In-Silico Analysis of Gene ALS2 Genetic Variants Identified in the Affected Horses and Humans With Motor Neuron Disease

Motor neuron disease (MND) is a spontaneous neurologic disorder of humans and adult horses, which results from the degeneration of motor neurons in the spinal cord and brain stem. The etiology of MND disease in the South Asian region is not well understood. To achieve the objective of the study, blood samples were collected from both affected humans and horses. DNA was purified by inorganic method; subsequently, ALS2 gene was sequenced both in humans and horses of Pakistani origin diagnosed with MND. In case of affected individuals, by targeted sequencing, we identified two novel ALS2 mutations, the missense substitution c.194T>C (p.Phe65Ser) located in the first RCC1 domain of ALS2 and the nonsense mutation c.2998delA (p.Ile1000*) located in the PH domain of ALS2. In case of affected horses, we identified two missense substitution mutations c.247G>A (p.Ile83Val) and c.914T>G (p.Leu305Arg) in the ALS2 gene. In-silico analysis was performed by PolyPhen-2 and SIFT of identified genetic variants to predict whether a substitution of specific amino acid affects protein function and to understand the pathogenicity of identified genetic variants. Our results suggest that genetic variants identified in human families were found to be pathogenic, whereas missense substitutions identified in horse ALS2 gene were not causing MND in affected horses.