Table 3.

Selected Genes to Consider in the Differential Diagnosis of KCNQ3-SLFNE and KCNQ3-SLFIE

Gene(s)PhenotypeMOIClinical Features
KCNQ2 Self-limited familial neonatal epilepsy (SLFNE) (See KCNQ2-Related Disorders.)ADThe frequency of KCNQ2 pathogenic variants as a cause of SLFNE is more than tenfold that of KCNQ3 pathogenic variants. KCNQ2-SLFNE & KCNQ3-SLFNE are clinically indistinguishable; thus, molecular genetic testing of both genes is commonly performed when SLFNE is suspected.
PRRT2
SCN2A
SCN8A 		Self-limited familial infantile epilepsy (SLFIE) & self-limited familial neonatal-infantile epilepsy (SLFNIE) (See PRRT2-Associated Paroxysmal Movement Disorders, SCN8A-Related Epilepsy and/or Neurodevelopmental Disorders, & OMIM PS601764.)ADPRRT2 is the most commonly involved gene for SLFIE. While some persons w/PRRT2 pathogenic variants develop paroxysmal kinesigenic dyskinesia later in life, clinical characteristics early in life do not differ from KCNQ3-SLFIE. SLFIE & SLFNIE can closely resemble SLFNE in rare instances. In SLFIE, seizure onset is nearly always by age ~6 mos. In SLFNIE, age of seizure onset can vary w/in a family & incl both neonatal & infantile onset. 1

AD = autosomal dominant; MOI = mode of inheritance

1.

From: KCNQ3-Related Disorders

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