Objective: To identify the mutation of the GABA(A)-receptor gamma 2 subunit gene (GABRG2) in a Chinese family with generalized epilepsy with febrile seizures plus (GEFS+ ) and analyze the genotype-phenotype correlations and its inheritance.
Methods: Genomic DNA was extracted from peripheral blood lymphocytes of the proband and other available members in the GEFS+ family. The coding regions and flanking intronic regions of the GABRG2 gene were screened for mutations using polymerase chain reaction (PCR) and direct DNA sequencing.
Results: There were 7 affected members in the three-generation family, in which one with febrile seizures (FS) and six with febrile seizures plus (FS+ ). This family was consistent with the diagnostic criteria of GEFS+ . The nonsense mutation c.1287G to A (p.W390X) in the GABRG2 gene was initially identified in the proband. Seven affected members (6 FS+ and 1 FS) and one unaffected member carried the mutation. The nonsense mutation c.1287G to A/p.W390X in the GABRG2 gene was co-segregated with the GEFS+ family. The penetrance rate was about 87.5%(7/8).
Conclusion: This GEFS+ family was consistent with autosomal dominant inheritance with incomplete penetrance. GABRG2 mutation is also a disease-causing mutation in Chinese GEFS+ patients. The p.W390X mutation has not been reported previously.