4-122923143-A-C

Position:

• chr4-122923143-A-C

Variant summary

Our verdict is Pathogenic. Variant got 13 ACMG points: 13P and 0B. PVS1 PS1_Moderate PM2 PP5

The NM_145207.3(SPATA5):​c.1A>C​(p.Met1?) variant causes a start lost change involving the alteration of a non-conserved nucleotide. The variant allele was found at a frequency of 0.000108 in 1,614,182 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 Conflicting classifications of pathogenicity (no stars).

• Frequency:
  • Genomes: 𝑓 0.00011 (0 hom., cov: 32)
  • Exomes 𝑓: 0.00011 (0 hom.)
• Consequence: SPATA5 NM_145207.3 start_lost
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:8 U:2
• Conservation: PhyloP100: 3.39

Genes affected

SPATA5 (HGNC:):

AFG2A (HGNC:18119): (AFG2 AAA ATPase homolog A) This gene encodes a member of the ATPase associated with diverse activities family, whose members are defined by a highly conserved ATPase domain. Members of this family participate in diverse cellular processes that include membrane fusion, DNA replication, microtubule severing, and protein degradation. The protein encoded by this gene has a putative mitochondrial targeting sequence and has been proposed to function in maintenance of mitochondrial function and integrity during mouse spermatogenesis. Allelic variants in this gene have been associated with epilepsy, hearing loss, and cognitive disability syndrome. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Sep 2016]

ACMG classification

Verdict is Pathogenic. Variant got 13 ACMG points.

• PVS1: Start lost variant, no new inframe start found.
• PS1: Another start lost variant in NM_145207.3 (SPATA5) was described as [Conflicting_classifications_of_pathogenicity] in ClinVar as 475728
• PM2: Very rare variant in population databases, with high coverage
• PP5: Variant 4-122923143-A-C is Pathogenic according to our data. Variant chr4-122923143-A-C is described in ClinVar as [Conflicting_classifications_of_pathogenicity]. Clinvar id is 203533.We mark this variant Likely_pathogenic, oryginal submissions are: {Likely_pathogenic=2, Pathogenic=2, Uncertain_significance=2}. Variant chr4-122923143-A-C is described in Lovd as [Likely_pathogenic]. Variant chr4-122923143-A-C is described in Lovd as [Likely_pathogenic].

Transcripts

RefSeq

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	MANE	UniProt
SPATA5	NM_145207.3	c.1A>C	p.Met1?	start_lost	1/16	ENST00000274008.5

Ensembl

Gene	Transcript	HGVSc	HGVSp	Effect	#exon/exons	TSL	MANE	Appris	UniProt
AFG2A	ENST00000274008.5	c.1A>C	p.Met1?	start_lost	1/16	1	NM_145207.3	P1
AFG2A	ENST00000422835.2	n.43A>C		non_coding_transcript_exon_variant	1/15	1
AFG2A	ENST00000675612.1	c.1A>C	p.Met1?	start_lost	1/17
AFG2A	ENST00000674886.1	n.66A>C		non_coding_transcript_exon_variant	1/11

Frequencies

GnomAD3 genomes AF: 0.000105 AC: 16 AN: 152186 Hom.: 0 Cov.: 32

Gnomad AFR AF: 0.0000482

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00

Gnomad ASJ AF: 0.00

Gnomad EAS AF: 0.000193

Gnomad SAS AF: 0.00

Gnomad FIN AF: 0.0000942

Gnomad MID AF: 0.00

Gnomad NFE AF: 0.000176

Gnomad OTH AF: 0.00

GnomAD3 exomes AF: 0.0000875 AC: 22 AN: 251382 Hom.: 0 AF XY: 0.000103 AC XY: 14 AN XY: 135858

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 SAS exome AF: 0.00

Gnomad FIN exome AF: 0.00

Gnomad NFE exome AF: 0.000185

Gnomad OTH exome AF: 0.000163

GnomAD4 exome AF: 0.000109 AC: 159 AN: 1461878 Hom.: 0 Cov.: 31 AF XY: 0.000117 AC XY: 85 AN XY: 727240

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: 0.000140

Gnomad4 OTH exome AF: 0.0000497

GnomAD4 genome AF: 0.000105 AC: 16 AN: 152304 Hom.: 0 Cov.: 32 AF XY: 0.0000940 AC XY: 7 AN XY: 74472

Gnomad4 AFR AF: 0.0000481

Gnomad4 AMR AF: 0.00

Gnomad4 ASJ AF: 0.00

Gnomad4 EAS AF: 0.000193

Gnomad4 SAS AF: 0.00

Gnomad4 FIN AF: 0.0000942

Gnomad4 NFE AF: 0.000176

Gnomad4 OTH AF: 0.00

Alfa AF: 0.0000761 Hom.: 0

Bravo AF: 0.0000756

TwinsUK AF: 0.00 AC: 0

ALSPAC AF: 0.000259 AC: 1

ExAC AF: 0.0000494 AC: 6

EpiCase AF: 0.000327

EpiControl AF: 0.000119

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:8 Uncertain:2

Revision: criteria provided, conflicting classifications

Submissions by phenotype

not provided Pathogenic:6

Likely pathogenic, criteria provided, single submitter	clinical testing	CeGaT Center for Human Genetics Tuebingen	May 01, 2023	AFG2A: PM2, PM3, PVS1:Moderate -
Likely pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics DNA and cytogenetics Diagnostics Lab, Erasmus MC, Erasmus Medical Center	-	- -
Pathogenic, criteria provided, single submitter	clinical testing	GeneDx	Nov 19, 2021	Reported with a de novo missense variant on the opposite allele (in trans) in a male with features of a SPATA5-related disorder who underwent trio-based whole exome sequencing (Papuc et al., 2019); Initiation codon variant in a gene for which loss-of-function is a known mechanism of disease; This variant is associated with the following publications: (PMID: 30552426) -
Likely pathogenic, no assertion criteria provided	clinical testing	Genome Diagnostics Laboratory, University Medical Center Utrecht	-	- -
Likely pathogenic, no assertion criteria provided	clinical testing	Joint Genome Diagnostic Labs from Nijmegen and Maastricht, Radboudumc and MUMC+	-	- -
Likely pathogenic, criteria provided, single submitter	clinical testing	Athena Diagnostics	Dec 08, 2017	- -

Microcephaly-intellectual disability-sensorineural hearing loss-epilepsy-abnormal muscle tone syndrome Pathogenic:2 Uncertain:1

Likely pathogenic, no assertion criteria provided	clinical testing	Clinical Genetics Laboratory, University Hospital Schleswig-Holstein	May 06, 2021	- -
Pathogenic, criteria provided, single submitter	clinical testing	Victorian Clinical Genetics Services, Murdoch Childrens Research Institute	Jul 17, 2023	Based on the classification scheme VCGS_Germline_v1.3.4, this variant is classified as Pathogenic. Following criteria are met: 0102 - Loss of function is a known mechanism of disease in this gene and is associated with neurodevelopmental disorder with hearing loss, seizures, and brain abnormalities (MIM#616577). (I) 0106 - This gene is associated with autosomal recessive disease. (I) 0206 - Variant is predicted to result in a loss of the canonical translation initiation codon (ATG). (SP) 0251 - This variant is heterozygous. (I) 0304 - Variant is present in gnomAD <0.01 for a recessive condition (v2: 27 heterozygotes, 0 homozygotes). (SP) 0311 - Multiple alternative nucleotide changes at the initiation codon are present in gnomAD (highest allele count in v2: 5 heterozygotes, 0 homozygotes). (I) 0710 - Other variants comparable to the one identified in this case have inconclusive previous evidence for pathogenicity. c.1A>T and c.1A>G are predicted to result in a loss of the canonical translation initiation codon, and have been reported as VUS by a clinical testing laboratory in individuals without a second variant that is pathogenic, likely pathogenic or VUS in SPATA5 (ClinVar, personal communication). (I) 0801 - This variant has strong previous evidence of pathogenicity in unrelated individuals. It has been reported as compound heterozygous in two affected individuals, one with encephalopathy and seizures, the other with clinical features including global developmental delay and hearing impairment (PMID: 30552426, DDD study). This variant has also been reported by multiple clinical testing laboratories as likely pathogenic or pathogenic (ClinVar). In addition, it has been reported as a VUS by a clinical testing laboratory in individuals without a second variant that is pathogenic, likely pathogenic or VUS in SPATA5 (ClinVar, personal communication). (SP) 1206 - This variant has been shown to be paternally inherited (by trio analysis). (I) Legend: (SP) - Supporting pathogenic, (I) - Information, (SB) - Supporting benign -
Uncertain significance, criteria provided, single submitter	clinical testing	Labcorp Genetics (formerly Invitae), Labcorp	Aug 09, 2022	This sequence change affects the initiator methionine of the SPATA5 mRNA. The next in-frame methionine is located at codon 75. This variant is present in population databases (rs552219028, gnomAD 0.02%). Disruption of the initiator codon has been observed in individual(s) with early-onset epileptic encephalopathy (PMID: 30552426). ClinVar contains an entry for this variant (Variation ID: 203533). 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. -

not specified Uncertain:1

Uncertain significance, criteria provided, single submitter

clinical testing

Women's Health and Genetics/Laboratory Corporation of America, LabCorp

Mar 12, 2024

Variant summary: SPATA5 c.1A>C (p.Met1Leu) alters the initiation codon and is predicted to result either in absence of the protein or truncation of the encoded protein due to translation initiation at a downstream codon. The next downstream in-frame Met is found at codon 75. No non-NMD-causing variants upstream of this codon have been classified as pathogenic. Three of four in-silico tools predict a damaging effect of the variant on protein function. The variant allele was found at a frequency of 8.8e-05 in 251382 control chromosomes (gnomAD). c.1A>C has been reported in the literature in an individual affected with early-onset epileptic encephalopathy (Papuc_2019). These data do not allow any conclusion about variant significance. To our knowledge, no experimental evidence demonstrating an impact on protein function has been reported. The following publication has been ascertained in the context of this evaluation (PMID: 30552426). ClinVar contains an entry for this variant (Variation ID: 203533). Based on the evidence outlined above, the variant was classified as uncertain significance. -

Computational scores

Source: dbNSFP v4.3

Name	Calibrated prediction	Score	Prediction
BayesDel_addAF	Pathogenic	0.39	D
BayesDel_noAF	Pathogenic	0.60
CADD	Benign	22
DANN	Benign	0.93
DEOGEN2	Benign	0.010	T
Eigen	Uncertain	0.21
Eigen_PC	Benign	0.20
FATHMM_MKL	Benign	0.51	D
LIST_S2	Uncertain	0.90	D
M_CAP	Pathogenic	0.96	D
MetaRNN	Pathogenic	0.98	D
MetaSVM	Pathogenic	0.82	D
MutationTaster	Benign	1.0	D
PROVEAN	Benign	-0.58	N
REVEL	Pathogenic	0.71
Sift	Pathogenic	0.0	D
Sift4G	Pathogenic	0.0	D
Polyphen		0.52	P
Vest4		0.76
MutPred		0.99		Gain of glycosylation at S2 (P = 8e-04);
MVP		0.93
ClinPred		0.98	D
GERP RS		4.0
RBP_binding_hub_radar		0.0
RBP_regulation_power_radar		1.7
Varity_R		0.97
gMVP		0.24

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: rs552219028; hg19: chr4-123844298;