NM_002180.3:c.449+1G>C

Variant names:

• chr11-68908338-G-C
• rs797044802
• NM_002180.3:c.449+1G>C

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1 PM2

The NM_002180.3(IGHMBP2):​c.449+1G>C variant causes a splice donor, intron change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000274 in 1,461,132 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. 3/3 splice prediction tools predicting alterations to normal splicing. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: IGHMBP2 NM_002180.3 splice_donor, intron
• Scores: Splicing: ADA: 0.9999
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 9.22
• 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]

IGHMBP2 Gene-Disease associations (from GenCC):

• autosomal recessive distal spinal muscular atrophy 1

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: G2P, Ambry Genetics, Genomics England PanelApp, Orphanet, Labcorp Genetics (formerly Invitae)
• Charcot-Marie-Tooth disease axonal type 2S

  Inheritance: AR Classification: DEFINITIVE, STRONG, SUPPORTIVE Submitted by: Laboratory for Molecular Medicine, Orphanet, Ambry Genetics, Labcorp Genetics (formerly Invitae)
• hereditary peripheral neuropathy

  Inheritance: AR Classification: DEFINITIVE Submitted by: ClinGen

ACMG classification

Our verdict: Pathogenic. The variant received 10 ACMG points.

• PVS1: Splicing +-2 bp (donor or acceptor) variant, LoF is a know mechanism of disease, No cryptic splice site detected. Exon removal results in frameshift change.
• PM2: Very rare variant in population databases, with high coverage

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002180.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IGHMBP2	NM_002180.3	MANE Select	c.449+1G>C		splice_donor intron	N/A	NP_002171.2

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	IGHMBP2	ENST00000255078.8	TSL:1 MANE Select	c.449+1G>C		splice_donor intron	N/A	ENSP00000255078.4
	IGHMBP2	ENST00000675615.1		c.449+1G>C		splice_donor intron	N/A	ENSP00000502413.1
	IGHMBP2	ENST00000539224.2	TSL:3	n.410+1G>C		splice_donor intron	N/A	ENSP00000440465.2

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461132 Hom.: 0 Cov.: 31 AF XY: 0.00000138 AC XY: 1 AN XY: 726958

African (AFR) AF: 0.00 AC: 0 AN: 33466

American (AMR) AF: 0.00 AC: 0 AN: 44724

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86248

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53348

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000360 AC: 4 AN: 1111384

Other (OTH) AF: 0.00 AC: 0 AN: 60368

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Benign	-0.13
CADD	Pathogenic	33
DANN	Benign	0.97
Eigen	Pathogenic	0.73
Eigen_PC	Uncertain	0.50
FATHMM_MKL	Pathogenic	0.99	D
PhyloP100		9.2
GERP RS		3.2
Mutation Taster		=0/100	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
dbscSNV1_ADA	Pathogenic	1.0
dbscSNV1_RF	Pathogenic	0.91
SpliceAI score (max)		1.0		Details are displayed if max score is > 0.2
DS_DG_spliceai		0.21		Position offset: 26
DS_DL_spliceai		1.0		Position offset: -1

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

Other links and lift over

dbSNP: rs797044802; hg19: chr11-68675806;