chr17-41612316-T-C

Position:

• chr17-41612316-T-C

Variant summary

Our verdict is Pathogenic. Variant got 12 ACMG points: 12P and 0B. PM1 PM2 PM5 PP3_Strong PP5_Moderate

The NM_005557.4(KRT16):​c.373A>G​(p.Asn125Asp) variant causes a missense change. The variant was absent in control chromosomes in GnomAD project. In-silico tool predicts a pathogenic outcome for this variant. Variant has been reported in ClinVar as Pathogenic (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. N125G) has been classified as Pathogenic.

• Frequency: Genomes: not found (cov: 32)
• Consequence: KRT16 NM_005557.4 missense
• Clinical Significance: Pathogenic criteria provided, single submitter P:2 O:1
• Conservation: PhyloP100: 5.06

Genes affected

KRT16 (HGNC:6423): (keratin 16) The protein encoded by this gene is a member of the keratin gene family. The keratins are intermediate filament proteins responsible for the structural integrity of epithelial cells and are subdivided into cytokeratins and hair keratins. Most of the type I cytokeratins consist of acidic proteins which are arranged in pairs of heterotypic keratin chains and are clustered in a region of chromosome 17q12-q21. This keratin has been coexpressed with keratin 14 in a number of epithelial tissues, including esophagus, tongue, and hair follicles. Mutations in this gene are associated with type 1 pachyonychia congenita, non-epidermolytic palmoplantar keratoderma and unilateral palmoplantar verrucous nevus. [provided by RefSeq, Jul 2008]

ACMG classification

Verdict is Pathogenic. Variant got 12 ACMG points.

• PM1: In a hotspot region, there are 6 aminoacids with missense pathogenic changes in the window of +-8 aminoacids around while only 0 benign, 3 uncertain in NM_005557.4
• PM2: Very rare variant in population databases, with high coverage
• PM5: Other missense variant is known to change same aminoacid residue: Variant chr17-41612315-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 14602.Status of the report is criteria_provided_multiple_submitters_no_conflicts, 2 stars.
• PP3: MetaRNN computational evidence supports a deleterious effect, 0.99
• PP5: Variant 17-41612316-T-C is Pathogenic according to our data. Variant chr17-41612316-T-C is described in ClinVar as [Pathogenic]. Clinvar id is 66608.Status of the report is criteria_provided_single_submitter, 1 stars. Variant chr17-41612316-T-C is described in Lovd as [Pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
KRT16	NM_005557.4	c.373A>G	p.Asn125Asp	missense_variant	1/8	ENST00000301653.9

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
KRT16	ENST00000301653.9	c.373A>G	p.Asn125Asp	missense_variant	1/8	1	NM_005557.4	P1
KRT16	ENST00000593067.1	c.-312-30A>G		intron_variant		3
KRT16	ENST00000588319.1	n.450A>G		non_coding_transcript_exon_variant	1/1

Frequencies

GnomAD3 genomes Cov.: 32

GnomAD4 exome Cov.: 31

GnomAD4 genome Cov.: 32

ClinVar

Significance: Pathogenic

Submissions summary: Pathogenic:2 Other:1

Revision: criteria provided, single submitter

Submissions by phenotype

not provided Pathogenic:1 Other:1

not provided, no classification provided	literature only	Epithelial Biology; Institute of Medical Biology, Singapore	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Jan 04, 2016	The N125D pathogenic variant has been reported previously in association with pachyonychia congenita (Smith et al., 2005; Fu et al., 2011; Wilson et al., 2014). It was not observed in approximately 6,500 individuals of European and African American ancestry in the NHLBI Exome Sequencing Project, indicating it is not a common benign variant in these populations. N125D is a semi-conservative amino acid substitution, which may impact secondary protein structure as these residues differ in some properties. This substitution occurs within a known hotspot region (helix initiation motif) that is highly conserved across all species and among all members of the keratin family. Many other pathogenic variants in patients with pachyonychia congenita have been reported at the same codon (N125S) and in nearby residues (L124H/R/P, R127C/S/G) according to the Human Gene Mutation Database (Stenson et al., 2014). It is well established that keratin gene variants affecting the residues at the ends of the central rod domains of the keratin proteins (helix initiation and termination motifs) interfere with proper keratin intermediate filament assembly and function, resulting in hyperkeratosis (Chamcheu et al., 2011). Therefore, we consider N125D to be pathogenic. -

Pachyonychia congenita 1 Pathogenic:1

Pathogenic, no assertion criteria provided

literature only

OMIM

Oct 01, 2005

- -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Pathogenic	1.0
BayesDel_addAF	Pathogenic	0.24	D
BayesDel_noAF	Uncertain	0.11
CADD	Pathogenic	26
DANN	Uncertain	1.0
DEOGEN2	Pathogenic	0.86	D
Eigen	Pathogenic	0.70
Eigen_PC	Uncertain	0.55
FATHMM_MKL	Pathogenic	0.98	D
LIST_S2	Uncertain	0.96	D
M_CAP	Uncertain	0.27	D
MetaRNN	Pathogenic	0.99	D
MetaSVM	Pathogenic	1.1	D
MutationAssessor	Pathogenic	4.9	H
MutationTaster	Benign	1.0	D
PrimateAI	Uncertain	0.57	T
PROVEAN	Pathogenic	-4.5	D
REVEL	Pathogenic	0.85
Sift	Uncertain	0.0010	D
Sift4G	Pathogenic	0.0	D
Polyphen		1.0	D
Vest4		0.78
MutPred		0.98		Gain of phosphorylation at S130 (P = 0.1166);
MVP		0.89
MPC		1.1
ClinPred		1.0	D
GERP RS		3.3
Varity_R		0.93
gMVP		1.0

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

LitVar

Other links and lift over

dbSNP: rs58608173; hg19: chr17-39768568;