Abstract: Methods for determining the genetic predisposition of a human subject to developing ALS are provided herein. These methods include methods for determining the genetic predisposition to any form of ALS, as well as specific methods for determining the genetic predisposition to early onset, late onset, bulbar onset and limb onset ALS. The method can detect amyotrophic lateral sclerosis in a human subject or a specific form of ALS in the subject (early onset, late onset, bulbar onset or limb onset). The method can also detect the risk of developing amyotrophic lateral sclerosis (ALS) in a human subject. The methods utilize the detection of one or more haplotype bocks comprising tag single nucleotide polymorphisms (SNPs). In several embodiments, the methods including detecting the presence of one or more tag SNPs.