Preliminary evidence suggests that commonly used genetic tests may be less likely to identify a genetic etiology in ALS patients (pALS) of non-European geoancestry, as compared to European.  pALS of diverse geoancestry may therefore be less likely to have access to accurate and specific genetic counseling information and less likely to benefit from gene-targeted therapies currently in clinical trials.

The overall proportion of P and LP variants identified in pALS of European and non-European geoancestry was not significantly different, but pALS of European geoancestry were more likely to have the C9orf72 HRE (p<0.001).  The overall distribution of P and LP test outcomes in all ALS genes was significantly different between the two groups, with relatively more P and LP variants in genes other than C9orf72 identified in pALS of non-European geoancestry (p<0.009). 

As genetic testing becomes widely adapted in ALS clinics, the C9orf72 HRE test has been advocated as a first, and in some cases, only genetic test offered to pALS.  Since the HRE is less prevalent in non-European populations, this practice may result in reduced ascertainment of genetic ALS in pALS of diverse geoancestry.   Further study is needed to determine the need for population-specific genetic testing approaches in ALS.