chr14-31850092-T-C

Variant names:

• chr14-31850092-T-C
• rs118161496
• NM_025152.3:c.815-27T>C

Variant summary

Our verdict is Likely benign. The variant received -3 ACMG points: 2P and 5B. PP3 PP5 BS1_Supporting BS2

The NM_025152.3(NUBPL):​c.815-27T>C variant causes a intron change. The variant allele was found at a frequency of 0.00373 in 1,571,878 control chromosomes in the GnomAD database, including 22 homozygotes. In-silico tool predicts a benign outcome for this variant. Variant has been reported in ClinVar as Conflicting classifications of pathogenicity (no stars). There are indicators that this mutation may affect the branch point..

• Frequency:
  • Genomes: 𝑓 0.0034 (3 hom., cov: 32)
  • Exomes 𝑓: 0.0038 (19 hom.)
• Consequence: NUBPL NM_025152.3 intron
• Clinical Significance: Conflicting classifications of pathogenicity criteria provided, conflicting classifications P:11 U:6
• Conservation: PhyloP100: 3.77
• Publications: 14 publications found

Genes affected

NUBPL (HGNC:20278): (NUBP iron-sulfur cluster assembly factor, mitochondrial) This gene encodes a member of the Mrp/NBP35 ATP-binding proteins family. The encoded protein is required for the assembly of the respiratory chain NADH dehydrogenase (complex I), an oligomeric enzymatic complex located in the inner mitochondrial membrane. Mutations in this gene cause mitochondrial complex I deficiency. Alternative splicing results in multiple transcript variants. [provided by RefSeq, May 2014]

NUBPL Gene-Disease associations (from GenCC):

• mitochondrial complex I deficiency, nuclear type 21

  Inheritance: AR Classification: DEFINITIVE, STRONG Submitted by: G2P, Labcorp Genetics (formerly Invitae)
• Leigh syndrome

  Inheritance: AR Classification: MODERATE Submitted by: ClinGen
• mitochondrial complex I deficiency

  Inheritance: AR Classification: SUPPORTIVE Submitted by: Orphanet

ACMG classification

Our verdict: Likely_benign. The variant received -3 ACMG points.

• PP3: Splicing predictors support a deleterious effect. Scorers claiming Pathogenic: max_spliceai. No scorers claiming Uncertain. No scorers claiming Benign.
• PP5: Variant 14-31850092-T-C is Pathogenic according to our data. Variant chr14-31850092-T-C is described in ClinVar as Conflicting_classifications_of_pathogenicity. ClinVar VariationId is 50317.
• BS1: Variant frequency is greater than expected in population nfe. GnomAd4 allele frequency = 0.00339 (516/152374) while in subpopulation NFE AF = 0.00442 (301/68042). AF 95% confidence interval is 0.00401. There are 3 homozygotes in GnomAd4. There are 271 alleles in the male GnomAd4 subpopulation. Median coverage is 32. This position passed quality control check. Existence of Clinvar submissions makes me limit the strength of this signal to Supporting
• BS2: High Homozygotes in GnomAd4 at 3 AR gene

Variant Effect in Transcripts

ACMG analysis was done for transcript: NM_025152.3. You can select a different transcript below to see updated ACMG assignments.

RefSeq Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NUBPL	NM_025152.3	MANE Select	c.815-27T>C		intron	N/A	NP_079428.2
	NUBPL	NM_001201573.2		c.527-27T>C		intron	N/A	NP_001188502.1
	NUBPL	NM_001201574.2		c.266-27T>C		intron	N/A	NP_001188503.1

Ensembl Transcripts

Selected	Gene	Transcript	Tags	HGVSc	HGVSp	Effect	Exon Rank	Protein	UniProt
	NUBPL	ENST00000281081.12	TSL:1 MANE Select	c.815-27T>C		intron	N/A	ENSP00000281081.7
	NUBPL	ENST00000551015.1	TSL:4	n.574T>C		non_coding_transcript_exon	Exon 4 of 4
	NUBPL	ENST00000550649.5	TSL:5	c.413-27T>C		intron	N/A	ENSP00000447618.1

Frequencies

GnomAD3 genomes AF: 0.00340 AC: 517 AN: 152256 Hom.: 3 Cov.: 32

Gnomad AFR AF: 0.000579

Gnomad AMI AF: 0.00

Gnomad AMR AF: 0.00131

Gnomad ASJ AF: 0.000288

Gnomad EAS AF: 0.00

Gnomad SAS AF: 0.00145

Gnomad FIN AF: 0.0149

Gnomad MID AF: 0.00316

Gnomad NFE AF: 0.00444

Gnomad OTH AF: 0.00191

GnomAD2 exomes AF: 0.00345 AC: 857 AN: 248676 AF XY: 0.00349

Gnomad AFR exome AF: 0.000777

Gnomad AMR exome AF: 0.000726

Gnomad ASJ exome AF: 0.00

Gnomad EAS exome AF: 0.00

Gnomad FIN exome AF: 0.0122

Gnomad NFE exome AF: 0.00442

Gnomad OTH exome AF: 0.00513

GnomAD4 exome AF: 0.00377 AC: 5351 AN: 1419504 Hom.: 19 Cov.: 25 AF XY: 0.00373 AC XY: 2645 AN XY: 709074

African (AFR) AF: 0.000459 AC: 15 AN: 32676

American (AMR) AF: 0.000806 AC: 36 AN: 44642

Ashkenazi Jewish (ASJ) AF: 0.00 AC: 0 AN: 25846

East Asian (EAS) AF: 0.00 AC: 0 AN: 39434

South Asian (SAS) AF: 0.00108 AC: 92 AN: 85298

European-Finnish (FIN) AF: 0.0124 AC: 661 AN: 53348

Middle Eastern (MID) AF: 0.00140 AC: 8 AN: 5698

European-Non Finnish (NFE) AF: 0.00407 AC: 4370 AN: 1073574

Other (OTH) AF: 0.00286 AC: 169 AN: 58988

GnomAD4 genome AF: 0.00339 AC: 516 AN: 152374 Hom.: 3 Cov.: 32 AF XY: 0.00364 AC XY: 271 AN XY: 74508

African (AFR) AF: 0.000577 AC: 24 AN: 41588

American (AMR) AF: 0.00131 AC: 20 AN: 15306

Ashkenazi Jewish (ASJ) AF: 0.000288 AC: 1 AN: 3468

East Asian (EAS) AF: 0.00 AC: 0 AN: 5190

South Asian (SAS) AF: 0.00145 AC: 7 AN: 4834

European-Finnish (FIN) AF: 0.0149 AC: 158 AN: 10626

Middle Eastern (MID) AF: 0.00340 AC: 1 AN: 294

European-Non Finnish (NFE) AF: 0.00442 AC: 301 AN: 68042

Other (OTH) AF: 0.00189 AC: 4 AN: 2116

Alfa AF: 0.00166 Hom.: 4

Bravo AF: 0.00228

Asia WGS AF: 0.000289 AC: 1 AN: 3476

ClinVar

Significance: Conflicting classifications of pathogenicity

Submissions summary: Pathogenic:11 Uncertain:6

Revision: criteria provided, conflicting classifications

Submissions by phenotype

Mitochondrial complex I deficiency, nuclear type 21 Pathogenic:7 Uncertain:2

Apr 08, 2025

Undiagnosed Diseases Network, NIH

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

This variant has been previously reported, often co-occurring in cis with the c.166G>A (p.G56R) variant, in a homozygous state or in conjunction with another variant in individuals with mitochondrial complex I deficiency (PMID: 20818383, 23553477, 29417091, 32518176). Fibroblasts from patients with this variant produces diminished residual complex I activity (PMID: 20818383). This intronic variant is predicted to alter splicing (SpliceAI: 0.710, Acceptor Loss), impact the native branch site, and may lead toexon 10 skipping (PMID 20818383).

May 04, 2022

Mendelics

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Oct 19, 2020

Victorian Clinical Genetics Services, Murdoch Childrens Research Institute

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Based on the classification scheme VCGS_Germline_v1.1.1, this variant is classified as 3B-VUS. Following criteria are met: 0102 - Loss-of-function is a known mechanism of disease for this gene. (N) 0106 - This gene is known to be associated with autosomal recessive disease. (N) 0210 - Splice site variant (canonical or non-canonical) proven to affect splicing/expression of the transcript with a known effect on protein structure. Functional studies showed three alternate transcripts were generated as a result of aberrant splicing from the allele with this variant: one transcript with normal splicing, one with exon 10 skipped resulting in a frameshift but no nonsense-mediated decay (NMD), and a third transcript that utilised a cryptic splice site resulting in a frameshift and NMD (PMIDs: 22072591, 32518176). (P) 0251 - Variant is heterozygous. (N) 0305 - Variant is present in gnomAD >=0.01 and <0.03 for a recessive condition (972 heterozygotes, 10 homozygotes). (N) 0705 - No comparable variants have previous evidence for pathogenicity. (N) 0803 - Low previous evidence of pathogenicity in unrelated individuals. An allele harbouring this variant in cis with a second variant (p.(Gly56Arg)) has been reported as pathogenic in many patients, majority of whom were in compound heterozygous state with a pathogenic allele (PMIDs: 22072591, 25245479, 23553477). However, an allele harbouring this variant without the p.(Gly56Arg) variant has been associated with disease in one family (PMID: 32518176). (P) 1001 - Strong functional evidence supporting abnormal protein function. Functional studies showed levels of NUBPL mRNA and protein were decreased in the fibroblast cells heterozygous for this variant alone (PMID: 22072591). (P) 1205 - Variant is maternally inherited. (N) Legend: (P) - Pathogenic, (N) - Neutral, (B) - Benign

Jul 20, 2021

OMIM

Significance: Pathogenic

Review Status: no assertion criteria provided

Collection Method: literature only

Aug 22, 2024

Clinical Genetics Laboratory, University Hospital Schleswig-Holstein

Significance: Likely pathogenic

Review Status: no assertion criteria provided

Collection Method: clinical testing

Nov 21, 2022

Department of Pathology and Laboratory Medicine, Sinai Health System

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: research

Jan 08, 2024

Revvity Omics, Revvity

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Jun 15, 2018

Institute for Genomic Medicine (IGM) Clinical Laboratory, Nationwide Children's Hospital

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

[ACMG/AMP: PS3, PP3, PP5, BS1] This alteration is supported by well-established in vitro or in vivo functional studies to have a damaging effect on protein function or splicing [PS3], is predicted to be damaging by multiple functional prediction tools [PP3], was reported as a pathogenic/likely pathogenic alteration by a reputable source (ClinVar or other correspondence from a clinical testing laboratory) [PP5], has an allele frequency that is greater than expected for the associated disease [BS1].

Aug 24, 2020

Undiagnosed Diseases Network, NIH

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

not provided Pathogenic:3 Uncertain:2

Mar 01, 2025

CeGaT Center for Human Genetics Tuebingen

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

NUBPL: PM3:Strong, PS3:Moderate, PM2:Supporting, PP3, BS2

Aug 14, 2017

GeneDx

Significance: Pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Expression studies of the c.815-27 T>C sequence change found that this variant impairs mRNA splicing resulting in a 80% decrease in complex I assembly and function (Tucker et al., 2012; Wydro et al., 2013). Therefore, based on the currently available information, the c.815-27 T>C variant is a strong candidate for a pathogenic variant; however, the possibility that it is a benign variant cannot be excluded.

Jan 09, 2017

Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Jul 09, 2024

Mayo Clinic Laboratories, Mayo Clinic

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

PP1, PP3, PM3, PS3

Jul 15, 2025

Laboratory of Genetics, Children's Clinical University Hospital Latvia

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Inborn genetic diseases Pathogenic:1

Apr 13, 2021

Ambry Genetics

Significance: Likely pathogenic

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.815-27T>C intronic alteration consists of a T to C substitution 27 nucleotides before coding exon 10 in the NUBPL gene and is predicted to affect the native branch site. Based on data from the Genome Aggregation Database (gnomAD) database, the NUBPL c.815-27T>C alteration was observed in 0.35% (992/280082) of total alleles studied (including 10 homozygotes), with a frequency of 1.24% (310/24978) in the European (Finnish) subpopulation. The [c.166G>A (p.G56R); c.815-27T>C] complex allele has been reported in the homozygous state, compound heterozygous state, and confirmed in trans with a second pathogenic allele in multiple unrelated patients with mitochondrial encephalomyopathy (Calvo, 2010; Kevelam, 2013). Emerging evidence is suggestive that the NUBPL [c.166G>A (p.G56R); c.815-27T>C] complex allele is likely pathogenic when these alterations are in cis; however, the clinical significance of these alterations in isolation remains uncertain. The c.815-27T nucleotide is highly conserved in available vertebrate species. Functional analysis of cultured fibroblasts from a patient bearing the [c.166G>A (p.G56R); c.815-27T>C] complex allele in trans with a complex rearrangement, as well as a control patient who was heterozygous for only the c.815-27T>C alteration, demonstrated an aberrant RT-PCR pattern with three distinct transcripts: wild-type, a lengthened transcript resulting from a cryptic splice site which introduces an additional 72 bp and results in a frameshift (p.G272Vfs*11), as well as a truncated transcript generated due to exon 10 skipping resulting in a frameshift (p.D273Qfs*31) (Tucker, 2012). Analysis by qRT-PCR and Western blot showed that the heterozygous control with only the c.815-27T>C alteration had reduced mRNA expression (74%) and protein expression (59%) compared to wild type controls, and the patient with the [c.166G>A (p.G56R); c.815-27T>C] complex allele and complex rearrangement on the other allele had more significant reduction in mRNA expression (15%) and undetectable protein expression (Tucker, 2012). No defective function was identified when the protein with the G56R missense change was over-expressed (Tucker, 2012). The p.D273Qfs*31 transcript is completely non-functional in yeast assays (Wydro, 2013; Maclean, 2018). In silico splice site analysis predicts that the c.815-27T>C alteration will weaken the native splice acceptor site and will result in the creation or strengthening of a novel splice acceptor site. Based on the available evidence, this alteration is classified as likely pathogenic.

not specified Uncertain:1

Nov 12, 2024

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

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

Variant summary: NUBPL c.815-27T>C is located at a position not widely known to affect splicing. Consensus agreement among computation tools predict no significant impact on normal splicing. At least one publication reports experimental evidence that this variant affects mRNA splicing (Tucker_2012, Kimonis_2021, Calvo_2010). The variant allele was found at a frequency of 0.0037 in 1571878 control chromosomes in the gnomAD database (v4), including 22 homozygotes. The observed variant frequency exceeds the estimated maximal expected allele frequency for a pathogenic variant in NUBPL causing Mitochondrial Complex 1 Deficiency, Nuclear Type 21 phenotype. c.815-27T>C has been reported in the literature in multiple individuals affected with Mitochondrial Complex 1 Deficiency, Nuclear Type 21 (Calvo_2010, Kevelam_2013, Haskell_2018, Maclean_2018, Kimonis_2021), however it is usually observed in cis with the c.166G>A (p.G56R) variant. These data indicate that the variant may be associated with disease. At least one publication reports experimental evidence evaluating an impact on protein expression, finding that a heterozygous control with the variant exhibited far lower expression of NUBPL protein (Tucker_2012). The following publications have been ascertained in the context of this evaluation (PMID: 20818383, 23553477, 22072591, 32518176, 29982452, 29417091). ClinVar contains an entry for this variant (Variation ID: 50317). There is not enough evidence at this time to determine if this variant is associated with disease in isolation. Based on the evidence outlined above, the variant was classified as VUS-possibly pathogenic.

Mitochondrial complex I deficiency Uncertain:1

Feb 16, 2024

Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine

Significance: Uncertain significance

Review Status: criteria provided, single submitter

Collection Method: clinical testing

The c.815-27T>C variant in NUBPL is typically observed as a compound allele (in cis) with the c.166G>A [p.G56R] variant in individuals with mitochondrial complex I deficiency. By itself, it has been reported in at least one individual with mitochondrial complex I deficiency and an another variant in trans, and segregated with disease in at least 1 sibling (Kimonis 2021 PMID: 32518176; Maclean 2018 PMID:29982452). This variant has also been identified in 1.28% (819/63974) of European (Finnish) chromosomes, including 22 homozygotes, by gnomAD (http://gnomad.broadinstitute.org, v4.0.0) and reported in ClinVar (Variation ID 50317). This variant is located in the splice branch site, and computational prediction tools suggest an impact on splicing. An RT-PCR study demonstrated that this variant results in three transcripts: wild-type, the use of a cryptic acceptor site (p.G272VfsX11), or skipping of exon 10 (p.D273QfsX31). In addition, in vitro functional studies demonstrated that patient cells express reduced levels of the wild-type transcript, possibly as a result of degradation of a variant transcript by NMD (Tucker 2012 PMID: 22072591). Overall, it is unclear if this variant in isolation causes disease or whether it acts in synergy with the p.G56R variant. Therefore, while there is some suspicion for a pathogenic role, the clinical significance of this variant is uncertain. ACMG/AMP Criteria applied: PM3, PP1, PP3, PS3_Supporting, BS1_Supporting.

Computational scores

Source: dbNSFP v4.9

Name	Calibrated prediction	Score	Prediction
BayesDel_noAF	Benign	-0.79
CADD	Benign	22
DANN	Benign	0.68
PhyloP100		3.8
BranchPoint Hunter		6.0
Mutation Taster		=100/0	disease causing (ClinVar)

Splicing

Name	Calibrated prediction	Score	Prediction
SpliceAI score (max)		0.71		Details are displayed if max score is > 0.2
DS_AG_spliceai		0.70		Position offset: -45
DS_AL_spliceai		0.71		Position offset: 27

Find out detailed SpliceAI scores and Pangolin per-transcript scores at spliceailookup.broadinstitute.org

Other links and lift over

dbSNP: rs118161496; hg19: chr14-32319298;