Liao, Ying, Qi, Jian-Guang, Yan, Hui et al. · Chinese medical journal · 2021 · DOI
This case report describes one adolescent patient who had three conditions at the same time: ME/CFS (chronic fatigue syndrome), postural tachycardia syndrome (a condition where heart rate increases abnormally when standing), and narcolepsy (excessive daytime sleepiness). The doctors discovered this patient had a genetic variation in the MTHFR gene, which is involved in processing folate and other important molecules in the body. The authors suggest this genetic variation might help explain why this patient developed all three conditions together.
Many ME/CFS patients experience overlapping conditions like PoTS and sleep disorders, making understanding shared biological mechanisms important. This report suggests a potential genetic factor (MTHFR mutation) that might predispose to multiple simultaneous conditions, which could eventually guide genetic screening and targeted treatment approaches. Identifying common genetic contributors could help researchers understand why certain patients develop clusters of related conditions.
This single case report cannot establish that MTHFR mutations cause ME/CFS, PoTS, or narcolepsy, nor can it prove these conditions share a common genetic basis. The presence of a genetic variation in one patient does not prove it is responsible for the conditions, as correlation does not equal causation. Large population studies would be needed to determine whether MTHFR mutations are actually more common in patients with these conditions compared to healthy controls.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
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