NM_144508.5:c.36-136A>G

Variant names:

• chr15-40604974-A-G
• rs115347081
• NM_144508.5:c.36-136A>G

Variant summary

Our verdict is Benign. The variant received -14 ACMG points: 0P and 14B. BP4_Strong BP6_Moderate BS1 BS2

The NM_144508.5(KNL1):​c.36-136A>G variant causes a intron change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.00468 in 587,684 control chromosomes in the GnomAD database, including 63 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Likely benign (★).

• Frequency:
  • Genomes: 𝑓 0.013 (41 hom., cov: 32)
  • Exomes 𝑓: 0.0019 (22 hom.)
• Consequence: KNL1 NM_144508.5 intron
• Clinical Significance: Likely benign criteria provided, single submitter B:1
• Conservation: PhyloP100: -1.31
• Publications: 0 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: Benign. The variant received -14 ACMG points.

• BP4: Computational evidence support a benign effect (BayesDel_noAF=-0.87).
• BP6: Variant 15-40604974-A-G is Benign according to our data. Variant chr15-40604974-A-G is described in ClinVar as [Likely_benign]. Clinvar id is 1218883.Status of the report is criteria_provided_single_submitter, 1 stars.
• BS1: Variant frequency is greater than expected in population afr. GnomAd4 allele frequency = 0.0127 (1932/152326) while in subpopulation AFR AF = 0.044 (1827/41558). AF 95% confidence interval is 0.0423. There are 41 homozygotes in GnomAd4. There are 909 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check.
• BS2: High Homozygotes in GnomAd4 at 41 AR gene

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KNL1	NM_144508.5	c.36-136A>G		intron_variant	Intron 2 of 25	ENST00000399668.7	NP_653091.3
KNL1	NM_170589.5	c.36-136A>G		intron_variant	Intron 2 of 26		NP_733468.3

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KNL1	ENST00000399668.7	c.36-136A>G		intron_variant	Intron 2 of 25	1	NM_144508.5	ENSP00000382576.3

Frequencies

GnomAD3 genomes AF: 0.0127 AC: 1927 AN: 152208 Hom.: 41 Cov.: 32

Gnomad AFR AF: 0.0440

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00484

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000942

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000220

Gnomad OTH AF: 0.00718

GnomAD4 exome AF: 0.00188 AC: 820 AN: 435358 Hom.: 22 AF XY: 0.00165 AC XY: 380 AN XY: 230866

African (AFR) AF: 0.0469 AC: 608 AN: 12962

American (AMR) AF: 0.00306 AC: 61 AN: 19962

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 12948

East Asian (EAS) AF: 0.00 AC: 0 AN: 33114

South Asian (SAS) AF: 0.000190 AC: 7 AN: 36776

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 42448

Middle Eastern (MID) AF: 0.00424 AC: 8 AN: 1888

European-Non Finnish (NFE) AF: 0.000124 AC: 31 AN: 250810

Other (OTH) AF: 0.00429 AC: 105 AN: 24450

GnomAD4 genome AF: 0.0127 AC: 1932 AN: 152326 Hom.: 41 Cov.: 32 AF XY: 0.0122 AC XY: 909 AN XY: 74488

African (AFR) AF: 0.0440 AC: 1827 AN: 41558

American (AMR) AF: 0.00484 AC: 74 AN: 15304

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 3470

East Asian (EAS) AF: 0.00 AC: 0 AN: 5194

South Asian (SAS) AF: 0.00 AC: 0 AN: 4832

European-Finnish (FIN) AF: 0.0000942 AC: 1 AN: 10620

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 294

European-Non Finnish (NFE) AF: 0.000220 AC: 15 AN: 68032

Other (OTH) AF: 0.00711 AC: 15 AN: 2110

Alfa AF: 0.0120 Hom.: 2

Bravo AF: 0.0151

Asia WGS AF: 0.00289 AC: 10 AN: 3476

ClinVar

Significance: Likely benign

Submissions summary: Benign:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Benign:1

Sep 22, 2018

GeneDx

Significance: Likely benign

Review Status: criteria provided, single submitter

Collection Method: clinical testing

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.87
CADD	Benign	1.8
DANN	Benign	0.65
PhyloP100		-1.3
Mutation Taster		=100/0	polymorphism

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: rs115347081; hg19: chr15-40897172;