NM_144508.5:c.4903C>G

Variant names:

• chr15-40625167-C-G
• rs1216173133
• NM_144508.5:c.4903C>G

Variant summary

Our verdict is Likely benign. The variant received -2 ACMG points: 2P and 4B. PM2 BP4_Strong

The NM_144508.5(KNL1):​c.4903C>G​(p.Leu1635Val) variant causes a missense change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000000684 in 1,461,746 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a benign outcome for this variant. 15/21 in silico tools predict a benign 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. L1635L) has been classified as Likely benign.

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: KNL1 NM_144508.5 missense
• Clinical Significance: Not reported in ClinVar
• Conservation: PhyloP100: 0.325
• Publications: 1 publications found

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

ACMG classification

Our verdict: Likely_benign. The variant received -2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• BP4: Computational evidence support a benign effect (MetaRNN=0.024549454).

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_144508.5. 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
	KNL1	NM_144508.5	MANE Select	c.4903C>G	p.Leu1635Val	missense	Exon 10 of 26	NP_653091.3
	KNL1	NM_170589.5		c.4981C>G	p.Leu1661Val	missense	Exon 11 of 27	NP_733468.3

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	KNL1	ENST00000399668.7	TSL:1 MANE Select	c.4903C>G	p.Leu1635Val	missense	Exon 10 of 26	ENSP00000382576.3
	KNL1	ENST00000346991.9	TSL:1	c.4981C>G	p.Leu1661Val	missense	Exon 11 of 27	ENSP00000335463.6
	KNL1	ENST00000526913.5	TSL:1	n.2035C>G		non_coding_transcript_exon	Exon 1 of 18	ENSP00000432565.1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD2 exomes AF: 0.00000401 AC: 1 AN: 249174 AF XY: 0.00000740

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: 0.00

Gnomad NFE exome AF: 0.00

Gnomad OTH exome AF: 0.000166

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461746 Hom.: 0 Cov.: 34 AF XY: 0.00000138 AC XY: 1 AN XY: 727170

⚠️ 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: 33478

American (AMR) AF: 0.00 AC: 0 AN: 44722

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

East Asian (EAS) AF: 0.00 AC: 0 AN: 39682

South Asian (SAS) AF: 0.00 AC: 0 AN: 86240

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53392

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

European-Non Finnish (NFE) AF: 0.00 AC: 0 AN: 1111946

Other (OTH) AF: 0.0000166 AC: 1 AN: 60388

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

Alfa AF: 0.000111 Hom.: 0

ClinVar

Not reported in ClinVar

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.065
BayesDel_addAF	Benign	-0.32	T
BayesDel_noAF	Benign	-0.69
CADD	Benign	0.47
DANN	Benign	0.34
DEOGEN2	Benign	0.016	T
Eigen	Benign	-1.6
Eigen_PC	Benign	-1.5
FATHMM_MKL	Benign	0.0016	N
LIST_S2	Benign	0.56	T
M_CAP	Benign	0.0031	T
MetaRNN	Benign	0.025	T
MetaSVM	Benign	-0.94	T
PhyloP100		0.33
PrimateAI	Benign	0.26	T
PROVEAN	Benign	0.72	N
REVEL	Benign	0.052
Sift	Benign	1.0	T
Sift4G	Benign	1.0	T
Polyphen		0.0010	B
Vest4		0.020
MutPred		0.091		Gain of methylation at K1664 (P = 0.0645)
MVP		0.081
MPC		0.038
ClinPred		0.050	T
GERP RS		0.14
Varity_R		0.027
gMVP		0.097

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: rs1216173133; hg19: chr15-40917365;