Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PVS1_StrongPM2PP5_Moderate
The NM_201525.4(ADGRG1):c.10C>T(p.Gln4*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,332 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★).
ADGRG1 (HGNC:4512): (adhesion G protein-coupled receptor G1) This gene encodes a member of the G protein-coupled receptor family and regulates brain cortical patterning. The encoded protein binds specifically to transglutaminase 2, a component of tissue and tumor stroma implicated as an inhibitor of tumor progression. Mutations in this gene are associated with a brain malformation known as bilateral frontoparietal polymicrogyria. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2014]
Verdict is Likely_pathogenic. Variant got 8 ACMG points.
PVS1
Loss of function variant, product does not undergo nonsense mediated mRNA decay. Variant located near the start codon (<100nt), not predicted to undergo nonsense mediated mRNA decay. There are 15 pathogenic variants in the truncated region.
PM2
Very rare variant in population databases, with high coverage;
PP5
Variant 16-57650297-C-T is Pathogenic according to our data. Variant chr16-57650297-C-T is described in ClinVar as [Pathogenic]. Clinvar id is 189231.Status of the report is criteria_provided_single_submitter, 1 stars.
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine
Significance: Pathogenic
Review Status: criteria provided, single submitter
Collection Method: clinical testing
The p.Gln4X variant in GPR56 has not been reported in individuals with disease or in large population studies. This nonsense variant leads to a premature termination codon at position 4, which is predicted to lead to a truncated or absent protein. Loss-of-function variants in the GPR56 gene have been associated with bilateral frontoparietal polymicrogyria (Piao 2004). In summary, this variant meets our criteria to be classified as pathogenic (http://pcpgm.partners.org/LMM). -