2-135822027-T-A

Variant names:

• chr2-135822027-T-A
• NM_002299.4:c.979A>T

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PVS1 PM2 PP5_Moderate

The NM_002299.4(LCT):​c.979A>T​(p.Lys327*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Variant results in nonsense mediated mRNA decay.

• Frequency: Genomes: not found (cov: 33)
• Consequence: LCT NM_002299.4 stop_gained
• Clinical Significance: Pathogenic criteria provided, single submitter P:1
• Conservation: PhyloP100: 0.437

Genes affected

LCT (HGNC:6530): (lactase) The protein encoded by this gene belongs to the glycosyl hydrolase 1 family of proteins. The encoded preproprotein is proteolytically processed to generate the mature enzyme. This enzyme is integral to the plasma membrane and has both phlorizin hydrolase activity and lactase activity. Mutations in this gene are associated with congenital lactase deficiency. Polymorphisms in this gene are associated with lactase persistence, in which intestinal lactase activity persists at childhood levels into adulthood. [provided by RefSeq, Jan 2016]

LCT-AS1 (HGNC:40337): (LCT antisense RNA 1)

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PVS1: Loss of function variant, product undergoes nonsense mediated mRNA decay. LoF is a known mechanism of disease.
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 2-135822027-T-A is Pathogenic according to our data. Variant chr2-135822027-T-A is described in ClinVar as [Pathogenic]. Clinvar id is 3639526.Status of the report is criteria_provided_single_submitter, 1 stars.

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
LCT	NM_002299.4	c.979A>T	p.Lys327*	stop_gained	Exon 5 of 17	ENST00000264162.7	NP_002290.2
LCT	XM_017004088.3	c.979A>T	p.Lys327*	stop_gained	Exon 5 of 15		XP_016859577.1
LCT-AS1	NR_045486.1	n.802T>A		non_coding_transcript_exon_variant	Exon 2 of 2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
LCT	ENST00000264162.7	c.979A>T	p.Lys327*	stop_gained	Exon 5 of 17	1	NM_002299.4	ENSP00000264162.2
LCT-AS1	ENST00000437007.1	n.802T>A		non_coding_transcript_exon_variant	Exon 2 of 2	2

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome Cov.: 26

GnomAD4 genome Cov.: 33

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1

Feb 07, 2024

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This sequence change creates a premature translational stop signal (p.Lys327*) in the LCT gene. It is expected to result in an absent or disrupted protein product. Loss-of-function variants in LCT are known to be pathogenic (PMID: 16400612, 25881162). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with LCT-related conditions. For these reasons, this variant has been classified as Pathogenic. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.63	D
BayesDel_noAF	Pathogenic	0.38
CADD	Pathogenic	33
DANN	Uncertain	0.99
Eigen	Benign	0.16
Eigen_PC	Benign	-0.11
FATHMM_MKL	Benign	0.18	N
Vest4		0.69
GERP RS		2.0

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.11		Details are displayed if max score is > 0.2

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr2-136579597;