chr18-2666927-T-C

Position:

• chr18-2666927-T-C

Variant summary

Our verdict is Likely pathogenic. Variant got 6 ACMG points: 6P and 0B. PM2 PP2 PP3_Moderate PP5

The NM_015295.3(SMCHD1):​c.320T>C​(p.Leu107Pro) variant causes a missense change involving the alteration of a 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 (no stars).

• Frequency: Genomes: not found (cov: 32)
• Consequence: SMCHD1 NM_015295.3 missense
• Clinical Significance: Pathogenic no assertion criteria provided P:1
• Conservation: PhyloP100: 7.63

Genes affected

SMCHD1 (HGNC:29090): (structural maintenance of chromosomes flexible hinge domain containing 1) This gene encodes a protein which contains a hinge region domain found in members of the SMC (structural maintenance of chromosomes) protein family. [provided by RefSeq, Dec 2011]

ACMG classification

Verdict is Likely_pathogenic. Variant got 6 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP2: Missense variant in gene, where missense usually causes diseases (based on misZ statistic), SMCHD1. . Gene score misZ: 3.6318 (greater than the threshold 3.09). Trascript score misZ: 3.965 (greater than threshold 3.09). The gene has 23 curated pathogenic missense variants (we use a threshold of 10). The gene has 10 curated benign missense variants. GenCC has associacion of the gene with facioscapulohumeral muscular dystrophy, arhinia, choanal atresia, and microphthalmia, hyposmia-nasal and ocular hypoplasia-hypogonadotropic hypogonadism syndrome.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.931
• PP5: Variant 18-2666927-T-C is Pathogenic according to our data. Variant chr18-2666927-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 431461.Status of the report is no_assertion_criteria_provided, 0 stars. Variant chr18-2666927-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	Protein	UniProt
SMCHD1	NM_015295.3	c.320T>C	p.Leu107Pro	missense_variant	3/48	ENST00000320876.11	NP_056110.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Protein	Appris	UniProt
SMCHD1	ENST00000320876.11	c.320T>C	p.Leu107Pro	missense_variant	3/48	5	NM_015295.3	ENSP00000326603.7
SMCHD1	ENST00000688342.1	c.320T>C	p.Leu107Pro	missense_variant	3/47			ENSP00000508422.1
SMCHD1	ENST00000684915.1	n.477T>C		non_coding_transcript_exon_variant	3/14

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 30

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:1

Revision: no assertion criteria provided

Submissions by phenotype

Arrhinia with choanal atresia and microphthalmia syndrome Pathogenic:1

Pathogenic, no assertion criteria provided

research

MGH Harvard Center for Reproductive Medicine, Massachusetts General Hospital

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Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.96
BayesDel_addAF	Pathogenic	0.25	D
BayesDel_noAF	Uncertain	0.13
CADD	Uncertain	25
DANN	Uncertain	1.0
DEOGEN2	Benign	0.31	T
Eigen	Uncertain	0.38
Eigen_PC	Uncertain	0.30
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Benign	0.78	T
M_CAP	Uncertain	0.17	D
MetaRNN	Pathogenic	0.93	D
MetaSVM	Benign	-0.84	T
MutationAssessor	Uncertain	2.2	M
PrimateAI	Uncertain	0.73	T
PROVEAN	Uncertain	-2.8	D
REVEL	Uncertain	0.44
Sift	Uncertain	0.018	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.96
MutPred		0.67		Loss of helix (P = 3e-04);
MVP		0.41
MPC		2.1
ClinPred		0.96	D
GERP RS		5.6
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.1
Varity_R		0.85
gMVP		0.98

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: rs1135402737; hg19: chr18-2666926;