2-135788339-C-A

Variant names:

• chr2-135788339-C-A
• rs373237484
• NM_002299.4:c.5769G>T

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PM2 BP4_Strong BP7

The NM_002299.4(LCT):​c.5769G>T​(p.Pro1923Pro) variant causes a synonymous change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000685 in 1,460,806 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Synonymous variant affecting the same amino acid position (i.e. P1923P) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LCT NM_002299.4 synonymous
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: -3.22
• Publications: 0 publications found

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 Gene-Disease associations (from GenCC):

• congenital lactase deficiency

  Inheritance: AR Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: PanelApp Australia, Ambry Genetics, Orphanet, Labcorp Genetics (formerly Invitae)

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.73).
• BP7: Synonymous conserved (PhyloP=-3.22 with no splicing effect.

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_002299.4. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LCT	NM_002299.4	MANE Select	c.5769G>T	p.Pro1923Pro	synonymous	Exon 17 of 17	NP_002290.2

Ensembl Transcripts

Sel.	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	LCT	ENST00000264162.7	TSL:1 MANE Select	c.5769G>T	p.Pro1923Pro	synonymous	Exon 17 of 17	ENSP00000264162.2	P09848

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.85e-7 AC: 1 AN: 1460806 Hom.: 0 Cov.: 34 AF XY: 0.00 AC XY: 0 AN XY: 726796

⚠️ The allele balance in gnomAD version 4 Exomes is significantly skewed from the expected value of 0.5.

African (AFR) AF: 0.00 AC: 0 AN: 33454

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26134

East Asian (EAS) AF: 0.00 AC: 0 AN: 39696

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86230

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53170

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5682

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111368

Other (OTH) AF: 0.00 AC: 0 AN: 60348

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 33

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.73
CADD	Benign	0.032
DANN	Benign	0.63
PhyloP100		-3.2
Mutation Taster		=100/0	polymorphism

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: rs373237484; hg19: chr2-136545909;