Because mutation in the mouse Mass1 gene was found to be the cause of audiogenic seizure susceptibility in the Frings mouse strain, Nakayama et al. (2002) screened for mutations in the GPR98, or MASS1, gene in individuals from ... Because mutation in the mouse Mass1 gene was found to be the cause of audiogenic seizure susceptibility in the Frings mouse strain, Nakayama et al. (2002) screened for mutations in the GPR98, or MASS1, gene in individuals from 48 families with familial febrile seizures showing suggestive evidence of linkage to 5q14. They identified 25 DNA alterations. None of 9 missense polymorphic alleles was significantly associated with febrile seizures; however, a nonsense mutation (S2652X; 602851.0001) causing a deletion of the C-terminal 126 amino acid residues was identified in 1 family with febrile and afebrile seizures. The results suggested that a loss-of-function mutation in MASS1 may be responsible for the seizure phenotype, but that mutation in the MASS1 gene is not likely to be a contributing factor in most families with febrile seizures.