NM_002299.4:c.653_654delCT

Variant names:

• chr2-135833176-CAG-C
• rs386833838
• NM_002299.4:c.653_654delCT

Variant summary

Our verdict is Pathogenic. The variant received 11 ACMG points: 11P and 0B. PVS1 PM2 PP5

The NM_002299.4(LCT):​c.653_654delCT​(p.Ser218CysfsTer6) variant causes a frameshift change. The variant allele was found at a frequency of 0.000000684 in 1,461,702 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Likely pathogenic (no stars). Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 29)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LCT NM_002299.4 frameshift
• Clinical Significance: Likely pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 4.82
• Publications: 6 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: Orphanet, Labcorp Genetics (formerly Invitae), PanelApp Australia, Ambry Genetics

ACMG classification

Our verdict: Pathogenic. The variant received 11 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 2-135833176-CAG-C is Pathogenic according to our data. Variant chr2-135833176-CAG-C is described in ClinVar as Likely_pathogenic. ClinVar VariationId is 56393.Status of the report is no_assertion_criteria_provided, 0 stars.

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.653_654delCT	p.Ser218CysfsTer6	frameshift	Exon 2 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.653_654delCT	p.Ser218CysfsTer6	frameshift	Exon 2 of 17	ENSP00000264162.2

Frequencies

GnomAD3 genomes Cov.: 29

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461702 Hom.: 0 AF XY: 0.00000138 AC XY: 1 AN XY: 727164

African (AFR) AF: 0.00 AC: 0 AN: 33474

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39700

South Asian (SAS) AF: 0.00 AC: 0 AN: 86252

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53418

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5764

European-Non Finnish (NFE) AF: 8.99e-7 AC: 1 AN: 1111852

Other (OTH) AF: 0.00 AC: 0 AN: 60386

GnomAD4 genome Cov.: 29

ClinVar

ClinVar submissions as Germline

Significance: Likely pathogenic

Revision: no assertion criteria provided

Pathogenic	VUS	Benign	Condition
1	-	-	Congenital lactase deficiency (1)

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
PhyloP100		4.8
Mutation Taster		=3/197	disease causing (ClinVar)

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: rs386833838; hg19: chr2-136590746;