18-77026349-A-G

Position:

• chr18-77026349-A-G

Variant summary

Our verdict is Benign. Variant got -12 ACMG points: 0P and 12B. BP4_Strong BA1

The NM_001025101.2(MBP):​c.140-9081T>C variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.681 in 152,168 control chromosomes in the GnomAD database, including 35,456 homozygotes. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency: Genomes: 𝑓 0.68 (35456 hom., cov: 33)
• Consequence: MBP NM_001025101.2 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -0.576

Genes affected

MBP (HGNC:6925): (myelin basic protein) The protein encoded by the classic MBP gene is a major constituent of the myelin sheath of oligodendrocytes and Schwann cells in the nervous system. However, MBP-related transcripts are also present in the bone marrow and the immune system. These mRNAs arise from the long MBP gene (otherwise called "Golli-MBP") that contains 3 additional exons located upstream of the classic MBP exons. Alternative splicing from the Golli and the MBP transcription start sites gives rise to 2 sets of MBP-related transcripts and gene products. The Golli mRNAs contain 3 exons unique to Golli-MBP, spliced in-frame to 1 or more MBP exons. They encode hybrid proteins that have N-terminal Golli aa sequence linked to MBP aa sequence. The second family of transcripts contain only MBP exons and produce the well characterized myelin basic proteins. This complex gene structure is conserved among species suggesting that the MBP transcription unit is an integral part of the Golli transcription unit and that this arrangement is important for the function and/or regulation of these genes. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Benign. Variant got -12 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-1.0).
• BA1: GnomAd4 highest subpopulation (EAS) allele frequency at 95% confidence interval = 0.785 is higher than 0.05.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
MBP	NM_001025101.2	c.140-9081T>C		intron_variant		ENST00000355994.7

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
MBP	ENST00000355994.7	c.140-9081T>C		intron_variant		5	NM_001025101.2	P1

Frequencies

GnomAD3 genomes AF: 0.681 AC: 103478 AN: 152048 Hom.: 35437 Cov.: 33

Gnomad AFR AF: 0.710

Gnomad AMI AF: 0.671

Gnomad AMR AF: 0.699

Gnomad ASJ AF: 0.611

Gnomad EAS AF: 0.806

Gnomad SAS AF: 0.648

Gnomad FIN AF: 0.677

Gnomad MID AF: 0.642

Gnomad NFE AF: 0.656

Gnomad OTH AF: 0.675

We have no GnomAD4 exomes data on this position. Probably position not covered by the project.

GnomAD4 genome AF: 0.681 AC: 103553 AN: 152168 Hom.: 35456 Cov.: 33 AF XY: 0.683 AC XY: 50823 AN XY: 74390

Gnomad4 AFR AF: 0.710

Gnomad4 AMR AF: 0.699

Gnomad4 ASJ AF: 0.611

Gnomad4 EAS AF: 0.805

Gnomad4 SAS AF: 0.649

Gnomad4 FIN AF: 0.677

Gnomad4 NFE AF: 0.656

Gnomad4 OTH AF: 0.675

Alfa AF: 0.669 Hom.: 9093

Bravo AF: 0.685

Asia WGS AF: 0.714 AC: 2482 AN: 3478

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-1.0
CADD	Benign	0.75
DANN	Benign	0.25

Splicing

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Publications

LitVar

Other links and lift over

dbSNP: rs2282574; hg19: chr18-74738305;