Genetic Variant KNL1:p.Cys1757* (chr15-40625535-C-A) – ACMG Classification: Pathogenic (10 pts)

Variant summary

Our verdict is Pathogenic. The variant received 10 ACMG points: 10P and 0B. PVS1PM2

The NM_144508.5(KNL1):c.5271C>A(p.Cys1757*) variant causes a stop gained change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000687 in 1,455,652 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. Synonymous variant affecting the same amino acid position (i.e. C1757C) has been classified as Likely benign. Variant results in nonsense mediated mRNA decay.

Frequency

Genomes: not found (cov: 32)

Exomes 𝑓: 6.9e-7 ( 0 hom. )

Consequence

KNL1
NM_144508.5 stop_gained

Scores

Clinical Significance

Not reported in ClinVar

Conservation

PhyloP100: -0.167

Publications

0 publications found

Variant links:

Genes affected

KNL1 (HGNC:24054): (kinetochore scaffold 1) The protein encoded by this gene is a component of the multiprotein assembly that is required for creation of kinetochore-microtubule attachments and chromosome segregation. The encoded protein functions as a scaffold for proteins that influence the spindle assembly checkpoint during the eukaryotic cell cycle and it interacts with at least five different kinetochore proteins and two checkpoint kinases. In adults, this gene is predominantly expressed in normal testes, various cancer cell lines and primary tumors from other tissues and is ubiquitously expressed in fetal tissues. This gene was originally identified as a fusion partner with the mixed-lineage leukemia (MLL) gene in t(11;15)(q23;q14). Mutations in this gene cause autosomal recessive primary microcephaly-4 (MCPH4). Alternative splicing results in multiple transcript variants encoding different isoforms. Additional splice variants have been described but their biological validity has not been confirmed. [provided by RefSeq, Jan 2013]

KNL1 Gene-Disease associations (from GenCC):

microcephaly 4, primary, autosomal recessive
Inheritance: AR Classification: STRONG, MODERATE Submitted by: Ambry Genetics, Labcorp Genetics (formerly Invitae)
autosomal recessive primary microcephaly
Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

KNL1 links:

Genome browser will be placed here

ACMG classification

Classification was made for transcript

Our verdict: Pathogenic. The variant received 10 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;

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KNL1	NM_144508.5 link	c.5271C>A	p.Cys1757*	stop_gained	Exon 10 of 26	ENST00000399668.7	NP_653091.3	Q8NG31-2
KNL1	NM_170589.5 link	c.5349C>A	p.Cys1783*	stop_gained	Exon 11 of 27		NP_733468.3	Q8NG31-1

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KNL1	ENST00000399668.7 link	c.5271C>A	p.Cys1757*	stop_gained	Exon 10 of 26	1	NM_144508.5	ENSP00000382576.3		Q8NG31-2

Frequencies

GnomAD3 genomes

Cov.:

GnomAD2 exomes

AF:

0.00000412

AC:

AN:

242774

AF XY:

0.00000758

show subpopulations

Gnomad AFR exome

AF:

0.00

Gnomad AMR exome

AF:

0.00

Gnomad ASJ exome

AF:

0.00

Gnomad EAS exome

AF:

0.00

Gnomad FIN exome

AF:

0.0000466

Gnomad NFE exome

AF:

0.00

Gnomad OTH exome

AF:

0.00

GnomAD4 exome

AF:

6.87e-7

AC:

AN:

1455652

Hom.:

Cov.:

AF XY:

0.00000138

AC XY:

AN XY:

724198

show subpopulations

African (AFR)

AF:

0.00

AC:

AN:

32778

American (AMR)

AF:

0.00

AC:

AN:

42770

Ashkenazi Jewish (ASJ)

AF:

0.00

AC:

AN:

25894

East Asian (EAS)

AF:

0.00

AC:

AN:

39650

South Asian (SAS)

AF:

0.00

AC:

AN:

84990

European-Finnish (FIN)

AF:

0.0000188

AC:

AN:

53308

Middle Eastern (MID)

AF:

0.00

AC:

AN:

5726

European-Non Finnish (NFE)

AF:

0.00

AC:

AN:

1110464

Other (OTH)

AF:

0.00

AC:

AN:

60072

Allele Balance Distribution

Red line indicates average allele balance

Average allele balance: 0.475

Heterozygous variant carriers

0.00

0.20

0.40

0.60

0.80

0.95

Allele balance

Age Distribution

Exome Het

Variant carriers

<30

30-35

35-40

40-45

45-50

50-55

55-60

60-65

65-70

70-75

75-80

>80

Age

GnomAD4 genome

Cov.:

ExAC

AF:

0.00000828

AC:

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.3

Name

Calibrated prediction

Score

Prediction

BayesDel_addAF

Pathogenic

0.62

BayesDel_noAF

Pathogenic

0.27

CADD

Uncertain

(source)

DANN

Benign

0.94

Eigen

Benign

-0.15

Eigen_PC

Benign

-0.46

FATHMM_MKL

Benign

0.066

PhyloP100

-0.17

Vest4

0.81

GERP RS

2.8

Mutation Taster

=11/189

disease causing (fs/PTC)

(source)

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

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Variant summary

Frequency

Consequence

Scores

Clinical Significance

Conservation

Publications

ACMG classification

Transcripts

RefSeq

Ensembl

Frequencies

Age Distribution

ClinVar

Computational scores

Splicing

Publications

Other links and lift over