Possibly, but that's not what this study is claiming. They're saying that certain SNPs are more common in ME/CFS patients, suggesting that those SNPs (and/or genes) contribute to developing ME/CFS.
I mentioned GRIK2 and COMT because they are two genes I've looked at in respect of ME/CFS. Several studies have associated COMT SNPs with ME/CFS but its also associated with many other conditions including most frequently schizophrenia, bipolar disorder, major depression. But in no condition is there a one to one relationship between a specific SNP and a specific disorder.
From what I could determine COMT SNPs may be a risk factor along with many other SNPs for developing a range of disorders (which may well share the same underlying pathophysiology). For example, having one or more of the met alleles of COMT val158met appears to predispose individuals to increased pain perception and deficits in executive function when under stress - regardless of what medical condition they have.
So certain SNPs may well be contributory risk factors to developing certain disorders (likely to involve neuroinflammation I'd propose) but not specifically to develop ME/CFS.
Not that this lack of specificity is a problem - psychiatry is rapidly moving to diagnosis based on the underlying pathology which cuts across symptom based diagnostic labels.