Table 1.

Summary of recent genetic studies in epilepsy

Syndrome	Gene	Type of study	Original finding	Follow-up finding	Study
JME	BRD2	Association analysis	Markers in BRD2 associated with Caucasian JME patients		Greenberg et al. [20], Pal et al. [21]
		Association analysis		BRD2 associated with photoparoxysmal response in a German population with mixed IGE-related phenotypes	Lorenz et al. [53]
		Association analysis		BRD2 found associated with JME in English and Irish population samples, but not in Indian, German, or Australian	Cavalleri et al. [25••]
		Linkage analysis	Linkage data suggested imprinting in EJM1 gene (later shown to be BRD2) at 6p21		Greenberg et al. [20]
		Population-based analysis of family affectedness data		Supports maternal inheritance of JME as well as increased female risk for JME	Pal et al. [28••]
	EFHC1	Mutation analysis	Mutations found in EFHC1 that segregate with disease in 5 of 44 families		Suzuki et al. [35••]
		Mutation analysis		No mutations segregating with disease found in other genes in the linkage region, supporting EFHC1's involvment in JME in this population.	Suzuki et al. [30]
		Mutation analysis		Found 5 mutations in EFHC1 in 61 IGE patients; mutations not seen in controls but meaning unclear	Stogmann et al. [33]
		Mutation analysis		Found variants of EFHC1 in population supporting linkage to the region but none that segregated with disease in families	Pinto et al. [32]
		Mutation/association analysis		No difference in cases and controls in EFHC1 coding polymorphisms	Ma et al. [31]
CAE	GABA receptor genes GABRA1, GABRG2, GABRB3		Reported in studies of single large families and association study		Baulac et al. [41], Wallace et al. [42], Feucht et al. [40, Cossette et al. [43]
	GABRB3	Association analysis		Found association with haplotypes in 45 CAE subjects	Urak et al. [36]
	GABRB3	Association analysis		Attempted to replicate Urak et al. [36] with larger sample and different IGEs but found no association	Hempelmann et al. [37]
	GABRG2	Association analysis		Tested SNPs in gene identified from linkage; no association but IGE type mixed	Chou et al. [38]
	GABRG2	Association analysis		Tested SNP association in several different forms of epilepsy; no association found	Kinirons et al. [39]
JME	GABRA1	Linkage analysis	Linked to JME in a single large family		Cossette et al. [43]
		Mutation analysis		Tested gene using 33 JME families similar to original; no mutations found	Ma et al. [31]
CAE	Calcium channel gene CACNA1H	Mutation analysis	Association with exon variants in CAE in Chinese Han population		Chen et al. [46]
		Mutation analysis		Found no variants nor any association (but this was in a European population, not Chinese)	Chioza et al. [45]
		Mutation analysis		Found 14 variants in 100 CAE patients (Chinese populations); significance unclear	Liang et al. [44]
Rolandic epilepsy		Twin study	Samples from 4 twin registries showed no evidence of increased concordance, suggesting no genetic component; study confounded by incomplete data collection and questionable sampling		Vadlamudi et al. [47]

CAE—childhood absence epilepsy; GABA—gamma-aminobutyric acid; IGE—idiopathic generalized epilepsy; JME—juvenile myoclonic epilepsy; SNP—single nucleotide polymorphism.