11-68903998-C-T

Variant names:

• chr11-68903998-C-T
• rs1334447515
• NM_002180.3:c.46C>T

Variant summary

Our verdict is Likely benign. The variant received -5 ACMG points: 2P and 7B. PM2 BP4_Strong BP6_Moderate BP7

The NM_002180.3(IGHMBP2):​c.46C>T​(p.Leu16Leu) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000715 in 1,398,962 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: not found (cov: 35)
  • Exomes 𝑓: 7.1e-7 (0 hom.)
• Consequence: IGHMBP2 NM_002180.3 synonymous
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: 2.49
• Publications: 0 publications found

Genes affected

IGHMBP2 (HGNC:5542): (immunoglobulin mu DNA binding protein 2) This gene encodes a helicase superfamily member that binds a specific DNA sequence from the immunoglobulin mu chain switch region. Mutations in this gene lead to spinal muscle atrophy with respiratory distress type 1. [provided by RefSeq, Jul 2008]

MRPL21 (HGNC:14479): (mitochondrial ribosomal protein L21) Mammalian mitochondrial ribosomal proteins are encoded by nuclear genes and help in protein synthesis within the mitochondrion. Mitochondrial ribosomes (mitoribosomes) consist of a small 28S subunit and a large 39S subunit. They have an estimated 75% protein to rRNA composition compared to prokaryotic ribosomes, where this ratio is reversed. Another difference between mammalian mitoribosomes and prokaryotic ribosomes is that the latter contain a 5S rRNA. Among different species, the proteins comprising the mitoribosome differ greatly in sequence, and sometimes in biochemical properties, which prevents easy recognition by sequence homology. This gene encodes a 39S subunit protein. Multiple transcript variants encoding different isoforms were identified through sequence analysis although some may be subject to nonsense-mediated decay (NMD). [provided by RefSeq, Jul 2008]

ACMG classification

Our verdict: Likely_benign. The variant received -5 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.55).
• BP6: Variant 11-68903998-C-T is Benign according to our data. Variant chr11-68903998-C-T is described in ClinVar as [Likely_benign]. Clinvar id is 2937689.Status of the report is criteria_provided_single_submitter, 1 stars.
• BP7: Synonymous conserved (PhyloP=2.49 with no splicing effect.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
IGHMBP2	NM_002180.3	c.46C>T	p.Leu16Leu	synonymous_variant	Exon 1 of 15	ENST00000255078.8	NP_002171.2
MRPL21	NM_181514.2	c.-188G>A		upstream_gene_variant		ENST00000362034.7	NP_852615.1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
IGHMBP2	ENST00000255078.8	c.46C>T	p.Leu16Leu	synonymous_variant	Exon 1 of 15	1	NM_002180.3	ENSP00000255078.4
MRPL21	ENST00000362034.7	c.-188G>A		upstream_gene_variant		1	NM_181514.2	ENSP00000354580.2

Frequencies

GnomAD3 genomes Cov.: 35

GnomAD4 exome AF: 7.15e-7 AC: 1 AN: 1398962 Hom.: 0 Cov.: 44 AF XY: 0.00000145 AC XY: 1 AN XY: 690246

African (AFR) AF: 0.00 AC: 0 AN: 31602

American (AMR) AF: 0.00 AC: 0 AN: 35730

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25164

East Asian (EAS) AF: 0.00 AC: 0 AN: 35762

South Asian (SAS) AF: 0.00 AC: 0 AN: 79600

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 48198

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5678

European-Non Finnish (NFE) AF: 9.27e-7 AC: 1 AN: 1079214

Other (OTH) AF: 0.00 AC: 0 AN: 58014

GnomAD4 genome Cov.: 35

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

Autosomal recessive distal spinal muscular atrophy 1;C4015349:Charcot-Marie-Tooth disease axonal type 2S Benign:1

May 18, 2023

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.55
CADD	Benign	15
DANN	Benign	0.97
PhyloP100		2.5
PromoterAI		0.037	Neutral

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.0		Details are displayed if max score is > 0.2

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

Other links and lift over

dbSNP: rs1334447515; hg19: chr11-68671466;