Hello everyone. I am familiar with the variant classification criteria proposed by the ACMG and other medical organizations, but I don't quite understand how this is translated into the context of autosomal recessive disorders. In particular, technically speaking, does stating that a specific variant is, say, definitely pathogenic, mean that:

a) the variant in a homozygous state is known to always cause the disease;

b) the variant in a heterozygous state with other functionally similar (e.g. identical-by-state) variant is known to always cause the disease;

or

c) the variant in a heterozygous state with other definitely pathogenic variants (even if functionally non-identical) is known to always cause the disease?

Thanks a lot in advance for helping me in clarifying this!