chr16-25132414-G-A

Position:

• chr16-25132414-G-A

Variant summary

Our verdict is Likely pathogenic. Variant got 8 ACMG points: 8P and 0B. PM1 PM2 PP3_Strong

The ENST00000399069.8(LCMT1):​c.218G>A​(p.Arg73Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,482 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: LCMT1 ENST00000399069.8 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 9.30

Genes affected

LCMT1 (HGNC:17557): (leucine carboxyl methyltransferase 1) LCMT1 catalyzes the methylation of the carboxyl group of the C-terminal leucine residue (leu309) of the catalytic subunit of protein phosphatase-2A (PPP2CA; MIM 176915) (De Baere et al., 1999 [PubMed 10600115]).[supplied by OMIM, Mar 2008]

ACMG classification

Verdict is Likely_pathogenic. Variant got 8 ACMG points.

• PM1: In a binding_site (size 0) in uniprot entity LCMT1_HUMAN
• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.977

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
LCMT1	NM_016309.3	c.218G>A	p.Arg73Gln	missense_variant	3/11	ENST00000399069.8	NP_057393.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
LCMT1	ENST00000399069.8	c.218G>A	p.Arg73Gln	missense_variant	3/11	1	NM_016309.3	ENSP00000382021	P1

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461482 Hom.: 0 Cov.: 31 AF XY: 0.00 AC XY: 0 AN XY: 727044

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 31

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Ambry Genetics

Jan 23, 2024

The c.218G>A (p.R73Q) alteration is located in exon 3 (coding exon 3) of the LCMT1 gene. This alteration results from a G to A substitution at nucleotide position 218, causing the arginine (R) at amino acid position 73 to be replaced by a glutamine (Q). Based on insufficient or conflicting evidence, the clinical significance of this alteration remains unclear. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.98
BayesDel_addAF	Pathogenic	0.35	D
BayesDel_noAF	Pathogenic	0.26
CADD	Pathogenic	32
DANN	Pathogenic	1.0
DEOGEN2	Uncertain	0.48	T;.;.
Eigen	Pathogenic	0.87
Eigen_PC	Pathogenic	0.75
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Pathogenic	0.99	D;D;D
M_CAP	Uncertain	0.15	D
MetaRNN	Pathogenic	0.98	D;D;D
MetaSVM	Uncertain	0.016	D
MutationAssessor	Pathogenic	4.0	H;H;.
MutationTaster	Benign	1.0	D;D
PrimateAI	Uncertain	0.54	T
PROVEAN	Uncertain	-3.9	D;D;.
REVEL	Uncertain	0.50
Sift	Pathogenic	0.0	D;D;.
Sift4G	Uncertain	0.0040	D;D;D
Polyphen		1.0	D;D;.
Vest4		0.97
MutPred		0.96		Loss of methylation at R73 (P = 0.0244);Loss of methylation at R73 (P = 0.0244);.;
MVP		0.79
MPC		0.96
ClinPred		1.0	D
GERP RS		3.5
Varity_R		0.91
gMVP		0.93

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

Publications

LitVar

Other links and lift over

dbSNP: rs995675568; hg19: chr16-25143735; COSMIC: COSV66725785;