Skip to main content

L-alanine supplementation in Pompe disease (IOPD): a potential therapeutic implementation for patients on ERT? A case report



Pompe disease (PD) is a disorder of glycogen metabolism conditioning a progressive and life conditioning myopathy. Enzyme replacement therapy (ERT) is currently the best treatment option for PD, but is not resolutive. While other potential therapeutic approaches have been reported before, these have never been tried as co- treatments. L-alanine oral supplementation (LAOS) has been proven to reduce muscle breakdown: we hereby report the first case of supplementation on a PD patient on ERT.

Case presentation

F. is a 9 y.o. infantile onset Pompe Disease (IOPD) girl ERT-treated since age 1 developing a progressive myopathy. We started her on LAOS and performed assessments at baseline, 6 and 9 months. At baseline, F.’s weight, height and BMI were within normal ranges, while body composition showed low fat mass -FM and high resting energy expenditure—REE levels. After LAOS, a progressive FM increase and REE reduction could be observed both at 6 and 9 months.


ERT is not curative for PD patients thus additional treatments could be considered to improve outcomes. Our patient showed physical signs of inability to accumulate energy when exclusively on ERT, while FM increase and REE reduction occurred when supplemented with LAOS, likely reflecting anabolic pathways’ implementation. This is the first case reporting potential LAOS benefits in PD-on ERT patients. Longitudinal case control studies are yet needed to evaluate possible efficacy of combined LAOS And ERT treatment in PD patients.


Pompe disease (PD), or glycogen storage disorder type II (GSD II; OMIM 232,300), is an inherited lysosomal disorder due to the deficiency of the acid a-glucosidase enzyme (GAA, EC causing multisystemic glycogen accumulation [1]. The latter leads to variable associated phenotypes: from severe rapidly progressive forms, usually presenting with hypertrophic cardiomyopathy, to slowly progressive later-onset forms with typical muscular weakness, especially in the legs and the trunk, that can occur from early childhood to late adulthood and typically without cardiac involvement. Numerous causing variants in the GAA gene have been described to date, mostly homozygous or in compound heterozygosity, defining a continuous spectrum of clinical presentations [2] for which it is difficult to establish a strict genotype/phenotype correlation. Enzyme-replacement therapy (ERT) with recombinant human GAA (rhGAA) [3, 4] is currently the main treatment available for patients, as it seems capable of highly reverting cardiac muscle involvement and extending life expectancy in infantile patients; still, it seems lacking in treating residual symptoms, e.g. skeletal muscle involvement [5]. Before ERT, many other potential treatment strategies have been attempted, such as dietary interventions and oral supplementions [6,7,8,9], as inactivity and/or inadequate/excess food intake were shown to maybe play a crucial role accelerating disease progression [10]. Among those tried, L-alanine supplementation has been shown to reduce protein degradation and muscle breakdown, being a gluconeogenic amino acid capable of decreasing branched-chain AA catabolism even with relatively short period treatment-trials [11]. This is also cheap, palatable and well tolerated by patients, with minimal energy burden [12]. Reported trials have been in ERT naïve patients to date, while supplementation has never been tried in on-ERT PD patients and potential outcomes are yet to be described.

Case presentation

F. is a 9 yo IOPD affected girl born at term after an uneventful pregnancy and neonatal period. Unremarkable family history. At age 1 m.o., due to the incidental finding of heart murmur, heart US was performed and resulted normal. At age 7 m.o. she was admitted for pneumonia and hypertransaminasemia (AST 168 U/L, n.v 14–36 U/L, ALT 102 U/L, n.v. 9–52 U/L). Chest X-ray showed left pulmonary thickening with no cardiomegaly. At that time, there was no history of feeding problems, failure to thrive, hypotonia or muscle weakness. Pneumonia remitted after a standard antibiotic therapy, but hypertransaminasemia and altered levels of other serum muscle breakdown enzymes persisted at several follow ups (AST up to 388 U/L, ALT up to 164 U/L, CPK up to 942 U/L, n.v. 30-135U/L, LDH up to 4851 U/l, n.v. 313–618 U/L). Most frequent causes of such enzymes alterations were ruled out throughout follow up until signs of left ventricular hypertrophy could be highlighted at the ECG, which was followed by heart US confirming mild biventricular hypertrophy. F. was then again admitted at age 1 yo. while developing mild limbs tongue protrusion, hypotonia and hyporeflexia, though still preserving axial tone suggesting a peripheral cause such as a myopathy. Abdominal US, EEG and brain MRI were performed and resulted normal. Diagnostic suspicion of PD emerged, thus alfa-glucosidase activity dosage was performed resulting absent in fibroblasts and low in leukocytes (0.22 U.M, normal value > 0.35 U.M.). Molecular GAA gene analysis subsequently confirmed compound heterozygosis for 2 previously described variants (c.1655 T > C, p.Leu552Pro described as severe [13]; c.1927G > A, p.Gly643Arg described as less severe and associated with Late-Onset PD [14]). After CRIM assessment (resulted positive), ERT was started immediately (Myozyme®, iv, 20 mg/kg/2 weeks) and cardiac hypertrophy reverted and was complete already after 8 months of ERT initiation. Antibody status was monitored and seroconversion was gained after 6 months of therapy (maximum reached titer to date is 1600, stable in the last years; no immunomodulatory therapy has been started to date). Nutritional counselling ensured a high protein diet (> 25% of energy requirements as suggested by literature for PD patients [6, 7]) and adequate intakes of other macro and micronutrients according to LARN (Nutrient and energy reference intake levels for the Italian population) [15], with a 3 days dietary food record repeatedly performed for monitoring purposes [16]. F. always showed a linear growth-rate with anthropometric indices comparable to healthy population. Despite early beginning of ERT, F. is developing slowly progressive myopathy conditioning walking difficulties, moderate respiratory impairment and oropharyngeal dysphagia. Muscle MRI was performed, demonstrating bilateral gluteal muscle hypotrophy with preserved trophism of the thigh and leg muscles in the absence of significant signs of fibroadipose infiltration; also hyperintensity of the anterior lodge muscles was found (especially the quadriceps).

We tried to investigate our patient for testing possible effects of L-alanine oral supplementation (LAOS) during ERT. Anthropometric measures, including weight, height and BMI were evaluated and relative z-scores generated using the WHO 2007 growth charts [17]. Body composition was assessed using air displacement plethysmography (BOD-POD®), providing fat mass (FM), fat free mass (FFM) and relative percentages according to McCarthy 2006 percentiles [18]. Indirect calorimetry [19] (Q-NRG, Cosmed®) was used to measure resting energy expenditure (REE) under standardized conditions. Prior to study start, dietary habits were analyzed with a 3-days-food dietary record. The patient was then requested not to change dietary habits or exercise pattern throughout the study. Plasmatic alanine levels, alanine/lysine ratio, muscle enzymes, renal function and nutritional indices were included in the study protocol as monitored indices. L-alanine was administered as powder, mixed into a drink or creamy food (mainly milk or yogurt), starting at age 8 yo and 6 mo, with a starting dose of 0.5 g/kg/day TTD for a total of 15 g/day. Dosage was maintained unchanged for 6 months total (T1), then increased to 0.6 g/kg/day (total 18 g/day) for other 3 months (T2, 9 months after LAOS start). Patient was instructed to have an usual overnight fasting for biochemical examinations to be performed during the morning, in a fasting state and a thermo-neutral environment with the patient supine and awake [19]. Assessments took place at baseline (T0), at 6 (T1) and 9 months (T2).

At baseline, F.’s weight, height and BMI were within normal ranges, while BC demonstrated low FM (9.9%, < 2°pc) and high REE levels (112%, 1265 kcal/day vs. predicted WHO rates = 1133 kcal/day). These results, especially those related to FM, were in line with MRI previous findings (high intensity on T2WIs might suggest fatty infiltration or edema/inflammation and STIR can differentiate between them: suppressing fat signals, inflammation/edema was confirmed as major possible causal factor, thus low FM was in line with findings). 3-days-food dietary record analysis confirmed a diet higher in proteins (≥ 3.0 g/kg/day), corresponding to 20–25% of total daily energy intakes. This remained unchanged throughout all study period and still is ongoing. During the study period, the patient was compliant with LAOS treatment protocol and could complete all assessments due, no complications occurred. A progressive FM increase (9.9% 11.6% 13.4%) could be observed over the study period (Table 1) and IC-REE, remarkably high at baseline [20], decreased with a variation of 10% at T2 (44.7 to 40 kcal/kg/day). These modifications were significant: a statistically significant association was found between LAOS and time (p-value 0.004) (Fig. 1). IC-REE, expressed as Kcal/day, decreased with a variation of 3.6% compared to an expected increased (+ 2.1; + 4.2; + 4.3) according to Harris Benedict, Schofield and WHO respectively (Table 2). Changes in biochemical indices were unremarkable over study period and indices of muscle damage remained substantially unchanged, including ALT, AST, CPK, LDH, transthyretin, albumin, Ala/Lys ratio and lactate. No increases above considered normal values in Alanine blood concentrations could be observed during study period. On a patient’s perspective, even if difficult to objectify, it’s good to report that F. is now reducing the need of walking supports, she’s capable of standing and walking alone and can now sleep without any pillows.

Table 1 Anthropometric measures and evaluated indices of body composition before and during LAOS
Fig. 1
figure 1

Time-REE correlations with LAOS, patient on treatment vs. expected patient’s REE without intervention. Shapiro–Wilk normality test and repeated-Measures ANOVA were performed (with statistical significance p-value set at < 0.05) for studying the variables at each studied time with data grouped into two categories. First group contained the variables of basal metabolism repeated at 3 times of our patient (red line). Second group contained instead the expected basal metabolism variables without intervention, obtained with three different formulas* (Harris Benedict-REE; Schofield-REE; WHO-REE) at same three different times and based on patient’s parameters (black line). A statistically significant association can be found between intervention and time with the basal metabolism of our patient (p-value 0.004)

Table 2 REE parameters analysis obtained from indirect calorimetry (IC) compared to prediction with commonly used equations

Discussion and conclusions

Pompe disease is known to cause a severe progressive myopathy and other harmful clinical issues. At present, ERT has been proven to be successful delaying and halting progression of the disease, however myopathy remains present and can progress thus a critical evaluation of other potential beneficial therapies is still needed to enhance the approach to PD. Myopathy’s etiopathogenesis in PD is yet to be completely understood but the progressive glycogen accumulation in lysosomes and related membranes damage seems to be responsible for the muscle contractile units’ impairment. Nonetheless, there is recent evidence on a possible defective pathway along autophagic ways that could play a major role in muscle damage [21]. Although little is yet known about these processes, it’s unquestionable that muscle atrophy occurs when the balance between protein synthesis and degradation is unbalanced and shifted in favor to the latter [22]. Several approaches have been studied over years to obtain a slowdown in protein breakdown and consequent muscle damage. Among those, diets higher in proteins and a potential L-Alanine supplementation seem to be the most favorable, the first ensuring an increased pool of amino acids which could make up for the proteolysis and slow down the muscular damage progression [6, 23], the latter being a gluconeogenetic aminoacid thus enhancing glucose availability and sparing the branched-chain aminoacids leading to reduced leucine oxidation (an indirect index of protein breakdown) [11]. Such interventions have been tried to date only before ERT advent and demonstrated a REE reduction [12] and increase in muscle mass [24] defining a possible valid approach to reduce proteolysis. Despite this, after ERT approval this approach has never been tested again and focus has shifted on how to avoid FM reduction as marker of muscle substitution. Even if this could be relevant for clinical purposes, there is also evidence in literature on how possibly an overmuch FM reduction could also be disadvantageous: healthy or underweight individuals with reduced FM seem to be at higher risk of frequent events of chronic obstructive pulmonary disease [25]. These observations led us to investigate more, attempting a L-Alanine oral supplementation in a IOPD patient on ERT. Before LAOS, our patient demonstrated a normal BMI with low FM and elevated REE, reflecting the potential patient’s inability to accumulate energy and the predominance of catabolic over anabolic processes as eventual index of increased protein breakdown. Over study period, a positive change in body composition with increasing FM percentages and a reduction of REE could be observed. Although BMI remained substantially unchanged, the meaningful reduction of REE can reflect the improvement in body composition and energy balance with implementation of anabolic pathways. Body composition standards for PD patients are not known, also considering the wide range of disease clinical presentation, and there are no specific-to-disease growth charts available. We then used general population as targeted comparison, aiming to reach similar FM/FFM distribution to optimize metabolic functioning. There is still lack of evidence about the translation of improved body composition in functional outcomes and the role of L-alanine supplementation in clinical improvements. However, our results suggest that LAOS may improve body composition and ameliorate resting metabolism in PD patients even on-ERT thus should be implemented in treatment protocols. Longer time-periods of LAOS and studies on larger numbers of patients are needed to confirm and ensure our results and to fix optimal dosage to be used, but we expect that they could highlight even more significant clinical changes.

Availability of data and materials

All data are stored in the San Paolo Hospital of Milan (Italy), Clinical Department of Pediatrics.

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.



Pompe disease


Enzyme replacement therapy


L-alanine oral supplementation


Body mass index


Fat mass


Fat free mass


Resting energy expenditure


Body composition


Glycogen storage disorder


Acid a-glucosidase enzyme






Magnetic resonance imaging


Cross Reactive Immunological Material


Three times a day


World Health Organization


  1. A.J.J. Reuser, R. Hirschhorn, M.A. Kroos, Pompe Disease: Glycogen Storage Disease Type II, Acid α-Glucosidase (Acid Maltase) Deficiency, in: D.L. Valle, S. Antonarakis, A. Ballabio, A.L. Beaudet, G.A. Mitchell, The Online Metabolic and Molecular Bases of Inherited Disease. The McGraw-Hill Companies (2001), 3389–3420

  2. Peruzzo P, Pavan E, Dardis A. Molecular genetics of Pompe disease: a comprehensive overview. Ann Transl Med. 2019;7:278.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Van den Hout H, Reuser AJ, Vulto AG, Loonen MC, Cromme-Dijkhuis A, Van der Ploeg AT. Recombinant human alpha-glucosidase from rabbit milk in Pompe patients. Lancet. 2000;356:397–8.

    Article  PubMed  Google Scholar 

  4. Amalfitano A, McVie-Wylie AJ, Hu H, et al. Systemic correction of the muscle disorder glycogen storage disease type II after hepatic targeting of a modified adenovirus vector encoding human acid-alpha-glucosidase. Proc Natl Acad Sci USA. 1999;96:8861–6.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Schoser B, Hill V, Raben N. Therapeutic approaches in glycogen storage disease type II/Pompe Disease. Neurotherapeutics. 2008;5:569–78.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Slonim AE, Coleman RA, McElligot MA, et al. Improvement of muscle function in acid maltase deficiency by high-protein therapy. Neurology. 1983;33:34–8.

    Article  CAS  PubMed  Google Scholar 

  7. Slonim AE, Bulone L, Goldberg T, et al. Modification of the natural history of adult-onset acid maltase deficiency by nutrition and exercise therapy. Muscle Nerve. 2007;35:70–7.

    Article  CAS  PubMed  Google Scholar 

  8. Umpleby AM, Trend PS, Chubb D, et al. The effect of a high protein diet on leucine and alanine turnover in acid maltase deficiency. J Neurol Neurosurg Psychiatry. 1989;52:954–61.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  9. Demey HE, Van Meerbeeck JP, Vandewoude MF, Prové AM, Martin JJ, Bossaert LL. Respiratory insufficiency in acid maltase deficiency: the effect of high protein diet. J Parenter Enteral Nutr. 1989;13:321–3.

    Article  CAS  Google Scholar 

  10. Batsis JA, Villareal DT. Sarcopenic obesity in older adults: aetiology, epidemiology and treatment strategies. Nat Rev Endocrinol. 2018;14:513–37.

    Article  PubMed  PubMed Central  Google Scholar 

  11. Kelts DG, Ney D, Bay C, Saudubray JM, Nyhan WL. Studies on requirements for amino acids in infants with disorders of amino acid metabolism, I. Effect of alanine. Pediatr Res. 1985;19:86–91.

    Article  CAS  PubMed  Google Scholar 

  12. Bodamer OA, Halliday D, Leonard JV. The effects of l-alanine supplementation in late-onset glycogen storage disease type II. Neurol. 2000;55:710–2.

    Article  CAS  Google Scholar 

  13. Bodamer OA, Haas D, Hermans MM, Reuser AJ, Hoffmann GF. L-alanine supplementation in late infantile glycogen storage disease type II. Pediatr Neurol. 2002;27:145–6.

    Article  PubMed  Google Scholar 

  14. Semplicini C, Letard P, De Antonio M, et al. Late-onset Pompe disease in France: molecular features and epidemiology from a nationwide study. J Inherit Metab Dis. 2018;41:937–46.

    Article  CAS  PubMed  Google Scholar 

  15. LARN. Nutrients and energy reference intake for Italian Population, 4th Rev. SINU (Italian Sociaety of Human Nutrition). 2014.

    Google Scholar 

  16. Crawford PB, Obarzanek E, Morrison J, Sabry ZI. Comparative advantage of 3-day food records over 24-hour recall and 5-day food frequency validated by observation of 9- and 10-year-old girls. J Am Diet Assoc. 1994;94:626–30.

    Article  CAS  PubMed  Google Scholar 

  17. 2007 WHO Reference (Growth reference 5–19 years). Accessed 13 Jan 2021.

  18. McCarthy HD, Cole TJ, Fry T, Jebb SA, Prentice AM. Body fat reference curves for children. Int J Obes (Lond). 2006;30:598–602.

    Article  CAS  Google Scholar 

  19. Fullmer S, Benson-Davies S, Earthman CP, et al. Evidence analysis library review of best practices for performing indirect calorimetry in healthy and non-critically ill individuals. J Acad Nutr Diet. 2015;115:1417–46.

    Article  PubMed  Google Scholar 

  20. Energy and protein requirements. Report of a joint FAO/WHO/UNU Expert Consultation. World Health Organ Tech Rep Ser. 1985;724:1–206.

    Google Scholar 

  21. Palhegyi AM, Seranova E, Dimova S, Hoque S, Sarkar S. Biomedical Implications of Autophagy in Macromolecule Storage Disorders. Front Cell Dev Biol. 2019;7:179.

    Article  PubMed  PubMed Central  Google Scholar 

  22. Lim JA, Sun B, Puertollano R, Raben N. Therapeutic Benefit of Autophagy Modulation in Pompe Disease. Mol Ther. 2018;26:1783–96.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. K. Esposito, M.R. Improta, D. Giugliano, S2.5 The nutritional approach to Pompe disease, Acta Myol. 30 (2011) 208–209.

  24. Mundy HR, Williams JE, Cousins AJ, Lee PJ. The effect of L-alanine therapy in a patient with adult onset glycogen storage disease type II. J Inherit Metab Dis. 2006;29:226–9.

    Article  CAS  PubMed  Google Scholar 

  25. Yang L, Zhu Y, Huang JA, Jin J, Zhang X. A Low Lean-to-Fat Ratio Reduces the Risk of Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Patients with a Normal or Low Body Mass Index. Med Sci Monit. 2019;25:5229–36.

    Article  PubMed  PubMed Central  Google Scholar 

Download references


Not applicable.


This article did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Author information

Authors and Affiliations



VR designed the study, supervised and coordinated the work and revised the manuscript. MP collected clinical data and wrote first draft of the paper. JZ and AS collected anthropometric and body composition measures. JZ and VE performed data analysis and interpretation. VR, ARD, SP, GC, ES and GB revised the manuscript. All authors contributed to the final version of the paper. All authors read and approved the final manuscript.

Corresponding author

Correspondence to Valentina Rovelli.

Ethics declarations

Ethics approval and consent to participate

All procedures performed in this study were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This study was also approved by the ERB of the Clinical Department of Pediatrics of San Paolo Hospital, University of Milan.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher’s Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Rovelli, V., Zuvadelli, J., Piotto, M. et al. L-alanine supplementation in Pompe disease (IOPD): a potential therapeutic implementation for patients on ERT? A case report. Ital J Pediatr 48, 48 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI: