A change in gene structure could result in a variant form that may be transmitted to the next generation. The genetic change (mutation) may lead to varying results. One of them is its effect on the function of the gene. Some mutations may lead to a complete loss of function whereas others may cause only a partial loss of function. Thus, as to the question whether the mutation completely eliminates or simply reduces the function of the gene, geneticists determine the effects of gene mutation and classify it accordingly. Mutation may be amorphic mutation, hypermorphic mutation, hypomorphic mutation, or neomorphic mutation. In amorphic mutation, the mutation leads to a gene product that loses the detectable normal or the wild-type function of the gene. Often, the phenotypes associated with this type of mutation are recessive. 1
1Meneely, P., & Meneely, P. (2014). Genetic analysis: Genes, genomes, and networks in eukaryotes (Second ed.).