chr1-173755961-C-T

Variant names:

• chr1-173755961-C-T
• NM_014458.4:c.890C>T

Variant summary

Our verdict is Uncertain significance. The variant received 4 ACMG points: 4P and 0B. PM2 PP3_Moderate

The NM_014458.4(KLHL20):​c.890C>T​(p.Pro297Leu) variant causes a missense change involving the alteration of a conserved nucleotide. The variant allele was found at a frequency of 0.00000137 in 1,461,744 control chromosomes in the GnomAD database, with no homozygous occurrence. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Uncertain significance (★).

• Frequency:
  • Genomes: not found (cov: 32)
  • Exomes 𝑓: 0.0000014 (0 hom.)
• Consequence: KLHL20 NM_014458.4 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.67
• Publications: 0 publications found

Genes affected

KLHL20 (HGNC:25056): (kelch like family member 20) The protein encoded by this gene is a member of the kelch family of proteins, which is characterized by a 44-56 amino acid repeat motif. The kelch motif appears in many different polypeptide contexts and contains multiple potential protein-protein contact sites. Members of this family are present both throughout the cell and extracellularly, with diverse activities. [provided by RefSeq, Jul 2008]

KLHL20 Gene-Disease associations (from GenCC):

• neurodevelopmental disorder

  Inheritance: AD Classification: STRONG Submitted by: Ambry Genetics
• complex neurodevelopmental disorder

  Inheritance: AD Classification: MODERATE Submitted by: G2P

ACMG classification

Our verdict: Uncertain_significance. The variant received 4 ACMG points.

• PM2: Very rare variant in population databases, with high coverage
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.891

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	MANE	Protein	UniProt
KLHL20	NM_014458.4	c.890C>T	p.Pro297Leu	missense_variant	Exon 6 of 12	ENST00000209884.5	NP_055273.2

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	Exon rank	TSL	MANE	Protein	Appris	UniProt
KLHL20	ENST00000209884.5	c.890C>T	p.Pro297Leu	missense_variant	Exon 6 of 12	1	NM_014458.4	ENSP00000209884.4

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome AF: 0.00000137 AC: 2 AN: 1461744 Hom.: 0 Cov.: 30 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: 33472

American (AMR) AF: 0.00 AC: 0 AN: 44714

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 26132

East Asian (EAS) AF: 0.00 AC: 0 AN: 39676

South Asian (SAS) AF: 0.00 AC: 0 AN: 86230

European-Finnish (FIN) AF: 0.00 AC: 0 AN: 53412

Middle Eastern (MID) AF: 0.00 AC: 0 AN: 5766

European-Non Finnish (NFE) AF: 0.00000180 AC: 2 AN: 1111952

Other (OTH) AF: 0.00 AC: 0 AN: 60390

⚠️ The allele balance in gnomAD4 Exomes is highly skewed from 0.5 (p-value = 0.000203), which strongly suggests a high chance of mosaicism in these individuals.

GnomAD4 genome Cov.: 32

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Uncertain:1

May 22, 2023

GeneDx

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Not observed at significant frequency in large population cohorts (gnomAD); In silico analysis supports that this missense variant has a deleterious effect on protein structure/function; Has not been previously published as pathogenic or benign to our knowledge -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	0.99
BayesDel_addAF	Pathogenic	0.18	D
BayesDel_noAF	Uncertain	0.020
CADD	Pathogenic	30
DANN	Uncertain	1.0
DEOGEN2	Uncertain	0.60	D
Eigen	Pathogenic	0.89
Eigen_PC	Pathogenic	0.83
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Pathogenic	1.0	D
M_CAP	Uncertain	0.23	D
MetaRNN	Pathogenic	0.89	D
MetaSVM	Uncertain	0.18	D
MutationAssessor	Uncertain	2.5	M
PhyloP100		7.7
PrimateAI	Pathogenic	0.89	D
PROVEAN	Pathogenic	-7.7	D
REVEL	Uncertain	0.63
Sift	Uncertain	0.0010	D
Sift4G	Uncertain	0.0020	D
Polyphen		1.0	D
Vest4		0.83
MutPred		0.56		Loss of disorder (P = 0.0311);
MVP		0.99
MPC		2.0
ClinPred		1.0	D
GERP RS		5.3
Varity_R		0.66
gMVP		0.72
Mutation Taster		=30/70	disease causing

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.010		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

hg19: chr1-173725100;