jaundice in the neonatal period, or in later life as elevated liver enzymes indicative of liver dysfunction. Recently, an imbalance in bile acid synthesis in a mouse model of NPC disease was linked to suppression of the P450 detoxification system and was corrected by UDCA treatment. UDCA (3α, 7β-dihydroxy-5β-cholanic acid), a hydrophilic bile acid, is used to treat various cholestatic disorders. In this report we summarise the findings from four independent cases of NPC, three with abnormal liver enzyme levels at baseline, that were subsequently treated with UDCA. The patients differed in age and clinical features, they all tolerated the drug well, and in those with abnormal liver function, there were significant improvements in their liver enzyme parameters.

Pompe disease is an autosomal recessive lysosomal storage disease caused by pathogenic variants in GAA, which encodes an enzyme integral to glycogen catabolism, acid α-glucosidase. Disease-relevant cell lines are necessary to evaluate the efficacy of genotype-specific therapies. Dermal fibroblasts from two patients presenting clinically with Pompe disease were reprogrammed to induced pluripotent stem cells using the Sendai viral method. One patient is compound heterozygous for the c.258dupC (p.N87QfsX9) frameshift mutation and the c.2227C>T (p.Q743X) nonsense mutation. The other patient harbors the c.-32-13T>G splice variant and the c.1826dupA (p.Y609X) frameshift mutation in compound heterozygosity.

Background

Niemann-Pick Disease Type C (NPC) is an inherited, often fatal neurovisceral lysosomal storage disease characterized by cholesterol accumulation in every cell with few known treatments. Defects in cholesterol transport cause sequestration of unesterified cholesterol within the endolysosomal system. The discovery that systemic administration of hydroxypropyl-beta cyclodextrin (HPβPD) to NPC mice could release trapped cholesterol from lysosomes, normalize cholesterol levels in the liver, and prolong life, led to expanded access use in NPC patients. HPβCD has been administered to NPC patients with approved INDs globally since 2009.

Results

Here we present safety, tolerability and efficacy data from 12 patients treated intravenously (IV) for over 7 years with HPβCD in the US and Brazil. Some patients subsequently received intrathecal (IT) treatment with HPβCD following on average 13 months of IV HPβCD. Several patients transitioned to an alternate HPβCD. Moderately affected NPC patients treated with HPβCD showed slowing of disease progression. Severely affected patients demonstrated periods of stability but eventually showed progression of disease. Neurologic and neurocognitive benefits were seen in most patients with IV alone, independent of the addition of IT administration. Physicians and caregivers reported improvements in quality of life for the patients on IV therapy. There were no safety issues, and the drug was well tolerated and easy to administer.

Conclusions

These expanded access data support the safety and potential benefit of systemic IV administration of HPβCD and provide a platform for two clinical trials to study the effect of intravenous administration of HPβCD in NPC patients.

Bioactive immunomodulatory biomaterials have shown promise for influencing the immune response to promote tissue repair and regeneration. Macrophages and T cells have been associated with this response; however, other immune cell types have been traditionally overlooked. In this study, we investigated the role of mast cells in the regulation of the immune response to decellularized biomaterial scaffolds using a subcutaneous implant model. In mast cell-deficient mice, there was dysregulation of the expected M1 to M2 macrophage transition typically induced by the biomaterial scaffold. Polarization progression deviated in a sex-specific manner with an early transition to an M2 profile in female mice, while the male response was unable to properly transition past a pro-inflammatory M1 state. Both were reversed with adoptive mast cell transfer. Further investigation of the later-stage immune response in male mice determined a greater sustained pro-inflammatory gene expression profile, including the IL-1 cytokine family, IL-6, alarmins, and chemokines. These results highlight mast cells as another important cell type that influences the immune response to pro-regenerative biomaterials.