2-137971543-G-T

Variant names:

• chr2-137971543-G-T
• rs1982494
• NM_006895.3:c.190+1326G>T

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_006895.3(HNMT):​c.190+1326G>T variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. 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: not found (cov: 31)
• Consequence: HNMT NM_006895.3 intron
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.318
• Publications: 2 publications found

Genes affected

HNMT (HGNC:5028): (histamine N-methyltransferase) In mammals, histamine is metabolized by two major pathways: N(tau)-methylation via histamine N-methyltransferase and oxidative deamination via diamine oxidase. This gene encodes the first enzyme which is found in the cytosol and uses S-adenosyl-L-methionine as the methyl donor. In the mammalian brain, the neurotransmitter activity of histamine is controlled by N(tau)-methylation as diamine oxidase is not found in the central nervous system. A common genetic polymorphism affects the activity levels of this gene product in red blood cells. Multiple alternatively spliced transcript variants that encode different proteins have been found for this gene. [provided by RefSeq, Jul 2008]

HNMT Gene-Disease associations (from GenCC):

• intellectual disability, autosomal recessive 51

  Inheritance: AR Classification: STRONG, LIMITED Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
• autosomal recessive non-syndromic intellectual disability

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.79).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_006895.3. 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
	HNMT	NM_006895.3	MANE Select	c.190+1326G>T		intron	N/A	NP_008826.1
	HNMT	NM_001024075.3		c.190+1326G>T		intron	N/A	NP_001019246.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	HNMT	ENST00000280097.5	TSL:1 MANE Select	c.190+1326G>T		intron	N/A	ENSP00000280097.3
	HNMT	ENST00000329366.8	TSL:1	c.190+1326G>T		intron	N/A	ENSP00000333259.4
	HNMT	ENST00000410115.5	TSL:5	c.190+1326G>T		intron	N/A	ENSP00000386940.1

Frequencies

GnomAD3 genomes Cov.: 31

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

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	1.4
DANN	Benign	0.78
PhyloP100		0.32

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: rs1982494; hg19: chr2-138729113;