chr2-74374336-G-T

Variant names:

• chr2-74374336-G-T
• rs147939455
• NM_004082.5:c.419C>A

Variant summary

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

The NM_004082.5(DCTN1):​c.419C>A​(p.Pro140Gln) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.0000031 in 1,613,122 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. P140T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: 𝑓 0.0000066 (0 hom., cov: 32)
  • Exomes 𝑓: 0.0000027 (0 hom.)
• Consequence: DCTN1 NM_004082.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.68
• Publications: 1 publications found

Genes affected

DCTN1 (HGNC:2711): (dynactin subunit 1) This gene encodes the largest subunit of dynactin, a macromolecular complex consisting of 10 subunits ranging in size from 22 to 150 kD. Dynactin binds to both microtubules and cytoplasmic dynein. Dynactin is involved in a diverse array of cellular functions, including ER-to-Golgi transport, the centripetal movement of lysosomes and endosomes, spindle formation, chromosome movement, nuclear positioning, and axonogenesis. This subunit interacts with dynein intermediate chain by its domains directly binding to dynein and binds to microtubules via a highly conserved glycine-rich cytoskeleton-associated protein (CAP-Gly) domain in its N-terminus. Alternative splicing of this gene results in multiple transcript variants encoding distinct isoforms. Mutations in this gene cause distal hereditary motor neuronopathy type VIIB (HMN7B) which is also known as distal spinal and bulbar muscular atrophy (dSBMA). [provided by RefSeq, Oct 2008]

DCTN1 Gene-Disease associations (from GenCC):

• amyotrophic lateral sclerosis type 1

  Inheritance: AD Classification: STRONG Submitted by: Labcorp Genetics (formerly Invitae), Genomics England PanelApp
• neuronopathy, distal hereditary motor, type 7B

  Inheritance: AD Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Genomics England PanelApp, Labcorp Genetics (formerly Invitae)
• Perry syndrome

  Inheritance: AD Classification: STRONG, MODERATE, SUPPORTIVE Submitted by: Orphanet, Genomics England PanelApp, Labcorp Genetics (formerly Invitae), Ambry Genetics
• amyotrophic lateral sclerosis

  Inheritance: AD Classification: MODERATE Submitted by: ClinGen
• distal hereditary motor neuropathy type 7

  Inheritance: AD Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

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

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

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_004082.5. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	DCTN1	NM_004082.5	MANE Select	c.419C>A	p.Pro140Gln	missense	Exon 6 of 32	NP_004073.2
	DCTN1	NM_001190837.2		c.398C>A	p.Pro133Gln	missense	Exon 5 of 31	NP_001177766.1
	DCTN1	NM_001378991.1		c.368C>A	p.Pro123Gln	missense	Exon 6 of 32	NP_001365920.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	DCTN1	ENST00000628224.3	TSL:5 MANE Select	c.419C>A	p.Pro140Gln	missense	Exon 6 of 32	ENSP00000487279.2
	DCTN1	ENST00000361874.8	TSL:1	c.419C>A	p.Pro140Gln	missense	Exon 6 of 31	ENSP00000354791.4
	DCTN1	ENST00000409438.5	TSL:1	c.17C>A	p.Pro6Gln	missense	Exon 1 of 26	ENSP00000387270.1

Frequencies

GnomAD3 genomes AF: 0.00000658 AC: 1 AN: 151876 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000242

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.00

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.00

Gnomad OTH AF: 0.00

GnomAD4 exome AF: 0.00000274 AC: 4 AN: 1461246 Hom.: 0 Cov.: 33 AF XY: 0.00000275 AC XY: 2 AN XY: 726922

African (AFR) AF: 0.0000896 AC: 3 AN: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44692

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26130

East Asian (EAS) AF: 0.00 AC: 0 AN: 39674

South Asian (SAS) AF: 0.0000116 AC: 1 AN: 86198

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53324

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5762

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111646

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

GnomAD4 genome AF: 0.00000658 AC: 1 AN: 151876 Hom.: 0 Cov.: 32 AF XY: 0.00 AC XY: 0 AN XY: 74208

African (AFR) AF: 0.0000242 AC: 1 AN: 41310

American (AMR) AF: 0.00 AC: 0 AN: 15256

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3472

East Asian (EAS) AF: 0.00 AC: 0 AN: 5176

South Asian (SAS) AF: 0.00 AC: 0 AN: 4800

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 10580

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 316

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 67972

Other (OTH) AF: 0.00 AC: 0 AN: 2084

Alfa AF: 0.00 Hom.: 0

Bravo AF: 0.00000756

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Neuronopathy, distal hereditary motor, type 7B;C1862939:Amyotrophic lateral sclerosis type 1;C1868594:Perry syndrome Uncertain:1

Nov 03, 2022

Labcorp Genetics (formerly Invitae), Labcorp

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has not been reported in the literature in individuals affected with DCTN1-related conditions. Algorithms developed to predict the effect of missense changes on protein structure and function (SIFT, PolyPhen-2, Align-GVGD) all suggest that this variant is likely to be tolerated. Algorithms developed to predict the effect of sequence changes on RNA splicing suggest that this variant may disrupt the consensus splice site. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. This variant is not present in population databases (gnomAD no frequency). This sequence change replaces proline, which is neutral and non-polar, with glutamine, which is neutral and polar, at codon 140 of the DCTN1 protein (p.Pro140Gln).

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.12
BayesDel_addAF	Pathogenic	0.21	D
BayesDel_noAF	Uncertain	0.060
CADD	Pathogenic	26
DANN	Benign	0.95
DEOGEN2	Benign	0.092	T
Eigen	Uncertain	0.37
Eigen_PC	Uncertain	0.44
FATHMM_MKL	Uncertain	0.97	D
LIST_S2	Benign	0.72	T
M_CAP	Uncertain	0.13	D
MetaRNN	Benign	0.34	T
MetaSVM	Uncertain	-0.20	T
MutationAssessor	Benign	1.4	L
PhyloP100		7.7
PrimateAI	Uncertain	0.61	T
PROVEAN	Benign	-0.27	N
REVEL	Uncertain	0.31
Sift	Benign	0.056	T
Sift4G	Benign	0.14	T
Polyphen		1.0	D
Vest4		0.58
MutPred		0.21		Loss of glycosylation at P140 (P = 0.012)
MVP		0.74
MPC		0.59
ClinPred		0.92	D
GERP RS		4.3
PromoterAI		-0.057	Neutral
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.6
Varity_R		0.17
gMVP		0.31
Mutation Taster		=66/34	polymorphism

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.21		Details are displayed if max score is > 0.2
DS_AL_spliceai		0.21		Position offset: 4

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs147939455; hg19: chr2-74601463; COSMIC: COSV62621321; COSMIC: COSV62621321;