rs373957300
Variant summary
Our verdict is Uncertain significance. Variant got 5 ACMG points: 5P and 0B. PM2PP3_ModeratePP5
The NM_001519.4(BRF1):βc.776C>Tβ(p.Thr259Met) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000105 in 1,613,762 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 13/20 in silico tools predict a damaging outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars).
Frequency
Consequence
NM_001519.4 missense
Scores
Clinical Significance
Conservation
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ACMG classification
Verdict is Uncertain_significance. Variant got 5 ACMG points.
Transcripts
RefSeq
Ensembl
Frequencies
GnomAD3 genomes AF: 0.0000263 AC: 4AN: 152218Hom.: 0 Cov.: 33
GnomAD3 exomes AF: 0.0000159 AC: 4AN: 251300Hom.: 0 AF XY: 0.00000736 AC XY: 1AN XY: 135810
GnomAD4 exome AF: 0.00000889 AC: 13AN: 1461544Hom.: 0 Cov.: 31 AF XY: 0.00000550 AC XY: 4AN XY: 727050
GnomAD4 genome AF: 0.0000263 AC: 4AN: 152218Hom.: 0 Cov.: 33 AF XY: 0.0000269 AC XY: 2AN XY: 74366
ClinVar
Submissions by phenotype
Cerebellar-facial-dental syndrome Pathogenic:3
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The p.Thr259Met variant was found in a research study in a compound heterozygous state with the variant c.793_794delACinsCATTTA, p.Thr265HisfsX5 (T265HfsX5). The six year old female displayed failure to thrive, microcephaly, dysmorphic facial features, short stature, global developmental delays, anemia, osteopenia, hypotonia, seizures, cerebellar ataxia, sensorineural hearing loss and a bicuspid aortic valve. Bilateral progressive fetal nuclear cataracts with a cortical radial Γ’β¬ΕriderΓ’β¬Β and numerous vacuoles were also seen. The p.Thr259Met variant was previously described in affected siblings in a compound heterozygous state by Borck et al. (2015). -
Inborn genetic diseases Pathogenic:1
The c.776C>T (p.T259M) alteration is located in coding exon 7 of the BRF1 gene. This alteration results from a C to T substitution at nucleotide position 776, causing the threonine (T) at amino acid position 259 to be replaced by a methionine (M). Based on data from the Genome Aggregation Database (gnomAD) database, the BRF1 c.776C>T alteration was observed in 0.0021% (6/282678) of total alleles studied, with a frequency of 0.012% (3/25070) in the European (Finnish) subpopulation. This alteration was observed to occur in trans with another missense variant in two individuals from one family who presented with clinical features of cerebrofaciodental syndrome including microcephaly, short stature, mild intellectual disability, facial dysmorphism, dental anomalies, scoliosis, delayed bone age, cardiac anomalies, and brain anomalies (Borck, 2015). The p.T259 amino acid is conserved in available vertebrate species. Yeast cells with the p.T259M alteration were observed to decrease promoter binding of Pol III at several tRNA sites and decrease transcription output as compared to yeast with wildtype protein (Borck, 2015). The p.T259M alteration is predicted to be deleterious by in silico analysis. Based on the available evidence, this alteration is classified as likely pathogenic. -
not provided Uncertain:1
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. Experimental studies in zebrafish, yeast and in vitro have shown that this missense change partially disrupts BRF1 protein function (PMID: 25561519). This variant has been reported to segregate with short stature, microcephaly, intellectual disability and characteristic facial dysmorphology in a single family (PMID: 25561519). ClinVar contains an entry for this variant (Variation ID: 161424). This variant is present in population databases (rs373957300, ExAC 0.003%). This sequence change replaces threonine with methionine at codon 259 of the BRF1 protein (p.Thr259Met). The threonine residue is highly conserved and there is a moderate physicochemical difference between threonine and methionine. -
Computational scores
Source:
Splicing
Find out detailed SpliceAI scores and Pangolin per-transcript scores at