Table 3. Clinical information for cases of parental mosaicism.

Gene	Variant (hg19 position; coding DNA; protein)	Type of variant	Percent of variant reads	Coverage (read depth at variant position)	Parent: clinical information	Parent: onset of seizures	Proband: onset of seizures
SCN1A	chr2:166929897 G>A; c.235 G>A; p.Asp79Asn	Missense	12.6%	495	Unknown	Unknown	Unknown
KCNQ2	chr20:62076020 C>T; c.682 C>T; p.His228Tyr	Missense	27.1%	266	Unaffected	N/A	Neonatal
MECP2	chrX:153296354 C>T; c.925 C>T; p.Arg309Trp	Missense	19.9%	540	Unaffected	N/A	Infancy
SCN1A	chr2: 166909392 C>T; c.664 C>T; p.Arg222Ter	Nonsense	6.0%	847	Unaffected	N/A	Infancy
SCN1A	chr2:166852557 C>A; c.4547 C>A; p.Ser1516Ter	Nonsense	14.2%	690	Unaffected	N/A	Unknown
SCN1A	chr2:166929950 T>C; c.182 T>C; p.Leu61Pro	Missense	20.2%	1,011	Unaffected	N/A	Infancy
SCN1A	chr2:166850727 C>A; c.4781 C>A; p.Ser1594Tyr	Missense	15.8%	38	Unaffected	N/A	Early childhood
SCN1Aa	chr2:166894519 G>A; c.2713 G>A; p.Ala905Thr	Missense	N/A	N/A	Unaffected	N/A	Unknown
SCN2A	chr2: 166237633-166237635 GAA>-c.4477_4479delGAA; p.Glu1493del	In-frame deletion	9.0%	885	Unaffected	N/A	Infancy
SCN2A	chr2:166245211 G>A; c.4895 G>A; p.Arg1632Lys	Missense	16.4%	764	Unaffected	N/A	Neonatal
KCNQ2	chr20:62073785 T>A; c.790 T>A; p.Tyr264Asn	Missense	14.0%	172	Affected (mild compared with proband)	Infancy	Neonatal
SCN1A	chr2:166848302 T>C; c.5483 T>C; p.Leu1828Ser	Missense	18.1%	533	Affected (more severe compared with proband)	Neonatal	Unknown (asymptomatic in infancy)
SCN2A	chr2:166245224 C>G; c.4908 C>G; p.Ile1636Met	Missense	7.6%	885	Affected (mild compared with proband)	Infancy	Neonatal

N/A, not applicable.

^aSuspected germ-line mosaicism: both parents were negative by targeted dideoxy sequencing and two affected offspring were heterozygous for variant.