14-66508547-T-G

Variant summary

Our verdict is Uncertain significance. Variant got 2 ACMG points: 2P and 0B. PM2

The NM_020806.5(GPHN):c.20T>G(p.Ile7Ser) variant causes a missense change. The variant allele was found at a frequency of 0.000000684 in 1,461,776 control chromosomes in the GnomAD database, with no homozygous occurrence. Variant has been reported in ClinVar as Uncertain significance (★). Another variant affecting the same amino acid position, but resulting in a different missense (i.e. I7T) has been classified as Uncertain significance.

• Frequency:
  • Genomes: not found (cov: 33)
  • Exomes 𝑓: 6.8e-7 (0 hom.)
• Consequence: GPHN NM_020806.5 missense
• Clinical Significance: Uncertain significance criteria provided, single submitter U:1
• Conservation: PhyloP100: 7.12

Genes affected

GPHN (HGNC:15465): (gephyrin) This gene encodes a neuronal assembly protein that anchors inhibitory neurotransmitter receptors to the postsynaptic cytoskeleton via high affinity binding to a receptor subunit domain and tubulin dimers. In nonneuronal tissues, the encoded protein is also required for molybdenum cofactor biosynthesis. Mutations in this gene may be associated with the neurological condition hyperplexia and also lead to molybdenum cofactor deficiency. Numerous alternatively spliced transcript variants encoding different isoforms have been described; however, the full-length nature of all transcript variants is not currently known. [provided by RefSeq, Jul 2008]

(HGNC:):

ACMG classification

Verdict is Uncertain_significance. Variant got 2 ACMG points.

• PM2: Very rare variant in population databases, with high coverage

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
GPHN	NM_020806.5	c.20T>G	p.Ile7Ser	missense_variant	1/23	ENST00000478722.6

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
GPHN	ENST00000478722.6	c.20T>G	p.Ile7Ser	missense_variant	1/23	1	NM_020806.5

Frequencies

GnomAD3 genomes Cov.: 33

GnomAD4 exome AF: 6.84e-7 AC: 1 AN: 1461776 Hom.: 0 Cov.: 30 AF XY: 0.00000138 AC XY: 1 AN XY: 727200

Gnomad4 AFR exome AF: 0.00

Gnomad4 AMR exome AF: 0.00

Gnomad4 ASJ exome AF: 0.00

Gnomad4 EAS exome AF: 0.00

Gnomad4 SAS exome AF: 0.00

Gnomad4 FIN exome AF: 0.00

Gnomad4 NFE exome AF: 8.99e-7

Gnomad4 OTH exome AF: 0.00

GnomAD4 genome Cov.: 33

ClinVar

Significance: Uncertain significance

Submissions summary: Uncertain:1

Revision: criteria provided, single submitter

Submissions by phenotype

Sulfite oxidase deficiency due to molybdenum cofactor deficiency type C Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Invitae

Dec 12, 2023

This sequence change replaces isoleucine, which is neutral and non-polar, with serine, which is neutral and polar, at codon 7 of the GPHN protein (p.Ile7Ser). This variant is not present in population databases (gnomAD no frequency). This variant has not been reported in the literature in individuals affected with GPHN-related conditions. An algorithm developed to predict the effect of missense changes on protein structure and function (PolyPhen-2) suggests that this variant is likely to be tolerated. In summary, the available evidence is currently insufficient to determine the role of this variant in disease. Therefore, it has been classified as a Variant of Uncertain Significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
AlphaMissense	Benign	0.33
BayesDel_addAF	Pathogenic	0.27	D
BayesDel_noAF	Pathogenic	0.15
Cadd	Pathogenic	26
Dann	Uncertain	0.98
DEOGEN2	Benign	0.30	T;.;.;T
Eigen	Benign	0.083
Eigen_PC	Uncertain	0.26
FATHMM_MKL	Benign	0.64	D
LIST_S2	Uncertain	0.94	D;D;D;D
M_CAP	Pathogenic	0.39	D
MetaRNN	Uncertain	0.59	D;D;D;D
MetaSVM	Benign	-0.96	T
MutationAssessor	Benign	0.55	N;N;.;.
MutationTaster	Benign	1.0	D;D;D;D;D
PrimateAI	Pathogenic	0.87	D
PROVEAN	Benign	-0.75	N;N;N;N
REVEL	Benign	0.28
Sift	Uncertain	0.0020	D;D;D;D
Sift4G	Uncertain	0.022	D;D;D;D
Polyphen		0.079	B;B;P;P
Vest4		0.75
MutPred		0.34		Gain of catalytic residue at D12 (P = 0.0067);Gain of catalytic residue at D12 (P = 0.0067);Gain of catalytic residue at D12 (P = 0.0067);Gain of catalytic residue at D12 (P = 0.0067);
MVP		0.52
MPC		1.2
ClinPred		0.94	D
GERP RS		5.2
Varity_R		0.64
gMVP		0.64

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

Publications

No publications associated with this variant yet.

Other links and lift over

hg19: chr14-66975265;