9-70126278-C-T

Variant names:

• chr9-70126278-C-T
• rs148363356
• NM_153267.5:c.763C>T

Variant summary

Our verdict is Uncertain significance. The variant received 2 ACMG points: 2P and 0B. PM2

The NM_153267.5(MAMDC2):​c.763C>T​(p.Gln255*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,882 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. No clinical diagnostic laboratories have submitted clinical-significance assessments for this variant to ClinVar. Variant results in nonsense mediated mRNA decay.

• Frequency:
  • Genomes: not found (cov: 31)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: MAMDC2 NM_153267.5 stop_gained
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 2.76
• Publications: 0 publications found

Genes affected

MAMDC2 (HGNC:23673): (MAM domain containing 2) Predicted to enable glycosaminoglycan binding activity. Predicted to act upstream of or within peptide cross-linking via chondroitin 4-sulfate glycosaminoglycan. Located in endoplasmic reticulum. [provided by Alliance of Genome Resources, Apr 2022]

MAMDC2-AS1 (HGNC:48719): (MAMDC2 antisense RNA 1)

ACMG classification

Our verdict: Uncertain_significance. The variant received 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
MAMDC2	NM_153267.5	c.763C>T	p.Gln255*	stop_gained	Exon 6 of 14	ENST00000377182.5	NP_694999.3
MAMDC2	NM_001347990.2	c.763C>T	p.Gln255*	stop_gained	Exon 6 of 12		NP_001334919.1
MAMDC2	NR_125850.1	n.1380C>T		non_coding_transcript_exon_variant	Exon 6 of 14

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
MAMDC2	ENST00000377182.5	c.763C>T	p.Gln255*	stop_gained	Exon 6 of 14	1	NM_153267.5	ENSP00000366387.4

Frequencies

GnomAD3 genomes Cov.: 31

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461882 Hom.: 0 Cov.: 42 AF XY: 0.00 AC XY: 0 AN XY: 727240

⚠️ 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: 33480

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

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26136

East Asian (EAS) AF: 0.00 AC: 0 AN: 39698

South Asian (SAS) AF: 0.00 AC: 0 AN: 86258

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53420

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5768

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1112002

Other (OTH) AF: 0.00 AC: 0 AN: 60396

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000000), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 31

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.60	D
BayesDel_noAF	Pathogenic	0.62
CADD	Pathogenic	37
DANN	Uncertain	1.0
Eigen	Uncertain	0.64
Eigen_PC	Uncertain	0.46
FATHMM_MKL	Uncertain	0.93	D
PhyloP100		2.8
Vest4		0.43
GERP RS		4.2
Mutation Taster		=7/193	disease causing (fs/PTC)

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: rs148363356; hg19: chr9-72741194;