The challenge in rare diseases is insufficient knowledge. This can lead to under-diagnosis, misdiagnosis, delays in diagnosis and inappropriate treatment. Research helps to address this. Over 200 papers are reported on in “The McArdle Disease Handbook”, and here we provide links to more selected recent research papers of interest, and landmark papers. Use the buttons on the right to jump to the two sections.
These papers are listed in reverse date order and we have allocated keywords to help you search for what you want.
PATIENT-REPORTED EXPERIENCES WITH A LOW-CARBOHYDRATE KETOGENIC DIET: AN INTERNATIONAL SURVEY IN PATIENTS WITH MCARDLE DISEASE
Nutrients, February 2023
With many individuals with McArdle disease having tried a LCKD, this study collected patient-reported experiences, both positive and negative. 183 responses were collected from individuals with McArdle’s from 18 countries. One-third had tried a LCKD, and almost 90% experienced some degree of positive effect on activity intolerance, muscle pain, and muscle fatigue. Adverse effects were rare and generally mild to moderate. These findings underline the need for randomized clinical trials to determine if a LCKD is a suitable nutritional strategy for McArdle’s.
MUSCLE GLYCOGEN UNAVAILABILITY AND FAT OXIDATION RATE DURING EXERCISE: INSIGHTS FROM MCARDLE DISEASE
Journal of Physiology, November 2022
Carbohydrate availability affects fat metabolism during exercise; however, the effects of complete muscle glycogen unavailability on maximal fat oxidation (MFO) rate remain unknown. Our purpose was to examine the MFO rate in patients with McArdle disease, compared to healthy controls. Despite having a much lower VO2peak, patients showed considerably higher values for the MFO rate, and for the FATmax and MFO rate-associated workload than controls. In summary, patients with McArdle disease show an exceptionally high MFO rate, which they attained at near-maximal exercise capacity.
CLINICAL PRACTICE GUIDELINES
CLINICAL PRACTICE GUIDELINES FOR GLYCOGEN STORAGE DISEASE V & VII (MCARDLE DISEASE AND TARUI DISEASE) FROM AN INTERNATIONAL STUDY GROUP
Neuromuscular Disorders, December 2021
The Guidelines, developed by an international team of clinicians and researchers led by IamGSD, are published in Neuromuscular Disorders, the official journal of the World Muscle Society. A significant landmark in the progress of the understanding and treatment of McArdle’s and Tarui disease. Available to all free of charge under Open Access.
NO EFFECT OF ORAL KETONE ESTER SUPPLEMENTATION ON EXERCISE CAPACITY IN PATIENTS WITH MCARDLE DISEASE
Neuromuscular Disorders, October 2021
A randomized placebo-controlled cross-over study. An increase in KB oxidation by oral KE supplementation cannot fully compensate for the KB-induced inhibition of lipolysis and glycolysis, explaining why the drink failed to improve exercise capacity. Thus, oral KE supplementation alone cannot be recommended as treatment option for patients with GSDV.
COHORT • COMORBIDITIES
NATURAL HISTORY OF MCARDLE DISEASE: A SINGLE CENTRE STUDY OF A COHORT OF 220 PATIENTS
PAO • NUTRITION
INTERNATIONAL PATIENT GROUP HARNESSES SOCIAL MEDIA TO HELP INFORM RESEARCH: USE OF A LOW CARBOHYDRATE KETOGENIC DIET
Current Opinion in Endocrinology, Diabetes and Obesity, October 2021
To highlight the benefits of a partnership between patient advocacy organizations (PAO) and clinical researchers in order to clinically study the prior anecdotal patient experience of utilizing a low-carbohydrate ketogenic diet (LCKD) to manage McArdle disease.
MCARDLE DISEASE PATIENTS HAVE INCREASED FAT REPLACEMENT OF PARASPINAL MUSCLES: EUROPEAN MULTICENTER STUDY
Neuromuscular Disorders, July 2021
The aim of this study was to quantify fatty replacement of paraspinal and extremity muscles by magnetic resonance imaging (MRI) in a European cohort of patients with McArdle disease. The findings show that patients exhibit significant muscle fatty replacement in paraspinal muscles. This can have important implications for future management of patients.
THE POTENTIAL OF A KETOGENIC DIET TO MINIMIZE EFFECTS OF THE METABOLIC FAULT IN GSD V AND VII
Current Opinion in Endocrinology, Diabetes and Obesity, October 2020
To explore the potential of a low carbohydrate ketogenic diet (LCKD) to counter physical activity intolerance, pain and muscle damage for glycogen storage disease (GSD) V and VII, and highlight the realistic possibility that nutrition could be key.
EXERCISE • METABOLISM
INVESTIGATION OF THE EXISTENCE AND CHARACTERISTICS OF A “THIRD WIND” PHENOMENON IN MCARDLE DISEASE
Neuromuscular Disorders, October 2019
Fourteen participants walked at a self-selected pace on a motorised treadmill for 151 min (2 hr 31 min). Six were genetically confirmed GSDV (McArdle group) and eight were pathology free individuals (Control group). Expired gas samples were collected at selected timepoints throughout and calculations of fat and carbohydrate use were made using RER. In prolonged exercise up to 121 minutes those with McArdle disease appear to use different metabolism to those without pathology. Between minute 121 and 151 the non-linear rise in fat use in the McArdle group does suggest that there is a change at c2hr that could substantiate the suggestion of a ‘Third Wind’.
THE EFFECT OF TRIHEPTANOIN IN ADULTS WITH MCARDLE DISEASE
Annals of Clinical and Translational Neurology, September 2019
In other metabolic diseases studies of Triheptanoin diet have shown that Triheptanoin increased metabolism of both fat and sugar, and had a positive effect on physical performance and reduced the level of symptoms. However, in McArdle’s the interpretation of the findings was negative: “Despite increased resting plasma malate with Triheptanoin, the increase was insufficient to generate a normal TCA turnover during exercise and the treatment has no effect on exercise capacity or oxidative metabolism in patients with McArdle disease.”
CENTRE OF EXPERTISE: COMPREHENSIVE CARE FOR PATIENTS WITH MCARDLE DISEASE
Journal Rare Disorders: Diagnosis & Therapy, 2018
The limited prevalence of this disease translates into a global challenge of limited specialist care for patients with McArdle disease. A Centre of Expertise (CoE) represents the most expansive platform to provide patients with McArdle disease current best practice that encompass thorough assessments, accurate diagnostic methods, relevant information and guidance, multidisciplinary support and an ongoing interface between primary and specialist care.
MISDIAGNOSIS AND DIAGNOSTIC DELAY IN MCARDLE DISEASE
COHORT • GENETICS
GENOTYPIC AND PHENOTYPIC FEATURES OF ALL SPANISH PATIENTS WITH MCARDLE DISEASE: A 2016 UPDATE
NUTRITION • EXERCISE
CAN A LOW-CARBOHYDRATE DIET IMPROVE EXERCISE TOLERANCE IN MCARDLE DISEASE
Journal Rare Disorders: Diagnosis and Therapy, 2017
A carbohydrate-restricted diet may provide patients with McArdle disease with a consistent energy substrate for working muscles, thereby reducing the risk of muscle damage and threat of renal failure. Further research on the use of a LCKD in McArdle disease is warranted.
GENETICS • METABOLISM
HIGHER OXIDATIVE STRESS IN SKELETAL MUSCLE OF MCARDLE DISEASE PATIENTS
EXERCISE • NUTRITION
EXERCISE AND PRE-EXERCISE NUTRITION AS TREATMENT FOR MCARDLE DISEASE
Medicine and Science in Sports and Exercise, 2016
Review of the role of exercise in McArdle disease with the aim to better inform health-care professionals and thus better serve the interests of patients. Recommendations for regular exercise together with preexercise nutrition in children and adult patients are also provided along with examples of exercise practice and its benefits.
NUTRITION • METABOLISM
DIFFERENTIAL GLUCOSE METABOLISM IN MICE AND HUMANS AFFECTED BY MCARDLE DISEASE
APS Physiological Genomics, August 2016
Carbohydrate metabolism in terms of glucose transport, glycolysis, glycogen synthesis, and glycogen breakdown in proximal and distal hind limb muscles from adult homozygous “McArdle” (PYGM p.R50X/p.R50X) and wild-type (wt/wt) mice were studied. In addition, this study compares potential changes in glucose homeostasis.
GENETICS • EXERCISE
GENES AND EXERCISE INTOLERANCE: INSIGHTS FROM MCARDLE DISEASE
Physiological Genomics, 2016
Regular physical activity attenuates the clinical severity of McArdle disease. This is quite remarkable for a monogenic disorder that consistently leads to the same metabolic defect at the muscle tissue level, that is, complete inability to use muscle glycogen stores. Further knowledge of this disorder would help patients and enhance understanding of exercise metabolism as well as exercise genomics. Indeed, McArdle disease is a paradigm of human physical activity intolerance and PYGM genotyping should be included in the genetic analyses that might be applied in the coming personalized exercise medicine as well as in future research on genetics and exercise-related phenotypes.
PSYCHOLOGY • RARE DISEASE
WALKING WITH MCARDLE DISEASE: ALIENATION AND SOLIDARITY IN A RARE DISEASE JOURNEY
Rare Diseases and Orphan Drugs, 2015
First-hand written narratives are a particularly valuable resource for understanding the lived experience (as opposed to the medical facts) of disease. A person with McArdle disease, a very rare disorder of muscle, wrote an account of her 32-day trek across the countryside and mountains of Wales. Her narrative is in the form of a daily diary detailing the events of each day’s walking, together with her thoughts and feelings. I present an inductive and semantic analysis of this text. Prominent themes include the alienation of having a rare disease, but also a strong sense of solidarity in the journey, and the normal pleasures and tribulations of walking the British countryside.
CARDIORESPIRATORY FITNESS, PHYSICAL ACTIVITY, AND QUALITY OF LIFE IN PATIENTS WITH MCARDLE DISEASE
Medicine & Science In Sports & Exercise, 2014
All patients showed a CRF below their age-/sex-matched normality value and scored clinically lower in the physical component summary and in most SF-36 domains compared with the Spanish general population. Patients showed a consistent link between higher physical HRQoL scores and higher CRF. Patients fulfilling leisure time PA recommendations showed higher CRF and physical HRQoL scores than those not meeting guideline recommendations. According to normative data for healthy subjects, CRF and physical HRQoL are severely impaired in adult patients with McArdle disease.
There are a number of papers which deserve recognition as landmarks in the understanding of McArdle disease and other muscle GSDs. We are going to list them for you here.