HLA associations with autoimmune disorders are extraordinarily strong. Same applies to infectious diseases, vaccine efficiency and checkpoint inhibitor efficiency.
While you can type HLA with classical techniques, the only really reliable way is really to use long reads.
Same applies to CYP enzyme superfamily, where variation is linked to some rare drug toxicity events for example.
We should all know our HLA and our CYP genotypes. Why 23andme does not even attempt to impute HLA is beyond my understanding.