Submissions for variant NC_012920.1:m.1555A>G

dbSNP: rs267606617

Total submissions: 18

Submitter	RCV	SCV	Clinical significance	Condition	Last evaluated	Review status	Method	Comment
PharmGKB	RCV001787321	SCV000268276	drug response	aminoglycoside antibacterials response - Toxicity	2021-06-15	reviewed by expert panel	curation	PharmGKB Level of Evidence 1A: Level 1A clinical annotations describe variant-drug combinations that have variant-specific prescribing guidance available in a current clinical guideline annotation or an FDA-approved drug label annotation. Annotations of drug labels or clinical guidelines must give prescribing guidance for specific variants (e.g. CYP2C9*3, HLA-B*57:01) or provide mapping from defined allele functions to diplotypes and phenotypes to be used as supporting evidence for a level 1A clinical annotation. Level 1A clinical annotations must also be supported by at least one publication in addition to a clinical guideline or drug label with variant-specific prescribing guidance.
PharmGKB	RCV001787374	SCV002031224	drug response	gentamicin response - Toxicity	2021-06-15	reviewed by expert panel	curation	PharmGKB Level of Evidence 1A: Level 1A clinical annotations describe variant-drug combinations that have variant-specific prescribing guidance available in a current clinical guideline annotation or an FDA-approved drug label annotation. Annotations of drug labels or clinical guidelines must give prescribing guidance for specific variants (e.g. CYP2C9*3, HLA-B*57:01) or provide mapping from defined allele functions to diplotypes and phenotypes to be used as supporting evidence for a level 1A clinical annotation. Level 1A clinical annotations must also be supported by at least one publication in addition to a clinical guideline or drug label with variant-specific prescribing guidance.
PharmGKB	RCV001787375	SCV002031225	drug response	amikacin response - Toxicity	2021-06-15	reviewed by expert panel	curation	PharmGKB Level of Evidence 1A: Level 1A clinical annotations describe variant-drug combinations that have variant-specific prescribing guidance available in a current clinical guideline annotation or an FDA-approved drug label annotation. Annotations of drug labels or clinical guidelines must give prescribing guidance for specific variants (e.g. CYP2C9*3, HLA-B*57:01) or provide mapping from defined allele functions to diplotypes and phenotypes to be used as supporting evidence for a level 1A clinical annotation. Level 1A clinical annotations must also be supported by at least one publication in addition to a clinical guideline or drug label with variant-specific prescribing guidance.
PharmGKB	RCV001787376	SCV002031226	drug response	kanamycin response - Toxicity	2021-06-15	reviewed by expert panel	curation	PharmGKB Level of Evidence 1A: Level 1A clinical annotations describe variant-drug combinations that have variant-specific prescribing guidance available in a current clinical guideline annotation or an FDA-approved drug label annotation. Annotations of drug labels or clinical guidelines must give prescribing guidance for specific variants (e.g. CYP2C9*3, HLA-B*57:01) or provide mapping from defined allele functions to diplotypes and phenotypes to be used as supporting evidence for a level 1A clinical annotation. Level 1A clinical annotations must also be supported by at least one publication in addition to a clinical guideline or drug label with variant-specific prescribing guidance.
PharmGKB	RCV001787377	SCV002031227	drug response	streptomycin response - Toxicity	2021-06-15	reviewed by expert panel	curation	PharmGKB Level of Evidence 1A: Level 1A clinical annotations describe variant-drug combinations that have variant-specific prescribing guidance available in a current clinical guideline annotation or an FDA-approved drug label annotation. Annotations of drug labels or clinical guidelines must give prescribing guidance for specific variants (e.g. CYP2C9*3, HLA-B*57:01) or provide mapping from defined allele functions to diplotypes and phenotypes to be used as supporting evidence for a level 1A clinical annotation. Level 1A clinical annotations must also be supported by at least one publication in addition to a clinical guideline or drug label with variant-specific prescribing guidance.
PharmGKB	RCV001787378	SCV002031228	drug response	tobramycin response - Toxicity	2021-06-15	reviewed by expert panel	curation	PharmGKB Level of Evidence 1A: Level 1A clinical annotations describe variant-drug combinations that have variant-specific prescribing guidance available in a current clinical guideline annotation or an FDA-approved drug label annotation. Annotations of drug labels or clinical guidelines must give prescribing guidance for specific variants (e.g. CYP2C9*3, HLA-B*57:01) or provide mapping from defined allele functions to diplotypes and phenotypes to be used as supporting evidence for a level 1A clinical annotation. Level 1A clinical annotations must also be supported by at least one publication in addition to a clinical guideline or drug label with variant-specific prescribing guidance.
ClinGen Mitochondrial Disease Nuclear and Mitochondrial Variant Curation Expert Panel, ClinGen	RCV003153300	SCV003842278	pathogenic	Mitochondrial disease	2022-12-15	reviewed by expert panel	curation	The m.1555A>G variant in MT-RNR1 has been reported in more than 65 individuals with primary mitochondrial disease, and the only consistent reported feature in affected individuals was hearing loss (PS4; PMIDs: 7689389, 1613771, 8285309, 8414970, 9111378, 9040738, 9490575, 9831149, 10661905, 12031626, 12920080, 16935512, 20123042, 22317974, 23357420, 24252789, 11870684). Some individuals with this variant have normal hearing, others have hearing loss following aminoglycoside exposure, and others have hearing loss and no known aminoglycoside exposure. Age of onset of hearing loss ranged from infancy (after aminoglycoside exposure) to adulthood. Hearing loss has been reported to be variable, stable in some individuals and progressive in others. Several reports of individuals receiving cochlear implants had good outcomes (PMIDs: 9831149, 16935512, 24252789). While most affected individuals have this variant present at homoplasmy, there have been some reports of heteroplasmic occurrences in those with hearing loss. There are isolated reports of individuals with this variant having other medical concerns, however there is not sufficient evidence currently that this variant was causative of these other concerns. These concerns include chronic progressive external ophthalmoplegia and myopathy (PMID: 11870684), cardiomyopathy (PMIDs: 28104394, 24252789), neural tube defect (PMID: 10661905), hypertension (PMID: 22317974), type 2 diabetes (PMID: 23357420), Parkinson disease (abstract only, Shoffner et al., 1996), autism spectrum disorder and intellectual disability (PMID: 29340697), and Leigh syndrome (PMID: 32867169). There are no de novo occurrences of this variant reported to our knowledge. Many extended families have been reported in the medical literature however the variant was present at homoplasmy in both affected and unaffected family members, thus preventing consideration for PP1. The computational predictor HmtVAR predicts it to be pathogenic score of 1 (PP3). This variant is present in the healthy population, which is to be expected given the known reduced penetrance of this variant. Several studies in patient cells (PMIDs: 8817331, 9915970), cybrids (PMIDs: 8687424, 11230176), and single fiber testing (PMID: 9915970) support the functional impact of this variant (PS3_moderate). This variant meets criteria to be classified as likely pathogenic however this Expert Panel elected to modify the classification to pathogenic given the overwhelming evidence of pathogenicity. Furthermore, the mitochondrial DNA variant specifications are known to not be optimized for pathogenic variants that tend to be homoplasmic in nature and/or have reduced penetrance. This classification was approved by the NICHD/NINDS U24 ClinGen Mitochondrial Disease Variant Curation Expert Panel on December 15, 2022. Mitochondrial DNA-specific ACMG/AMP criteria applied (PMID: 32906214): PS4, PP3, PS3_supporting.
Laboratory for Molecular Medicine, Mass General Brigham Personalized Medicine	RCV000844677	SCV000205457	pathogenic	Rare genetic deafness	2013-04-29	criteria provided, single submitter	clinical testing	The m.1555A>G variant in MTRNR1 has been reported in many individuals with heari ng loss (often after exposure to aminoglycosides) and segregated in many affecte d matrilineal relatives (Prezant 1993, Pandya 1997, Usami 1997). The variant ha s been identified in 0.6-12% of hearing impaired individuals (Chen 2011, Yelvert on 2013), in contrast to 0.1-0.3% of the general population (Bitner-Glindzicz 20 09, Rahman 2012, Wang 2011, Wu 2011). Individuals with this variant usually pass newborn hearing screen, but develop aminoglycoside-induced or late-onset progre ssive hearing loss (Usami 2000, Lu 2009, Lu 2010). The penetrance is incomplete, but higher with aminoglycoside exposure than without, and the clinical manifest ation is influenced by the degree of heteroplasmy, environmental factors, haplog roup background, and other genetic modifiers (Lu 2010). This variant is in a reg ion of the 12S rRNA gene in which aminoglycosides are known to bind, and in whic h aminoglycoside resistance mutations have been described in other species. Alt hough this variant is present in other primate species, it has been shown that c ells with this variant are susceptible to aminoglycosides (Pacheu-Grau 2011). I n summary, this variant meets criteria to be classified as pathogenic based upon the over-representation of the variant in individuals with aminoglycoside-induc ed hearing loss, segregation in affected matrilineal relatives, and functional s tudies. ACMG/AMP Criteria applied: PS4, PP1_Strong, PS3_Supporting
Center for Pediatric Genomic Medicine, Children's Mercy Hospital and Clinics	RCV000224935	SCV000280682	pathogenic	not provided	2014-08-26	criteria provided, single submitter	clinical testing
Medical Genetics Summaries	RCV000722074	SCV000853256	drug response	Gentamicin response	2018-08-01	criteria provided, single submitter	curation	Individuals who have the m.1555A>G variant are at risk of gentamicin-induced hearing loss. A single, therapeutic, dose of gentamicin may result in moderate to profound hearing loss that is bilateral and irreversible.
Illumina Laboratory Services, Illumina	RCV000010255	SCV004101324	pathogenic	Mitochondrial non-syndromic sensorineural hearing loss	2023-09-13	criteria provided, single submitter	clinical testing	The MT-RNR1 m.1555A>G mitochondrial variant is widely reported in the literature in individuals with mitochondrial nonsyndromic hearing loss and deafness. Across a selection of the literature, the variant has been reported in at least 16 individuals with hearing loss (PMID: 7689389; 8285309; 9040738; 8800928; 9490575; 12920080; 20301595). Some individuals with this variant have normal hearing, others have hearing loss following aminoglycoside exposure, and others have hearing loss and no known aminoglycoside exposure. Whilst this variant is present in a homoplasmic state in most affected individuals, the level of heteroplasmy of this variant shows a significant correlation with the clinical signs the severity and onset of disease in at least seven unrelated families (PMID: 12920080; 22475488). Cybrid studies consistently demonstrate that the m.1555A>G variant reduces mitochondrial translation and cell growth (PMID: 8687424; 11230176). Additional functional studies in patient cells and single fiber testing support the functional impact of this variant (PMID: 8817331; 9915970) Multiple lines of computational evidence including MitoTIP and HmtVar suggest this variant may have a deleterious effect on the function of this rRNA. Based on the available evidence, the m.1555A>G variant is classified as pathogenic for mitochondrial nonsyndromic hearing loss and deafness.
OMIM	RCV000010254	SCV000030478	pathogenic	Aminoglycoside-induced deafness	2008-12-26	no assertion criteria provided	literature only
OMIM	RCV000010255	SCV000030479	pathogenic	Mitochondrial non-syndromic sensorineural hearing loss	2008-12-26	no assertion criteria provided	literature only
OMIM	RCV000010256	SCV000030480	pathogenic	Restrictive cardiomyopathy	2008-12-26	no assertion criteria provided	literature only
GeneReviews	RCV000010255	SCV000172231	pathogenic	Mitochondrial non-syndromic sensorineural hearing loss	2018-06-14	no assertion criteria provided	literature only
Donald Williams Parsons Laboratory, Baylor College of Medicine	RCV000505667	SCV000599977	pathogenic	Aminoglycoside-induced deafness; Mitochondrial non-syndromic sensorineural hearing loss	2014-02-27	no assertion criteria provided	research	This variant has been previously reported as disease-causing. It was an incidental finding in our study, in a 4-month-old female with kaposiform hemangioendothelioma. There was 65% heteroplasmy, and it was not detected in the mother, although heteroplasmy below 20% may not be detectable.
Equipe Genetique des Anomalies du Developpement, Université de Bourgogne	RCV000010254	SCV000993414	drug response	Aminoglycoside-induced deafness	2018-09-25	no assertion criteria provided	research
Diagnostics Centre, Carl Von Ossietzky University Oldenburg	RCV003445067	SCV004174183	likely pathogenic	Hearing loss, sensorineural, autosomal-mitochondrial type	2023-10-24	no assertion criteria provided	clinical testing	The variant MT-RNR1:n.908A>G, m.1555A>G is located in the 12S rRNA gene (MT-RNR1) and results from an adenine to guanine at nucleotide position 1555. It has been described in numerous cases with mitochondrial non-syndromic hearing loss (PMID: 7689389, 1613771, 8285309, 8414970, 9111378, 9040738, 9490575, 9831149, 10661905, 12031626, 12920080, 16935512, 20123042, 22317974, 23357420, 24252789, 11870684). Although the variant is present at homoplasmy in unaffected individuals, multiple individuals harboring the variant were reported to have hearing loss after amynoglycoside exposure. Non amynoglycoside exposure-related loss hering have been also reported. Age of onset of hearing loss ranged from infancy (after aminoglycoside exposure) to adulthood. Overall, aminoglycoside-based antibiotic treatments are known to increase the risk of hearing loss in carriers of this alteration (PMID: 29805548, 25515069). Multiple studies provide experimental evidences supporting a deleterious functional effect of the variant (PMID: 11230176, 8817331, 8687424). The variant is not considered rare in the overall population (MAF 0.1% for homoplasmy in gnomAD V3.1). The ClinGen Mitochondrial Disease Nuclear and Mitochondrial Variant Curation Expert Panel suggest to classify of Pathogenic (Clinvar: 9628). Based on available evidence, the variant is classified as Likely Pathogenic.