A biallelic variant in COX18 cause isolated Complex IV deficiency associated with neonatal encephalo-cardio-myopathy and axonal sensory neuropathy

Pathogenic variants impacting upon assembly of mitochondrial respiratory chain Complex IV (Cytochrome c Oxidase or COX) predominantly result in early onset mitochondrial disorders often leading to CNS, skeletal and cardiac muscle manifestations. The aim of this study is to describe a molecular defect in the COX assembly factor gene COX18 as the likely cause of a neonatal form of mitochondrial encephalo-cardio-myopathy and axonal sensory neuropathy. The proband is a 19-months old female displaying hypertrophic cardiomyopathy at birth and myopathy with axonal sensory neuropathy and failure to thrive developing in the first months of life. Serum lactate was consistently increased. Whole exome sequencing allowed the prioritization of the unreported homozygous substitution NM_001297732.2:c.667 G > C p.(Asp223His) in COX18. Patient's muscle biopsy revealed severe and diffuse COX deficiency and striking mitochondrial abnormalities. Biochemical and enzymatic studies in patient's myoblasts and in HEK293 cells after COX18 silencing showed a severe impairment of both COX activity and assembly. The biochemical defect was partially rescued by delivery of wild-type COX18 cDNA into patient's myoblasts. Our study identifies a novel defect of COX assembly and expands the number of nuclear genes involved in a mitochondrial disorder due to isolated COX deficiency.

Parents' experience of the communication process of positivity at newborn screening for metabolic diseases: A qualitative study

BACKGROUND

The process of receiving a communication of positivity for metabolic diseases at expanded newborn screening (ENBS) is extremely articulated, involves a variety of actors (parents, maternal and child departments, clinical centres and laboratories) and is open to a variety of outcomes from false positive to true positive cases. Receiving communication of positivity can be highly stressful for parents and requires an adequate communication process to give clear and reliable information without causing excessive worry. This qualitative study describes the parents' experience of receiving a communication of positivity to metabolic diseases at ENBS, and their assessment of the quality of the communication process and steps, with the main aim to identify the process' strengths and weaknesses and to advance tailored recommendations to improve the communication process.

METHOD

Fourteen in-depth, semi-structured phone interviews were conducted with parents whose children resulted positive to the ENBS. As part of the ENBS communication process, parents received a first phone call communication of positivity and a second in-person communication at metabolic clinical centres (MCC). The framework analysis method was used to organize the data and identify emerging themes.

RESULTS

Parents were largely dissatisfied with the quality and depth of the information received and with the way the healthcare staff delivered the first communication phone call, which failed to create a caring, empathic and safe setting. Many parents tried to reduce the uncertainty by searching online information or consulting with other providers. Nevertheless, the majority of parents described the in-person visit at MCC as clear, welcoming and reassuring.

CONCLUSION

More efforts are needed to improve the quality of the communication process of the ENBS. Guidelines, recommendations and standard scripts to communicate positivity are needed along with programmes and educational resources to train tailored communication skills.

Hyperammonemia Syndrome After Lung Transplantation: A Double-Hit Fatal Syndrome. A Case Report

Hyperammonemia after lung transplantation is a rare but potentially fatal condition. A 59-year-old male patient affected by pulmonary fibrosis underwent an uncomplicated bilateral lung transplant. Fourteen days after the procedure, the patient developed severe encephalopathy caused by elevated serum ammonia levels. Ureaplasma parvum and Mycoplasma hominis were found on bronchial aspirate and urinary samples as well as on pharyngeal and rectal swabs. Despite the initiation of multimodal therapy, brain damage due to hyperosmolarity was so extensive to evolve into brain death. The autopsy revealed glutamine synthetase hypo-expression in the hepatic tissue. The pathophysiology of hyperammonemia syndrome in lung transplant recipients remains unclear. Previous studies have described the presence of disorders of glutamine synthetase, while others considered the infection with urea-splitting microorganisms as a cause of hyperammonemia syndrome. Our report describes the case of a patient who developed hyperammonemia after a lung transplant in which both the aforementioned etiologies were documented. A high level of clinical suspicion for hyperammonemia syndrome should be maintained in lung transplant recipients. Timely recognition and treatment are critical to prevent the potentially dreadful evolution of this severe complication.

Expanded Newborn Screening in Italy Using Tandem Mass Spectrometry: Two Years of National Experience

Newborn screening (NBS) for inborn errors of metabolism is one of the most advanced tools for secondary prevention in medicine, as it allows early diagnosis and prompt treatment initiation. The expanded newborn screening was introduced in Italy between 2016 and 2017 (Law 167/2016; DM 13 October 2016; DPCM 12-1-2017). A total of 1,586,578 infants born in Italy were screened between January 2017 and December 2020. For this survey, we collected data from 15 Italian screening laboratories, focusing on the metabolic disorders identified by tandem mass spectrometry (MS/MS) based analysis between January 2019 and December 2020. Aminoacidemias were the most common inborn errors in Italy, and an equal percentage was observed in detecting organic acidemias and mitochondrial fatty acids beta-oxidation defects. Second-tier tests are widely used in most laboratories to reduce false positives. For example, second-tier tests for methylmalonic acid and homocysteine considerably improved the screening of CblC without increasing unnecessary recalls. Finally, the newborn screening allowed us to identify conditions that are mainly secondary to a maternal deficiency. We describe the goals reached since the introduction of the screening in Italy by exchanging knowledge and experiences among the laboratories.

POS0640 REAL-WORLD EFFECTIVENESS AND SAFETY OF GP2015 IN PATIENTS WITH RHEUMATIC DISEASES: FINAL RESULTS OF THE COMPACT STUDY

Background

COMPACT is a non-interventional study evaluating the effectiveness and safety in patients (pts) with rheumatoid arthritis (RA), axial-spondyloarthritis (axSpA) or psoriatic arthritis (PsA) treated with GP2015 (an etanercept [ETN] biosimilar) in real-world conditions.

Objectives

We present the effectiveness and safety data from the final analysis of the COMPACT study for all patient groups.

Methods

Pts aged ≥18 years on treatment with GP2015 were enrolled. Baseline visit corresponded with date of study inclusion and not with date of GP2015 treatment start. Pts were categorised based on prior treatment status: pts on clinical remission or low disease activity under treatment with reference ETN or biosimilar ETN (initial ETN: [iETN]) and switched to GP2015 (Group A) or pts who received non-ETN targeted therapies and switched to GP2015 (Group B) or biologic-naïve pts who started GP2015 after conventional therapy failure (Group C) or DMARD-naïve pts with recent diagnosis of RA considered suitable for treatment initiation with a biologic and started on treatment with GP2015 (Group D). Effectiveness assessments included Disease Activity Score 28-joint count Erythrocyte Sedimentation Rate (DAS28-ESR) or Ankylosing Spondylitis Disease Activity Score (ASDAS) until Month 12 after enrolment (baseline) in the study.

Results

Of the 1466 pts enrolled, 572 were switched from iETN (Group A), 171 were switched from other targeted therapies (Group B), 713 were biologic-naïve (Group C), and 10 were RA DMARD-naïve (Group D). Comorbidities were more frequent in pts with RA (68.7%,) followed by pts with PsA (59.4%) and axSpA (52.1%). After 12 months of treatment with GP2015, pts with RA or PsA achieved comparable DAS28-ESR scores irrespective of whether they switched from iETN, or from other targeted therapies or were biologic-naïve. At Month 12, the mean ASDAS scores were comparable between the treatment groups in pts with axSpA (Table 1). Across all pt groups, no major differences were observed in the disease activity scores between baseline and Month 12 that may be explained by the ongoing GP2015 treatment at the time of enrolment for an observed average of 138 days. Overall, the proportion of patients with at least one adverse event (AE) and serious AE (SAE) was 47.6% and 7.7% in pts who were switched from iETN, 56.7% and 9.9% in pts switched from other targeted therapies, 56% and 8.7% in biologic-naïve pts, and 60% and 0% in DMARD-naïve pts. Rate of injection site reaction was low across the groups (Figure 1).

Table 1.

Effectiveness outcomes in patients treated with GP2015

Effectiveness outcomesGroup AGroup BGroup CGroup DOverall (A-D)RADAS28-ESR, n, mean (SD)N=295N=88N=451N=10N=844Baselinen=259n=70n=392n=8n=7292.5 (1.1)3.6 (1.3)3.3 (1.5)3.8 (1.2)3.0 (1.4)Month 12n=135n=47n=238n=2n=4222.5 (1.3)2.7 (1.0)2.8 (1.4)4.3 (2.5)2.7 (1.3)PsAN=117N=36N=135N=0N=288Baselinen=80n=30n=116-n=2262.1 (1.0)2.9 (1.6)2.9 (1.6)2.6 (1.5)Month 12n=32n=13n=60-n=1052.6 (1.9)2.6 (1.6)2.3 (1.4)2.4 (1.5)AxSpAASDAS, n, mean (SD)N=160N=47N=127N=0N=334Baselinen=77n=18n=59-n=1541.6 (0.6)1.8 (0.8)2.3 (0.9)1.9 (0.8)Month 12n=39n=8n=23-n=701.8 (0.9)1.9 (0.6)1.9 (1.0)1.8 (0.9)

N, total number of patients in the treatment group; n, number of patients with available data at each time point, SD, standard deviation

Figure 1.

Overall safety outcomes in patients treated with GP2015

Figure 1 represents the adverse events reported during GP2015 treatment.

N, total number of patients in the treatment; n, number of patients in each treatment group

Conclusion

The results show comparable disease activity scores between pts who were switched from iETN, pts switched from other targeted therapies and biologic-naïve pts after 12 months of treatment with GP2015. No impact on the effectiveness of ETN was observed in pts with RA, axSpA or PsA who switched to GP2015. No new safety signals were reported.

Disclosure of Interests

Marc Schmalzing Speakers bureau: Novartis, AbbVie, Chugai/Roche, Janssen-Cilag, Lilly, Consultant of: AstraZeneca, Chugai/Roche, Hexal/Sandoz, Gilead, AbbVie, Janssen-Cilag, Boehringer/Ingelheim, Grant/research support from: Chugai/Roche, Boehringer/Ingelheim, Celgene, Medac, Herbert Kellner: None declared, Ayman Askari: None declared, Javier de Toro Santos: None declared, JULIO CESAR VAZQUEZ PEREZ-COLEMAN Speakers bureau: Sandoz, Abbvie, Sanofi, Fresenius, Rosario Foti Speakers bureau: Abbivie, Gilead, Lilly, Pfizer, UCB, Roche, Novartis, Pfizer, UCB, Sławomir Jeka: None declared, Boulos Haraoui Consultant of: Abbvie, Amgen, Fresenius Kabi, Lilly and Pfizer, Grant/research support from: Abbvie, Amgen, Fresenius Kabi, Lilly and Pfizer, Yannick Allanore Consultant of: Sandoz Hexal, Mylan, Astra-Zeneca, Masiur Rahman Employee of: Sandoz Hexal AG, Fabricio Furlan Employee of: Sandoz Hexal AG, Sohaib HACHAICHI Employee of: Sandoz Hexal AG, Tom Sheeran Speakers bureau: Pfizer, UCB, Roche, Consultant of: Novartis, Pfizer, Grant/research support from: Novartis, UCB, Roche

PRDX1 gene-related epi-cblC disease is a common type of inborn error of cobalamin metabolism with mono- or bi-allelic MMACHC epimutations

Background

The role of epigenetics in inborn errors of metabolism (IEMs) is poorly investigated. Epigenetic changes can contribute to clinical heterogeneity of affected patients but could also be underestimated determining factors in the occurrence of IEMs. An epigenetic cause of IEMs has been recently described for the autosomal recessive methylmalonic aciduria and homocystinuria, cblC type (cblC disease), and it has been named epi-cblC. Epi-cblC has been reported in association with compound heterozygosity for a genetic variant and an epimutation at the MMACHC locus, which is secondary to a splicing variant (c.515-1G > T or c.515-2A > T) at the adjacent PRDX1 gene. Both these variants cause aberrant antisense transcription and cis-hypermethylation of the MMACHC gene promotor with subsequent silencing. Until now, only nine epi-cblC patients have been reported.

Methods

We report clinical/biochemical assessment, MMACHC/PRDX1 gene sequencing and genome-wide DNA methylation profiling in 11 cblC patients who had an inconclusive MMACHC gene testing. We also compare clinical phenotype of epi-cblC patients with that of canonical cblC patients.

Results

All patients turned out to have the epi-cblC disease. One patient had a bi-allelic MMACHC epimutation due to the homozygous PRDX1:c.515-1G > T variant transmitted by both parents. We found that the bi-allelic epimutation produces the complete silencing of MMACHC in the patient’s fibroblasts. The remaining ten patients had a mono-allelic MMACHC epimutation, due to the heterozygous PRDX1:c.515-1G > T, in association with a mono-allelic MMACHC genetic variant. Epi-cblC disease has accounted for about 13% of cblC cases diagnosed by newborn screening in the Tuscany and Umbria regions since November 2001. Comparative analysis showed that clinical phenotype of epi-cblC patients is similar to that of canonical cblC patients.

Conclusions

We provide evidence that epi-cblC is an underestimated cause of inborn errors of cobalamin metabolism and describe the first instance of epi-cblC due to a bi-allelic MMACHC epimutation. MMACHC epimutation/PRDX1 mutation analyses should be part of routine genetic testing for all patients presenting with a metabolic phenotype that combines methylmalonic aciduria and homocystinuria.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01117-2.

Genotype and residual enzyme activity in medium-chain acyl-CoA dehydrogenase (MCAD) deficiency: Are predictions possible?

Medium-chain acyl-CoA dehydrogenase deficiency (MCADD) is the most common defect of mitochondrial β-oxidation. Confirmation diagnostics after newborn screening (NBS) can be performed either by enzyme testing and/or by sequencing of the ACADM gene. Here, we report the results from enzyme testing in lymphocytes with gene variants from molecular analysis of the ACADM gene and with the initial acylcarnitine concentrations in the NBS sample. From April 2013 to August 2019, in 388 individuals with characteristic acylcarnitine profiles suggestive of MCADD the octanoyl-CoA-oxidation was measured in lymphocytes. In those individuals with residual activities <50%, molecular genetic analysis of the ACADM gene was performed. In 50% of the samples (195/388), MCADD with a residual activity ranging from 0% to 30% was confirmed. Forty-five percent of the samples (172/388) showed a residual activity >35% excluding MCADD. In the remaining 21 individuals, MCAD residual activity ranged from 30% to 35%. The latter group comprised both heterozygous carriers and individuals carrying two gene variants on different alleles. Twenty new variants could be identified and functionally classified based on their effect on enzyme function. C6 and C8 acylcarnitine species in NBS correlated with MCAD activity and disease severity. MCADD was only confirmed in half of the cases referred suggesting a higher false positive rate than expected. Measurement of the enzyme function in lymphocytes allowed fast confirmation diagnostics and clear determination of the pathogenicity of new gene variants. There is a clear correlation between genotype and enzyme function underlining the reproducibility of the functional measurement in vitro.

POS0608 SWITCHING OF TREATMENT FROM REFERENCE ETANERCEPT TO SANDOZ ETANERCEPT BIOSIMILAR IN PATIENTS WITH RHEUMATIC DISEASES: AN INTERIM ANALYSIS OF REAL-WORLD DATA FROM THE COMPACT STUDY

Background:

Sandoz etanercept (SDZ ETN) is a biosimilar of etanercept (ETN). COMPACT is an ongoing, non-interventional study, evaluating the effectiveness, safety, and quality of life with SDZ ETN treatment in patients (pts) with rheumatoid arthritis (RA), axial-spondyloarthritis (axSpA) or psoriatic arthritis (PsA) in real-world conditions.

Objectives:

We have reported an interim analysis, with the effectiveness and safety data focusing on pts who were in clinical remission or low disease activity under treatment with reference ETN or biosimilar ETN other than SDZ ETN (initial ETN; iETN) and switched to SDZ ETN.

Methods:

Pts aged ≥18 years for whom treatment with SDZ ETN were initiated are being enrolled. Pts were categorized under four treatment groups based on prior treatment status: Group A,

pts on clinical remission or low disease activity under treatment with iETN and switched to SDZ ETN; Group B, pts who received targeted therapies and switched to SDZ ETN; Group C, biologic naïve considered uncontrolled with conventional therapy; Group D, DMARD naïve with recent diagnosis of RA considered suitable for treatment initiation with a biologic and started on treatment with SDZ ETN. Effectiveness assessments included Disease Activity Score 28-joint count Erythrocyte Sedimentation Rate (DAS28-ESR) or Ankylosing Spondylitis Disease Activity Score (ASDAS) until Week 24 after enrollment (baseline; BL) in the study. Functional disability was measured by the Health Assessment Questionnaire Disability Index (HAQ-DI). The effectiveness and safety results are reported for the pts who switched from iETN (Group A).

Results:

Of the 1437 pts recruited (analysis cut-off date: 16 Oct, 2020), 567 pts were switched from iETN, 163 were switched from other targeted therapies, 697 were biologic-naïve, and 10 were RA DMARD-naïve. Among pts who switched from iETN, 51.5% had RA, followed by axSpA (28.0%) and PsA (20.5%). Comorbidities were more frequent in pts with RA (70.2%) followed by PsA (58.6%) and axSpA (49.7%); musculoskeletal and connective tissue disorders were reported in 31.8% and 15.7% of pts with RA and axSpA, respectively. At BL, whilst receiving iETN, the mean (SD) DAS28-ESR scores were 2.5 (1.1) and 2.1 (1.1) in pts with RA and PsA, respectively (figure 1). The mean change from BL in DAS28-ESR score at Week 24 after switch to SDZ ETN was -0.1 (1.1) and 0 (1.0) in pts with RA and PsA, respectively. In pts with axSpA, the mean (SD) ASDAS score was 1.5 (0.7) at BL; mean change from BL in ASDAS score at Week 24 was 0.1 (0.5). At BL, the mean (SD) HAQ-DI scores were 0.8 (0.7), 0.5 (0.7) and 0.5 (0.6) in pts with RA, PsA and axSpA, respectively. Overall, the proportion of patients with at least one adverse event (AE) was 37.3%, 33.6% and 25.8% in pts with RA, PsA and axSpA, respectively. Serious AEs were reported in 6.5%, 1.7% and 3.1% of pts with RA, PsA, and axSpA, respectively. Injections site reactions were reported in 2.7%, 0.9% and 1.3% of pts with RA, PsA and axSpA, respectively.

Figure 1.

Disease activity in patients who switched from iETN to SDZ ETN

Conclusion:

The interim analysis results shows that switch from iETN to SDZ ETN does not impact the effectiveness of ETN in pts with RA, axSpA or PsA, without any new safety signals.

Disclosure of Interests:

Marc Schmalzing Speakers bureau: Novartis, AbbVie, Chugai/Roche, Janssen-Cilag, Lilly, Consultant of: AstraZeneca, Chugai/Roche, Hexal/Sandoz, Gilead, AbbVie, Janssen-Cilag, Boehringer/Ingelheim, Grant/research support from: Travel grants: Chugai/Roche, Boehringer/Ingelheim, Celgene, Medac, Ayman Askari: None declared, Tom Sheeran Speakers bureau: Pfizer, UCB, Roche, Consultant of: Novartis, Pfizer, Grant/research support from: Novartis, UCB, Roche, David Walsh: None declared, Javier de Toro Santos: None declared, JULIO CESAR VAZQUEZ PEREZ-COLEMAN Speakers bureau: Sandoz, Abbvie, Sanofi, Fresenius, Charlotte Both Employee of: Sandoz employee Global Medical Affairs, Fabricio Furlan Employee of: Sandoz employee Global Medical Affairs, Sohaib HACHAICHI Employee of: Sandoz employee Global Medical Affairs, Herbert Kellner: None declared

AB0208 DO LOW CONCENTRATIONS OF CITRATE IN AN ADALIMUMAB FORMULATION IMPACT THE INCIDENCE AND/OR INTENSITY OF INJECTION SITE PAIN? DATA FROM PHASE I AND III STUDIES ASSESSING THE LOCAL TOLERANCE OF GP2017 (ADALIMUMAB BIOSIMILAR, SDZ-ADL) IN HEALTHY VOLUNTEERS, RHEUMATOID ARTHRITIS, AND PSORIASIS PATIENTS

Background:

Adalimumab (ADL) is typically self-administered every 2 weeks (W) as a subcutaneous (s.c.) injection by patients (pts) for diverse indications, including rheumatoid arthritis (RA), psoriatic arthritis (PsA), and psoriasis (PsO). Conflicting evaluations of local tolerance to formulations containing citrate buffer have created insecurities among health care professionals and pts.1,2

Objectives:

To evaluate local tolerance of SDZ-ADL (GP2017), a biosimilar ADL with low citrate concentration (1.2 mM),3 in 466 healthy volunteers (HV) and 408 pts (RA: 177 and PsO: 231 including PsA: 52) from four phase I pharmacokinetic (PK) and two phase III confirmatory studies.

Methods:

HV evaluated their injection site pain (ISP) using a Visual Analogue Scale (VAS) of 0–100 mm. HV received a single 40 mg/0.8 mL s.c. injection and pts received SDZ-ADL every 2W during 48–51W duration of study. Injection site reactions (ISR) as well as adverse events (AEs) were assessed by investigators during the clinical studies. Details of study designs have been reported previously.4–7

Results:

Overall, 456 (97.9%) HV experienced no ISR. Ten HV experienced ISR. These were mostly of mild intensity; only 1 (0.2%) had an ISR of moderate intensity. 96.6% of HV experienced no pain (VAS score 0–4 mm)8 at 1-hour post-dose (Figure 1). In the phase III studies, a low number of ISR/ISP events were observed, which decreased during the course of study. Detailed results are provided in Table 1. No ISR/ISP led to treatment or study discontinuation in any study.

Conclusion:

The proportion of HV and pts experiencing ISR and ISP after administration of SDZ-ADL was low, with no events leading to treatment or study discontinuation. These results call into question the clinical impact of citrate and its concentration in ADL formulations on the incidence and intensity of ISP.

References:

[1]Nash et al. Rheumatol Ther. 2016;3:257–70.

[2]NHS. Regional medicines optimisation committee briefing, best value biologicals: adalimumab update 6. July 2019. https://www.sps.nhs.uk/wp-content/uploads/2019/07/Adalimumab-RMOC-Briefing-6.pdf.

[3]https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/761071lbl.pdf.

[4]Blauvelt A, et al. Br J Dermatol. 2018;179:623–31.

[5]Wiland P, et al. BioDrugs 2020;34:809–23.

[6]Richter OV, et al. Expert Opin Biol Ther. 2019;19:1057–64.

[7]Richter OV, et al. Expert Opin Biol Ther. 2019;19:1075–83.

[8]Hawker GA, et al. Arthritis Care Res. 2011;63:240–52.

Figure 1.

Proportion of HV with ISP in phase I PK studies

Table 1.

ISP and ISR results from phase I PK and phase III confirmatory studies

Phase I PK studiesStudy101(N=73)102(N=108)103(N=178)104(N=107)Pooled studies (N=466)VAS scores (mm) at 1-hour post-doseMean (SD)0.89 (2.07)0.07 (0.52)1.03 (1.71)1.03 (2.49)0.79 (1.84)Median00100ISR scores at 1-hour post-dose, n (%)None73 (100)106 (98.2)178 (100)99 (92.5)456 (97.9)Mild0 (0)1 (0.9)0 (0)8 (7.5)9 (1.9)Moderate0 (0)1 (0.9)0 (0)0 (0)1 (0.2)Phase III confirmatory studiesADACCESS5* (PsO and PsA pts)ADMYRA6* (RA pts)W0–17 (N=231)W0–51 (N=168; including pts re-randomised to continue SDZ-ADL after W17)W0–24 (N=177)W0–48 (N=177; all pts continued SDZ-ADL after W24)DosageInduction 80 mg W0, then 40 mg EoW s.c.40 mg EoW s.c.40 mg EoW s.c.40 mg EoW s.c.Study duration, W17512448AEs - ISR, n (%), events15 (6.5), 349 (5.4), 267 (4.0), 117 (4.0), 12Mild14 (6.1), 309 (5.4), 267 (4.0), 117 (4.0), 12Moderate1 (0.4), 4000AEs - ISP (reported as ISR), n (%)3 (1.3)1 (0.6)2 (1.1)2 (1.1)

*ADACCESS and ADMYRA were switch studies, therefore, only pts exposed to SDZ-ADL throughout the study period are included here. EoW, every other week, N, number of HV or pts

Disclosure of Interests:

Piotr Wiland Speakers bureau: Celltrion, Celgene, Eli Lilly, Novartis, Pfizer, Sandoz, Sanofi-Aventis, Consultant of: Celltrion, Celgene, Eli Lilly, Novartis, Pfizer, Sandoz, Sanofi-Aventis, Andrew Blauvelt Speakers bureau: AbbVie, Almirall, Arena, Athenex, Boehringer Ingelheim, Bristol-Myers Squibb, Dermavant, Eli Lilly and Company, Evommune, Forte, Galderma, Incyte, Janssen, Leo, Novartis, Pfizer, Rapt, Regeneron, Sandoz, Sanofi Genzyme, Sun Pharma, and UCB Pharma., Consultant of: AbbVie, Almirall, Arena, Athenex, Boehringer Ingelheim, Bristol-Myers Squibb, Dermavant, Eli Lilly and Company, Evommune, Forte, Galderma, Incyte, Janssen, Leo, Novartis, Pfizer, Rapt, Regeneron, Sandoz, Sanofi Genzyme, Sun Pharma, and UCB Pharma., Lena Lemke Employee of: Hexal AG, Oliver von Richter Employee of: Hexal AG, Alison Balfour Employee of: Hexal AG, Fabricio Furlan Employee of: Hexal AG, Norman Gaylis: None declared

Multicentric Retrospective Evaluation of Five Classic Infantile Pompe Disease Subjects Under Enzyme Replacement Therapy With Early Infratentorial Involvement

White matter (WM) abnormalities and ventricular enlargement in brain MRI are well-known features in infantile-onset Pompe disease (IOPD) in the era of enzyme replacement therapy (ERT). In this multicentric observational retrospective study, we report a small cohort of IOPD subjects under ERT treatment (n = 5, median age at MRI = 7.4 years, median period of treatment = 85 months) that showed the classic features of extensive supratentorial WM abnormalities but also unusual findings such as early infratentorial WM abnormalities and late supratentorial U-fiber involvement. Given the recent implementation of ERT and the rarity of the disease, a complete spectrum of presentation and understanding of progressive pathology in the brain of IOPD subjects in treatment remains underacknowledged. The availability of long-term follow-up of IOPD subjects under ERT treatment allows a better insight into the evolution of brain abnormalities in such disease.

AB0299 REAL-WORLD ASSESSMENT OF GP2015 (ETANERCEPT BIOSIMILAR, SDZ-ETN): AN INTERIM ANALYSIS OF DATA FROM THE SELF-INJECTION ASSESSMENT QUESTIONNAIRE IN PATIENTS WITH RHEUMATOID ARTHRITIS IN THE COMPACT STUDY

Background:

COMPACT is a non-interventional study to collect real-world evidence in European countries and Canada on effectiveness, safety and quality of life in rheumatoid arthritis (RA), ankylosing spondylitis or psoriatic arthritis patients (pts) treated with SDZ-ETN (GP2015), an approved etanercept biosimilar. The first effectiveness and safety data from the study have been reported earlier1.

Objectives:

This interim analysis assessed patient usage behaviour and feelings of self-administered injection in general and with the auto-injector device using the Self-Injection Assessment Questionnaire (SIAQ) at Week 12 in pts with RA.

Methods:

Pts aged ≥18 years for whom treatment with SDZ ETN were initiated are being enrolled. The SIAQ, a patient questionnaire validated for pts with RA, was developed to assess overall pt experience with subcutaneous self-injection2. It assesses the perceived self-confidence on self-injection, potential barriers, as well as satisfaction with self-injection via device before the first self-injection (PRE module) and after dosing (POST module). The POST module used in COMPACT includes 21 items grouped into six hypothetical domains: “feelings about injection”,“self-image”, “self-confidence”, “injection-site reactions”, “ease of use of self-injection device (SD), and “satisfaction with self-injection”. Descriptive statistics were used to summarise SIAQ POST module data. The results for “ease of use of SD” domain are reported here. The “ease of use of SD” was rated by pts on a 6-point scale: 1 (very difficult) to 6 (very easy).

Results:

Of the 430 pts recruited, pts with RA represented the largest group (59.5%, n=256). Majority of pts with RA (77.7%) had comorbidities. Of the 256 pts with RA, 102 (40%) pts who used SD responded to the questionnaire. Majority of the pts found usage of the SD easy or very easy, for each of the domains assessed (Table). 49 % and 14% of the patients were “comfortable” and “very comfortable”, respectively using the SD. A majority of patients reported to be bothered by pain at the injection site “not at all” or only “a little” (69.6%), and to be bothered by redness “not at all” or only “a little” (89.2%), respectively.

Table.

Overall patient experience with usability of self-injection device at Week 12 (RA population)

Domain: Ease of use of self-injection deviceQuestionsCategory, %Very easyEasySome what easySomewhat difficultDifficultVery difficultN/ARemoval of Cap36.334.316.74.93.92.02.0To depress the device34.342.213.72.92.02.92.0To administer without any help42.235.310.82.02.05.92.0Use of self-injection device38.237.311.83.92.93.92.0

Conclusion:

The interim analysis results, although descriptive, show a clear trend for ease of use and good satisfaction with SDZ-ETN SD in pts with RA.

References:

[1]Schmalzing M, et al.Arthritis Rheumatol. 2019;71 (suppl 10).

[2]Keininger D, et al.Health Qual Life Outcomes. 2011,13;9:2.

Disclosure of Interests:

Herbert Kellner: None declared, Ayman Askari Speakers bureau: Eli Lilly, Pfizer, Thomas Kupka: None declared, Hilke Friccius-Quecke Employee of: Sandoz Hexal AG, Fabricio Furlan Employee of: Sandoz Hexal AG, Sohaib HACHAICHI Employee of: Sandoz Hexal AG, Marc Schmalzing Consultant of: Paid consultant for Hexal AG

A new case report of severe mucopolysaccharidosis type VII: diagnosis, treatment with haematopoietic cell transplantation and prenatal diagnosis in a second pregnancy

A new patient with severe mucopolysaccharidosis (MPS) type VII is reported. Non-immune hydrops fetalis (NIHF) was diagnosed during pregnancy. At birth, he showed generalized hydrops and dysmorphic features typical of MPS. Many diagnoses were excluded before reaching the diagnosis of MPS VII at 8 months of life. During the first year of life he had frequent respiratory infections associated with restrictive and obstructive bronchopneumopathy and underwent three surgical interventions: decompression of the spinal cord at the craniocervical junction, bilateral inguinal hernia, and bilateral clubfoot. At 14 months of life he underwent successful haematopoietic cell transplantation (HCT). During the following 10 months, his bronchopneumopathy progressively worsened, needing chronic pharmacological treatment and O₂ administration. The patient died of respiratory insufficiency during a respiratory syncytial virus infection at 25 months of age. Molecular analysis showed the homozygous variant c.1617C > T, leading to the synonymous mutation p.Ser539=. This caused aberrant splicing with partial skipping of exon 10 (r.1616_1653del38) and complete skipping of exon 9 (r.1392_1476del85; r.1616_1653del38). No transcript of normal size was evident. The parents were both confirmed to be carriers. In a subsequent pregnancy, a prenatal diagnosis showed an affected fetus. Ultrasound examination before abortion showed NIHF. The skin and placenta examination by electron microscopy showed foamy intracytoplasmic vacuoles with a weakly electron-dense substrate. MPS VII is a very rare disease but it is possible that some cases go undiagnosed for several reasons, including that MPS VII, and other lysosomal storage diseases, are not included in the work-up for NIHF in many institutions, and the presence of anasarca at birth may be confounding for the recognition of the typical facial characteristics of the disease. This is the eighth patient affected by MPS VII who has undergone HCT. It is not possible to draw conclusions about the efficacy of HCT in MPS VII. Treatment with enzyme replacement is now available and will probably be beneficial for the patients who have a milder form with no or little cognitive involvement. Increased awareness among clinicians is needed for prompt diagnosis and to offer the correct treatment as early as possible.

Detecção molecular de Neospora caninum em macaco-da-noite (Aotus azarae) de vida livre no estado do Mato Grosso: relato de caso

RESUMO Estudos indicam, por meio de infecção experimental, que primatas não humanos são susceptíveis à infecção por Neospora caninum. Relata-se um caso de um macaco-da-noite (Aotus azarae infulatus), que apresentou sinais inespecíficos e não respondeu à terapêutica clínica de suporte, evoluindo a óbito, encaminhado em seguida para exame anatomopatológico. Amostras de tecidos foram coletadas e processadas rotineiramente para confecção de lâminas histológicas. Microscopicamente, a principal lesão foi observada no coração e consistia em miocardite necrótica multifocal por protozoário, com a presença de estruturas compatíveis com o estágio de taquizoítos de protozoários dos gêneros Neospora sp. ou Toxoplasma sp. No sistema nervoso central, predominantemente no tronco encefálico, havia estruturas semelhantes às descritas no coração. Os resultados da reação em cadeia pela polimerase (PCR) foram positivos para N. caninum e negativos para Toxoplasma gondii, usando DNA extraído do sangue e dos tecidos. Este relato de caso fornece evidências histológicas e moleculares de que o primata em questão foi susceptível a uma infecção natural, porém estudos devem ser realizados para investigar o real papel dos primatas no ciclo de vida de N. caninum.

High level of oxysterols in neonatal cholestasis: a pitfall in analysis of biochemical markers for Niemann-Pick type C disease

Niemann-Pick disease type C (NPC) is a rare lipid storage disorder characterized by progressive neurological deterioration. Diagnosing NPC is challenging as clinical signs and symptoms are variable and non-specific. Two oxysterols, cholestane-3β,5α,6β-triol (triol) and 7-ketocholesterol (7KC), have been proposed as biomarkers for aiding diagnosis of NPC. This study evaluated the use of triol and 7KC as biomarkers in cholestatic neonates with suspected NPC.

Plasma triol and 7KC were analysed as dimethylglycine esters using an liquid chromatography – tandem mass spectrometry (LC-MS/MS) assay in selected neonates with severe cholestasis and suspected NPC (n=7), adults with cholestasis (n=15), patients with confirmed NPC (positive controls; n=11 [one child and 10 adults]), healthy subjects (negative controls; n=40 [20 children and 20 adults]), and cholestatic adults (comparative reference; n=15). The LC-MS/MS method was subjected to a number of tests for accuracy and consistency.

Triol and 7KC levels were substantially and significantly increased in NPC positive patients compared with healthy controls (p<0.001). However, positive results (markedly increased levels of both oxysterols) were identified in 6/7 (86%) neonates with cholestasis. Genetic testing confirmed NPC only in one neonate who had increased triol and 7KC, and increased oxysterol levels among neonates with no identified NPC gene mutations were considered likely due to biliary atresia (BA).

While the potential of oxysterols as NPC biomarkers has been well evaluated in older patient populations (without cholestasis), our data suggest that cholestasis might represent a pitfall in oxysterol measurements intended to aid diagnosis of NPC in affected patients.

The phenotypic spectrum of organic acidurias and urea cycle disorders. Part 1: the initial presentation

BACKGROUND

The clinical presentation of patients with organic acidurias (OAD) and urea cycle disorders (UCD) is variable; symptoms are often non-specific.

AIMS/METHODS

To improve the knowledge about OAD and UCD the E-IMD consortium established a web-based patient registry.

RESULTS

We registered 795 patients with OAD (n = 452) and UCD (n = 343), with ornithine transcarbamylase (OTC) deficiency (n = 196), glutaric aciduria type 1 (GA1; n = 150) and methylmalonic aciduria (MMA; n = 149) being the most frequent diseases. Overall, 548 patients (69 %) were symptomatic. The majority of them (n = 463) presented with acute metabolic crisis during (n = 220) or after the newborn period (n = 243) frequently demonstrating impaired consciousness, vomiting and/or muscular hypotonia. Neonatal onset of symptoms was most frequent in argininosuccinic synthetase and lyase deficiency and carbamylphosphate 1 synthetase deficiency, unexpectedly low in male OTC deficiency, and least frequently in GA1 and female OTC deficiency. For patients with MMA, propionic aciduria (PA) and OTC deficiency (male and female), hyperammonemia was more severe in metabolic crises during than after the newborn period, whereas metabolic acidosis tended to be more severe in MMA and PA patients with late onset of symptoms. Symptomatic patients without metabolic crises (n = 94) often presented with a movement disorder, mental retardation, epilepsy and psychiatric disorders (the latter in UCD only).

CONCLUSIONS

The initial presentation varies widely in OAD and UCD patients. This is a challenge for rapid diagnosis and early start of treatment. Patients with a sepsis-like neonatal crisis and those with late-onset of symptoms are both at risk of delayed or missed diagnosis.

The phenotypic spectrum of organic acidurias and urea cycle disorders. Part 2: the evolving clinical phenotype

BACKGROUND

The disease course and long-term outcome of patients with organic acidurias (OAD) and urea cycle disorders (UCD) are incompletely understood.

AIMS

To evaluate the complex clinical phenotype of OAD and UCD patients at different ages.

RESULTS

Acquired microcephaly and movement disorders were common in OAD and UCD highlighting that the brain is the major organ involved in these diseases. Cardiomyopathy [methylmalonic (MMA) and propionic aciduria (PA)], prolonged QTc interval (PA), optic nerve atrophy [MMA, isovaleric aciduria (IVA)], pancytopenia (PA), and macrocephaly [glutaric aciduria type 1 (GA1)] were exclusively found in OAD patients, whereas hepatic involvement was more frequent in UCD patients, in particular in argininosuccinate lyase (ASL) deficiency. Chronic renal failure was often found in MMA, with highest frequency in mut(0) patients. Unexpectedly, chronic renal failure was also observed in adolescent and adult patients with GA1 and ASL deficiency. It had a similar frequency in patients with or without a movement disorder suggesting different pathophysiology. Thirteen patients (classic OAD: 3, UCD: 10) died during the study interval, ten of them during the initial metabolic crisis in the newborn period. Male patients with late-onset ornithine transcarbamylase deficiency were presumably overrepresented in the study population.

CONCLUSIONS

Neurologic impairment is common in OAD and UCD, whereas the involvement of other organs (heart, liver, kidneys, eyes) follows a disease-specific pattern. The identification of unexpected chronic renal failure in GA1 and ASL deficiency emphasizes the importance of a systematic follow-up in patients with rare diseases.

Homozygous MTTP and APOB mutations may lead to hepatic steatosis and fibrosis despite metabolic differences in congenital hypocholesterolemia

BACKGROUND & AIMS

Non-alcoholic steatohepatitis leading to fibrosis occurs in patients with abetalipoproteinemia (ABL) and homozygous or compound heterozygous familial hypobetalipoproteinemia (Ho-FHBL). We wanted to establish if liver alterations were more frequent in one of both diseases and were influenced by comorbidities.

METHODS

We report genetic, clinical, histological and biological characteristics of new cases of ABL (n =7) and Ho-FHBL (n = 7), and compare them with all published ABL (51) and Ho-FHBL (22) probands.

RESULTS

ABL patients, diagnosed during infancy, presented mainly with diarrhea, neurological and ophthalmological impairments and remained lean, whereas Ho-FHBL were diagnosed later, with milder symptoms often becoming overweight in adulthood. Despite subtle differences in lipid phenotype, liver steatosis was observed in both groups with a high prevalence of severe fibrosis (5/27 for Ho-FHBL vs. 4/58 for ABL (n.s.)). Serum triglycerides concentration was higher in Ho-FHBL whereas total and HDL-cholesterol were similar in both groups. In Ho-FHBL liver alterations were found to be independent from the apoB truncation size and apoB concentrations.

CONCLUSIONS

Our findings provide evidence for major liver abnormalities in both diseases. While ABL and Ho-FHBL patients have subtle differences in lipid phenotype, carriers of APOB mutations are more frequently obese. These results raise the question of a complex causal link between apoB metabolism and obesity. They suggest that the genetic defect in VLDL assembly is critical for the occurrence of liver steatosis leading to fibrosis and shows that obesity and insulin resistance might contribute by increasing lipogenesis.

Epilepsia partialis continua and generalized nonconvulsive status epilepticus during the course of argininemia: a report on two cases

Argininemia is a rare inherited disorder of the urea cycle because of a deficiency of the enzyme arginase I causing an increase of arginine and guanidino compounds in the blood, urine, and cerebrospinal fluid. The clinical picture is characterized by a mild cognitive dysfunction, progressive asymmetrical paraparesis, and seizures. Here, we describe two cases of argininemia where either epilepsia partialis continua (EPC) or nonconvulsive status epilepticus (NCSE) were the presenting manifestations of epilepsy. This is the first report of EPC in an urea cycle disorder. In both the cases, status epilepticus resolved with anticonvulsive drugs. EPC was successfully treated with levetiracetam, and NCSE with valproic acid. No side effects were observed. Because hyperammonemia and NCSE may have the same features of stupor, a neurophysiological approach might prove useful in differentiating these two conditions. Overall, our results strongly indicate that a correct NCSE diagnosis is mandatory to prevent further deterioration in these patients.

Intrafamilial phenotypic variability in four families with Anderson-Fabry disease

We analysed the clinical history of 16 hemizygous males affected by Anderson-Fabry Disease, from four families, to verify their intrafamilial phenotypic variability. Seven male patients, ranging from 26 to 61 years of age, died, whereas nine (age range 23-55) are alive. Eleven patients have undergone enzyme replacement therapy (ERT) for a period of 5-10 years. We have found a wide range of intrafamilial phenotypic variability in these families, both in terms of target-organs and severity of the disease. Overall, our findings confirm previous data from the literature showing a high degree of intrafamilial phenotypic variability in patients carrying the same mutation. Furthermore, our results underscore the difficulty in giving accurate prognostic information to patients during genetic counselling, both in terms of rate of disease progression and involvement of different organs, when such prognosis is solely based on the patient's family history.

Mutations in FBXL4, encoding a mitochondrial protein, cause early-onset mitochondrial encephalomyopathy

Whole-exome sequencing and autozygosity mapping studies, independently performed in subjects with defective combined mitochondrial OXPHOS-enzyme deficiencies, identified a total of nine disease-segregating FBXL4 mutations in seven unrelated mitochondrial disease families, composed of six singletons and three siblings. All subjects manifested early-onset lactic acidemia, hypotonia, and developmental delay caused by severe encephalomyopathy consistently associated with progressive cerebral atrophy and variable involvement of the white matter, deep gray nuclei, and brainstem structures. A wide range of other multisystem features were variably seen, including dysmorphism, skeletal abnormalities, poor growth, gastrointestinal dysmotility, renal tubular acidosis, seizures, and episodic metabolic failure. Mitochondrial respiratory chain deficiency was present in muscle or fibroblasts of all tested individuals, together with markedly reduced oxygen consumption rate and hyperfragmentation of the mitochondrial network in cultured cells. In muscle and fibroblasts from several subjects, substantially decreased mtDNA content was observed. FBXL4 is a member of the F-box family of proteins, some of which are involved in phosphorylation-dependent ubiquitination and/or G protein receptor coupling. We also demonstrate that FBXL4 is targeted to mitochondria and localizes in the intermembrane space, where it participates in an approximately 400 kDa protein complex. These data strongly support a role for FBXL4 in controlling bioenergetic homeostasis and mtDNA maintenance. FBXL4 mutations are a recurrent cause of mitochondrial encephalomyopathy onset in early infancy.

Severe Neonatal Metabolic Decompensation in Methylmalonic Acidemia Caused by CblD Defect

CblD disorder is an autosomal recessive, rare, heterogeneous disease with variable clinical presentations, depending on the nature and location of the MMADHC gene mutations. Mutations in MMADHC lead to three distinct phenotypes: cblD-MMA, cblD-HC, and cblD-MMA/HC. To date, 18 cblD patients have been reported. Six of them were affected by cblD-MMA, but only three had a known clinical history. One of these patients presented with a metabolic decompensation at 11 months; the second one, born prematurely, was diagnosed with cblD after being treated for intracranial hemorrhage, respiratory distress syndrome, necrotizing enterocolitis, and convulsions at birth; the third one was diagnosed at 5 years of age.Here we present a case of a cblD-MMA patient who had an acute neonatal onset with severe hyperammonemia requiring hemodiafiltration. To the best of our knowledge, this is the first cblD-MMA patient who presented acutely in the newborn period. He has developed well upon treatment with B12, carnitine, and hypoproteic diet. At present time, at the age of 7, he shows normal growth and cognitive development. Thus, it is likely that the aggressive treatment of this child with hemodiafiltration might have prevented him from long-term neurological sequelae. Overall, this case shows that even severe, neonatal-onset patients may display a vitamin B12-responsive MMA. Furthermore, it suggests that an early treatment with vitamins might be beneficial for patients presenting with neonatal-onset hyperammonemia regardless of the suspected disease and before receiving the biochemical diagnosis.

Congenital hyperinsulinism: clinical and molecular analysis of a large Italian cohort

Congenital hyperinsulinism (CHI) is a genetic disorder characterized by profound hypoglycemia related to an inappropriate insulin secretion. It is a heterogeneous disease classified into two major subgroups: "channelopathies" due to defects in ATP-sensitive potassium channel, encoded by ABCC8 and KCNJ11 genes, and "metabolopathies" caused by mutation of several genes (GLUD1, GCK, HADH, SLC16A1, HNF4A and HNF1A) and involved in different metabolic pathways. To elucidate the genetic etiology of CHI in the Italian population, we conducted an extensive sequencing analysis of the CHI-related genes in a large cohort of 36 patients: Twenty-nine suffering from classic hyperinsulinism (HI) and seven from hyperinsulinism-hyperammonemia (HI/HA). Seventeen mutations have been found in fifteen HI patients and five mutations in five HI/HA patients. Our data confirm the major role of ATP-sensitive potassium channel in the pathogenesis of Italian cases (~70%) while the remaining percentage should be attributed to other. A better knowledge of molecular basis of CHI would lead to improve strategies for genetic screening and prenatal diagnosis. Moreover, genetic analysis might also help to distinguish the two histopathological forms of CHI, which would lead to a clear improvement in the treatment and in genetic counseling.

Purity and stability of online-prepared hemodiafiltration fluid after storage

BACKGROUND/AIMS

Previous studies have suggested that online hemodiafiltration (OL-HDF) fluid can be used as dialysate for continuous renal replacement therapies, and thus HDF costs can be reduced. The aims of this study were to determine the purity of OL-HDF fluid and to verify the stability of the electrolyte composition and acid-base balance during its storage.

METHODS

OL-HDF fluid was collected in 70 individual bags and stored for up to 7 days. The following tests were performed daily in 10 bags: natural visible precipitation (macrocrystallization), sample collection for chemical analysis and fluid culture, limulus amebocyte lysate endotoxin test, standard culture of NALGENE® filters after passing of the fluid, and molecular analysis of bacterial DNA.

RESULTS

The values of pH and pCO(2) showed a significant change starting at 24 h (p < 0.001); after 72 h, their values were beyond the measurable range. Coefficient of variation for pCO(2) was as high as 25.7%. Electrolyte composition (Na(+), K(+), Cl(-), Ca(2+) and glucose) showed a statistically significant difference over time (p < 0.05); however, their coefficients of variation were low (1.7, 1.4, 0.6, 2.3 and 0.9%, respectively), which might not be considered clinically significant. Negative results were obtained at all points by fluid and filter cultures, endotoxin test and molecular analysis. No macrocrystallization was observed at any time point.

CONCLUSIONS

We demonstrate the microbiological purity of OL-HDF fluid stored for up to 7 days. The electrolyte composition was stable, except for a relevant change in pCO(2) and consequently in pH (first noted at 24 h), emphasizing the need to reassess the acid-base balance in multilayer plastic bags in future studies.

Epilepsy and argininosuccinic aciduria

BACKGROUND

We have reviewed the occurrence of epilepsy in our patients with argininosuccinic aciduria (ASA) (OMIM 207900) and the possible relationship of late epilepsy to symptomatic seizures in the neonatal period, hyperammonaemia and treatments.

METHODS

We retrospectively analysed 11 ASA patients (8 neonatal onset and 3 late onset), 6 of whom had developed epilepsy.

RESULTS

Epilepsy in our sample was frequent (55 %). It developed after a seizure-free period from the onset of the metabolic disease and seizures were responsive to treatment in all cases. Arginine plasma levels were kept in the same range for the 2 groups of patients with and without epilepsy.

CONCLUSIONS

Although epilepsy is reported to be common among patients with ASA, very few long-term follow-up studies are available. The pathophysiological mechanism of epileptogenesis remains unclear. Neither hyperammonaemia nor acute symptomatic seizures at birth seem to be predictive of late epilepsy. Excessive arginine dosages as a cause of epilepsy could be reasonably excluded since our 3 late onset patients developed epilepsy before the diagnosis of ASA, at a time when they were likely to be arginine deficient. Arginine deficiency may not be excluded as cause of epilepsy, but further studies are needed to define its role.

Brain and spine MRI features of Hunter disease: frequency, natural evolution and response to therapy

BACKGROUND

Hunter disease is a rare X-linked mucopolysaccharidosis. Despite frequent neurological involvement, characterizing the severe phenotype, neuroimaging studies are scarce.

OBJECTIVES

To determine frequency and severity of neuroradiological mucopolysaccharidosis-related features; to correlate them with clinical phenotype; to evaluate their natural evolution and the impact of intravenous enzymatic replacement therapy (ERT).

METHODS

Sixty nine brain MRI examinations of 36 Italian patients (mean-age 10.4 years; age-range 2.2-30.8; severe phenotype in 22 patients) were evaluated. Twenty patients had multiple MRIs (median follow-up 3.1 years, range 1-16.9): among them 15 had MRIs before and after ERT, six had repeated MRIs without being on ERT and five while on ERT. Perivascular, subarachnoid and ventricle space enlargement, white matter abnormality (WMA) burden, pituitary sella/skull/posterior fossa abnormalities, periodontoid thickening, spinal stenosis, dens hypoplasia, myelopathy, vertebral and intervertebral disc abnormalities were graded by means of dedicated scales.

RESULTS

Perivascular spaces enlargement (89%), WMAs (97%), subarachnoid space enlargement (83%), IIIrd-ventricle dilatation (100%), pituitary sella abnormalities (80%), cranial hyperostosis (19%), craniosynostosis (19%), enlarged cisterna magna (39%), dens hypoplasia (66%), periodontoid thickening (94%), spinal stenosis (46%), platyspondylia (84%) and disc abnormalities (79%) were frequently detected. WMAs, IIIrd-ventricle dilatation and hyperostosis correlated with the severe phenotype (p < 0.05). Subarachnoid spaces and ventricle enlargement, WMAs and spinal stenosis progressed despite ERT, while other MR features showed minimal or no changes.

CONCLUSIONS

The spectrum of brain and spine MRI abnormalities in Hunter disease is extremely wide and requires a thorough evaluation. WMAs, atrophy/communicating hydrocephalus and spinal stenosis progress over time and might represent possible disease severity markers for new treatment efficacy assessment.

IDUA mutational profiling of a cohort of 102 European patients with mucopolysaccharidosis type I: identification and characterization of 35 novel α-L-iduronidase (IDUA) alleles

Mutational analysis of the IDUA gene was performed in a cohort of 102 European patients with mucopolysaccharidosis type I. A total of 54 distinct mutant IDUA alleles were identified, 34 of which were novel including 12 missense mutations, 2 nonsense mutations, 12 splicing mutations, 5 micro-deletions, 1 micro-duplication 1 translational initiation site mutation, and 1 'no-stop' change (p.X654RextX62). Evidence for the pathological significance of all novel mutations identified was sought by means of a range of methodological approaches, including the assessment of evolutionary conservation, RT-PCR/in vitro splicing analysis, MutPred analysis and visual inspection of the 3D-model of the IDUA protein. Taken together, these data not only demonstrate the remarkable mutational heterogeneity characterizing type 1 mucopolysaccharidosis but also illustrate our increasing ability to make deductions pertaining to the genotype-phenotype relationship in disorders manifesting a high degree of allelic heterogeneity.

Intravenous enzyme replacement therapy: hospital vs home

Two surveys were carried out to establish the status of enzyme replacement therapy (ERT) for lysosomal storage diseases in Italy. The first was a national survey covering the regional reference centres (RRCs) for these diseases; replies disclosed that 57.7% of patients are on ERT, administered almost exclusively in hospital settings (local hospital 60.7%, RRC 34.8%, home 2.6%); Italian health service procedures do not support ERT at home. The second survey was a regional survey in Lombardy, involving 48 patients (six of whom were on ERT at home). According to 40% of the patients, hospital-based ERT is disruptive, causing loss of days at school/work, stress and family issues. The patients on home therapy did not have these problems. However, 93% of patients receiving ERT in hospital perceived the advantages of greater safety, closer monitoring and more support from health professionals and experts. A total of 55% were willing to receive ERT at home, but 33% were against it. This may be the result of a lack of experience with ERT at home in Italy, or because of different opinions between family members and physicians. As international experience shows that ERT at home saves healthcare resources and improves quality of life, the issue should be raised with Italian healthcare policy makers, who should ensure nursing support for home-based ERT.

Glucose metabolism and diet-based prevention of liver dysfunction in MPV17 mutant patients

BACKGROUND/AIMS

To describe in detail the specific clinical and biological characteristics of three patients with MPV17 gene mutations, a rare hepatocerebral mitochondrial DNA depletion syndrome (MDS) and the positive effects of a novel dietetic treatment based on avoidance of fasting.

METHODS

We describe the case histories of three members of the same family with MPV17 mutations.

RESULTS

Two patients had a very severe and progressive liver disease: 1 died in the first year of life and the other underwent liver transplantation. The third patient, now 13 years of age, had a milder form of liver disease and developed progressive ataxia. Psychomotor involvement at onset of disease was mild or absent. No patient had severe hyperlactataemia. In vivo functional studies on two patients showed no hyperlactataemia even after intravenous and oral glucose loading, regular fasting hypoglycemia 3-4h after meals and no response to glucagon. Liver function tests improved when patients received continuous iv glucose infusion or were regularly fed every 3h.

CONCLUSIONS

These clinical and biochemical features allow us to differentiate patients with MPV17 mutations from other liver MDS and suggest that regular glucose intake at short intervals may be beneficial in slowing the progression of the disease.

Staphylococcus caprae meningitis following intraspinal device infection

A case is reported of Staphylococcus caprae meningitis due to infection of an intraspinal analgesia pump. The subclinical and pauci-symptomatic clinical course of the infection strongly suggested a chronic device contamination.

Enzyme replacement therapy with agalsidase alfa in a cohort of Italian patients with Anderson-Fabry disease: testing the effects with the Mainz Severity Score Index

Anderson-Fabry disease (AFD) is a rare X-linked disorder caused by lysosomal storage of several glycosphingolipids, affecting virtually all organs and systems. Enzyme replacement therapy (ERT) for AFD has been available since 2001. Due to the highly variable nature of clinical manifestations in patients with AFD, it is very difficult to assess disease progression and the effects of therapy. We used the Mainz Severity Score Index (MSSI) as a measure of disease severity to study the effects of ERT in a population of 30 patients treated with agalsidase alfa for a median of 2.9 years (range, 1.0-6.2 years). Our data show that the MSSI captures the correlation between disease severity and both gender and age (1 - males performing worse than females at baseline and 2 - severity of diseases progresses with age in both sex). Furthermore, after at least 1 year of ERT, total MSSI scores were significantly lower than those at baseline (p < 0.001), suggesting a marked clinical improvement under ERT. In conclusion, the MSSI is a sensitive and useful tool for monitoring disease progression and assessing the effects of ERT in a population of patients from different treatment centres.

Bilateral nuclear cataracts as the first neonatal sign of Fanconi-Bickel syndrome

A patient with early bilateral nuclear cataracts and subsequent diagnosis of Fanconi-Bickel syndrome is described. Despite impaired galactose and glucose metabolism, cataracts have been reported in only few cases with this disorder. We conclude that Fanconi-Bickel syndrome should be considered in the differential diagnosis of neonatal cataracts. The pathogenesis of this complication has not been fully elucidated.

Characterisation of carotid atherosclerotic plaque: comparison between magnetic resonance imaging and histology

PURPOSE

The aim of this study was to identify and characterise by magnetic resonance imaging (MRI) carotid plaque constituents such as lipid-rich necrotic core, intraplaque haemorrhage and calcification in patients treated with carotid endarterectomy (CEA) using histological evaluation as the reference standard.

MATERIALS AND METHODS

Nineteen patients (13 men and six women) scheduled for CEA between March and August 2004 were imaged on a 1.5-T scanner (Magnetom Symphony, Siemens, Erlangen, Germany). The protocol included four types of sequences [T1, T2, proton density (PD) and three-dimensional time of flight (3D-TOF)]. Images were reviewed for integrity of the fibrous cap, presence of lipid-rich necrotic core, intraplaque haemorrhage and calcification. Signal intensity was assessed relative to the adjacent sternocleidomastoid muscle. Four cross-sections for each lesion were compared with the corresponding histological specimens and independently reviewed by two radiologists and one pathologist.

RESULTS

MRI detected lipid-rich necrotic core with a sensitivity and specificity of 91.6% and 95.0%, respectively, whereas it defined intraplaque haemorrhage alone with a sensitivity and specificity of 91.6% and 100%, respectively. Calcification was recognised with a sensitivity and specificity of 80% and 93.7%, respectively.

CONCLUSIONS

MRI is able to identify signs of carotid plaque instability with a high sensitivity and specificity. Therefore, it may be useful in evaluating and guiding the treatment of haemodynamically nonsignificant stenoses with a potential embolic risk and, in the future, to assess coronary plaque.

A direct link between expression of urokinase plasminogen activator receptor, growth rate and oncogenic transformation in mouse embryonic fibroblasts

In addition to its role in invasion and metastasis of several tumors, the multifunctional urokinase receptor uPAR (urokinase plasminogen activator receptor) is directly involved in the growth of several cancer cells in vitro and in vivo. We have compared growth rate and oncogenic transformation in wild-type (wt) or uPAR-/- mouse embryonic fibroblasts (MEFs). Surprisingly, uPAR-/- MEFs grew faster than wt MEFs. This agreed with elevated levels of cell cycle mediators like extracellular signal-regulated protein kinase, p38, AP1 and Cyclin D1. Infection with a uPAR retrovirus reverted the effect, decreasing the growth rate. When MEFs were transformed with H-Ras(V12) and E1A oncogenes, the efficiency of transformation in uPAR-/- MEFs was higher than in wt. UPAR-/- MEFs grew faster at low serum, produced more colonies in agar and produced tumors in vivo in nude mice with a lower latency period. The properties of the heterozygous uPAR+/- MEFs were always intermediate. We conclude therefore that in MEFs uPAR concentration controls cell proliferation and the transforming activity of some oncogenes.

Multiple cryptic splice sites can be activated by IDS point mutations generating misspliced transcripts

Mutations in the gene encoding the enzyme iduronate-2-sulfatase (IDS) were reported as the cause of the X-linked recessive lysosomal disease, mucopolysaccharidosis II (MPS II). Amongst the different mutations, it emerges that nearly 10% are nucleotide substitutions causing splicing mutations. We now report the molecular characterisation of three MPS II patients with multiple aberrant transcripts due to three different point mutations. The c.418+1G>C that occurred in the invariant splice-site motif, produced only aberrantly spliced transcripts. Whilst the mutations affecting variant motifs (c.419G>T) or coding regions (c.245C>T) led to aberrantly spliced transcripts in addition to correctly spliced transcripts with the respective predicted missense mutation, p.G140V or p.A82V. A combination of experimental tests and computational approaches were used to understand the molecular basis underlying the altered transcription patterns. In addition, by using real-time reverse transcriptase polymerase chain reaction, the reduction of mRNA amount in two patients observed was likely due to nonsense-mediated mRNA decay pathway. Overall, our results further emphasised the importance of cloning and sequencing independent transcripts to reveal less abundant, aberrant products, which often could not be detected by direct sequencing. Moreover, the different splicing patterns observed in the three patients as a consequence of point mutations show how sensitive the balance is between constitutive and cryptic splice sites in the IDS gene. The generation of such diverse transcripts, together with their level of expression, could contribute to the profound phenotypic variability reported in MPS II.

DIURNAL VARIATION IN CLINICALLY SIGNIFICANT DIABETIC MACULAR EDEMA MEASURED BY THE STRATUS OCT

PURPOSE

To investigate diurnal variation in clinically significant macular edema (CSME) using the Stratus OCT (Carl Zeiss Meditec).

METHODS

Fifteen eyes of 15 diabetic patients with CSME and 10 healthy subjects (controls) underwent four optical coherence tomography (OCT) measurements of macular thickness with the fast macular thickness mapping protocol of the Stratus OCT at 9 am, 12 pm, 3 pm, and 6 pm. Early Treatment Diabetic Retinopathy Study visual acuity and refraction data were also collected at each time. Retinal thickness measurements from each of the nine macular Early Treatment Diabetic Retinopathy Study areas of the retina map, visual acuity, and refraction were plotted over time.

RESULTS

Mean retinal thickness remained unchanged in all retinal sectors over the course of the day for the controls and the 6 diabetic patients with a baseline foveal thickness of <300 mum, and it significantly decreased in 7 of the 9 retinal sectors for the 9 diabetic patients with a baseline foveal thickness of > or =300 microm (ANOVA model for repeated measures). In these patients, the mean initial foveal thickening +/- SD of 211 +/- 104 microm was reduced by an average of 6.1%, 15.2%, and 21.2% at 12 pm, 3 pm, and 6 pm, respectively. Two of these nine patients also had an increase in visual acuity without change in refraction. There were no changes in refractive errors over the course of the study in the two groups. A positive correlation between initial central thickening and decrease in thickness was found (r = 0.732; P = 0.002).

CONCLUSION

This study suggests that macular thickening, as measured by the Stratus OCT, may spontaneously decrease in some patients with more severe CSME over the course of the day, and it confirms previous findings. However, in our study, the entity of this decline was relatively small and not relevant from a clinical standpoint.

Interneurons transiently express the ERG K+ channels during development of mouse spinal networks in vitro

During spinal cord maturation neuronal excitability gradually differentiates to meet different functional demands. Spontaneous activity, appearing early during spinal development, is regulated by the expression pattern of ion channels in individual neurons. While emerging excitability of embryonic motoneurons has been widely investigated, little is known about that of spinal interneurons. Voltage-dependent K+ channels are a heterogeneous class of ion channels that accomplish several functions. Recently voltage-dependent K+ channels encoded by erg subfamily genes (ERG channels) were shown to modulate excitability in immature neurons of mouse and quail. We investigated the expression of ERG channels in immature spinal interneurons, using organotypic embryonic cultures of mouse spinal cord after 1 and 2 weeks of development in vitro. We report here that all the genes of the erg family known so far (erg1a, erg1b, erg2, erg3) are expressed in embryonic spinal cultures. We demonstrate for the first time that three ERG proteins (ERG1A, ERG2 and ERG3) are co-expressed in the same neuronal population, and display a spatio-temporal distribution in the spinal slices. ERG immuno-positive cells, representing mainly GABAergic interneurons, were present in large numbers at early stages of development, while declining later, with a ventral to dorsal gradient. Patch clamp recordings confirmed these data, showing that ventral interneurons expressed functional ERG currents only transiently. Similar expression of the erg genes was observed at comparable ages in vivo. The role of ERG currents in regulating neuronal excitability during the earliest phases of spinal circuitry development will be examined in future studies.

Efficacy of ACE-inhibitor therapy on renal disease in glycogen storage disease type 1: a multicentre retrospective study

BACKGROUND

The efficacy of ACE-inhibitors in decreasing microalbuminuria and proteinuria has been reported in a few patients with glycogen storage disease type 1 (GSD1); however, no case-control study has ever been published.

AIM

The aim of the current study was to evaluate the efficacy of ACE-inhibitors in reducing glomerular hyperfiltration, microalbuminuria and proteinuria, and in delaying the progression of renal damage.

PATIENTS AND METHODS

Ninety-five patients (median age at the time of the study: 14.5 years) were enrolled from nine Italian referral centres for metabolic diseases. A retrospective study of a 10-year follow-up was conducted in order to compare the evolution of these parameters in treated patients with those who were not treated with ACE-inhibitors.

RESULTS

A significant and progressive decrease of glomerular filtration rate was observed in treated patients vs. those who were not treated with ACE-inhibitors (P < 0.05). No difference was observed for microalbuminuria and proteinuria between the two groups of patients. Moreover, the ACE-inhibitors significantly delayed the progression from glomerular hyperfiltration to microalbuminuria, but not that from microalbuminuria to proteinuria.

CONCLUSIONS

The results of the present study underline the importance of a strict follow-up of renal function in GSD1 patients. The detection of glomerular hyperfiltration suggests precocious initiation of ACE-inhibitor treatment to delay the progression of renal damage. A randomized prospective study is needed to establish for certain the real effectiveness of this treatment in GSD1 patients.

Reconstitution of lymphocyte subpopulations in children with inherited metabolic storage diseases after haematopoietic cell transplantation

We prospectively evaluated the reconstitution of lymphocyte subpopulations in nine children with lysosomal diseases who underwent 11 allogeneic haematopoietic cell transplants (HCTs) following CD34(+) immunomagnetic enrichment, limited T-cell addback and in vivo B-cell depletion. Absolute lymphocyte count recovery was slow to cross the 5th percentile, occurring at a median of 10 months after HCT in patients with full chimaerism. Natural killer cells represented up to 90% of the total lymphoid population during the first 3 months. CD4(+) lymphocyte recovery occurred 9-18 months after HCT. In most patients, CD8(+) lymphocyte recovery was slow and comparable with that of CD4(+) lymphocytes. The CD4(+)/CD8(+) ratio normalised by 3-7 months after HCT in 50% of the patients. CD8(+) lymphocyte recovery was enhanced in patients with viral reactivation. Reconstitution of B-lymphocytes was particularly delayed in patients treated with rituximab. Declining chimaerism, rejection and viral reactivation were the most common problems in our series. Because of the unique graft manipulation, the pace of lymphocyte reconstitution was particularly slow, suggesting that these patients are at a significantly increased risk of infections for up to 2 years after HCT.