I can't really help you because I'm not familiar with the use of a skin/nerve biopsy in the diagnosis. I have heard of muscle biopsy being used, they can see signs of muscle changes due to the nerve damage from
ALS. In that case a "normal" result would point away from
ALS (and would also point away from certain other muscle disorders). But again I'm not sure whether your husband's biopsy was the same as this.