Our verdict is Likely benign. Variant got -6 ACMG points: 0P and 6B. BP4_ModerateBS2
The NM_000726.5(CACNB4):c.571A>T(p.Thr191Ser) variant causes a missense change. The variant allele was found at a frequency of 0.0000112 in 1,604,274 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 13/21 in silico tools predict a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★★).
CACNB4 (HGNC:1404): (calcium voltage-gated channel auxiliary subunit beta 4) This gene encodes a member of the beta subunit family of voltage-dependent calcium channel complex proteins. Calcium channels mediate the influx of calcium ions into the cell upon membrane polarization and consist of a complex of alpha-1, alpha-2/delta, beta, and gamma subunits in a 1:1:1:1 ratio. Various versions of each of these subunits exist, either expressed from similar genes or the result of alternative splicing. The protein encoded by this locus plays an important role in calcium channel function by modulating G protein inhibition, increasing peak calcium current, controlling the alpha-1 subunit membrane targeting and shifting the voltage dependence of activation and inactivation. Certain mutations in this gene have been associated with idiopathic generalized epilepsy (IGE), juvenile myoclonic epilepsy (JME), and episodic ataxia, type 5. [provided by RefSeq, Aug 2016]
Review Status: criteria provided, single submitter
Collection Method: clinical testing
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Idiopathic generalized epilepsy Uncertain:1
Feb 24, 2022
Labcorp Genetics (formerly Invitae), Labcorp
Significance: Uncertain significance
Review Status: criteria provided, single submitter
Collection Method: clinical testing
This sequence change replaces threonine, which is neutral and polar, with serine, which is neutral and polar, at codon 191 of the CACNB4 protein (p.Thr191Ser). This variant is present in population databases (rs746415223, gnomAD 0.01%). This variant has not been reported in the literature in individuals affected with CACNB4-related conditions. ClinVar contains an entry for this variant (Variation ID: 585589). Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -