TWNK

twinkle mtDNA helicase, the group of DNA helicases

Basic information

Region (hg38): 10:100987367-100994403

Previous symbols: [ "IOSCA", "C10orf2" ]

Links

ENSG00000107815 ∙ NCBI:56652 ∙ OMIM:606075 ∙ HGNC:1160 ∙ Uniprot:Q96RR1 ∙ AlphaFold ∙ GenCC ∙ jax ∙ Sfari ∙ GnomAD ∙ Pubmed ∙ ClinVar

Phenotypes

GenCC

Source: genCC

• mitochondrial DNA depletion syndrome 7 (hepatocerebral type) (Supportive), mode of inheritance: AR
• Perrault syndrome (Supportive), mode of inheritance: AR
• autosomal dominant progressive external ophthalmoplegia (Supportive), mode of inheritance: AD
• mitochondrial DNA depletion syndrome, hepatocerebrorenal form (Supportive), mode of inheritance: AR
• mitochondrial DNA depletion syndrome 7 (hepatocerebral type) (Strong), mode of inheritance: AR
• progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant 3 (Strong), mode of inheritance: AD

Clinical Genomic Database

Source: CGD

Condition	Inheritance	Intervention Categories	Intervention/Rationale	Manifestation Categories	References
Mitochondrial DNA depletion syndrome 7 (hepatocerebral type); Perrault syndrome 5	AR	Biochemical	Individuals may have biochemical manifestations, including fasting hypoglycemia responsive to glucose therapy	Audiologic/Otolaryngologic; Biochemical; Cardiovascular; Endocrine; Musculoskeletal; Neurologic; Ophthalmologic; Renal	8133312; 7719341; 10522883; 11431692; 12210792; 16135556; 17921179; 17722119; 18775955; 18971204; 20479361; 20880070; 21519523; 21681116; 21689831; 22353293; 22928142; 23375728; 25355836

ClinVar

This is a list of variants' phenotypes submitted to ClinVar and linked to the TWNK gene.

• not_provided (489 variants)
• Progressive_external_ophthalmoplegia_with_mitochondrial_DNA_deletions,_autosomal_dominant_3 (76 variants)
• Infantile_onset_spinocerebellar_ataxia (68 variants)
• Sensory_ataxic_neuropathy,_dysarthria,_and_ophthalmoparesis (38 variants)
• not_specified (36 variants)
• Autosomal_recessive_cerebellar_ataxia (36 variants)
• TWNK-related_disorder (31 variants)
• Perrault_syndrome_5 (23 variants)
• Hereditary_spastic_paraplegia (18 variants)
• Mitochondrial_disease (9 variants)
• Perrault_syndrome (8 variants)
• Inborn_genetic_diseases (7 variants)
• See_cases (4 variants)
• mitochondrial_hepatopathy (3 variants)
• Mitochondrial_DNA_depletion_syndrome (2 variants)
• Ataxia_Neuropathy_Spectrum_Disorders (2 variants)
• Progressive_external_ophthalmoplegia_with_mitochondrial_DNA_deletions (2 variants)
• Auditory_neuropathy (2 variants)
• EMG:_myopathic_abnormalities (1 variants)
• Abnormal_mitochondria_in_muscle_tissue (1 variants)
• Bilateral_sensorineural_hearing_impairment (1 variants)
• Bilateral_ptosis (1 variants)
• Dysphonia (1 variants)
• Third_degree_atrioventricular_block (1 variants)
• Progressive_external_ophthalmoplegia_with_mitochondrial_DNA_deletions,_digenic (1 variants)
• Depression (1 variants)
• Progressive_external_ophthalmoplegia_with_mitochondrial_DNA_deletions,_autosomal_dominant_1 (1 variants)
• Neuromuscular_dysphagia (1 variants)
• Progressive_external_ophthalmoplegia (1 variants)

Variants pathogenicity by type

Statistics on ClinVar variants can assist in determining whether a specific variant type in the TWNK gene is commonly pathogenic or not. These statistics are base on transcript: NM_000021830.5. Only rare variants are included in the table.

In the table, we include only reliable ClinVar variants with their consequences to MANE Select, Mane Plus Clinical transcripts, or transcripts with TSL equals 1. Click the count to view the source variants.

Warning: slight differences between displayed counts and the number of variants in ClinVar may occur, primarily due to (1) the application of a different transcript and/or consequence by our variant effect predictor or (2) differences in clinical significance: we classify Benign/Likely benign variants as Likely benign and Pathogenic/Likely pathogenic variants as Likely pathogenic.

Effect	Pathogenic	Likely pathogenic	VUS	Likely benign	Benign	Sum
synonymous			11	128		139
missense	17	43	267	17		344
nonsense	4	10				14
start loss						0
frameshift	11	5	4			20
splice donor/acceptor (+/-2bp)	1					1
Total	33	58	282	145	0

Highest pathogenic variant AF is 0.000118335

GnomAD

Source: gnomAD

Gene	Type	Bio Type	Transcript	Coding Exons	Length
TWNK	protein_coding	protein_coding	ENST00000311916	5	7035

pLI Probability LOF Intolerant	pRec Probability LOF Recessive	Individuals with no LOFs	Individuals with Homozygous LOFs	Individuals with Heterozygous LOFs	Defined	p
0.00323	0.997	125727	0	21	125748	0.0000835

	Z-Score	Observed	Expected	Observed/Expected	Mutation Rate	Total Possible in Transcript
Missense	1.61	301	390	0.771	0.0000268	4423
Missense in Polyphen		36	88.758	0.4056		1095
Synonymous	-0.617	166	156	1.06	0.00000928	1464
Loss of Function	3.42	10	30.3	0.330	0.00000258	258

LoF frequencies by population

Ethnicity	Sum of pLOFs	p
African & African-American	0.000275	0.000275
Ashkenazi Jewish	0.000298	0.000298
East Asian	0.000163	0.000163
Finnish	0.0000462	0.0000462
European (Non-Finnish)	0.0000616	0.0000615
Middle Eastern	0.000163	0.000163
South Asian	0.0000654	0.0000653
Other	0.00	0.00

dbNSFP

Source: dbNSFP

• Function: FUNCTION: Involved in mitochondrial DNA (mtDNA) metabolism. Could function as an adenine nucleotide-dependent DNA helicase. Function inferred to be critical for lifetime maintenance of mtDNA integrity. In vitro, forms in combination with POLG, a processive replication machinery, which can use double-stranded DNA (dsDNA) as template to synthesize single-stranded DNA (ssDNA) molecules. May be a key regulator of mtDNA copy number in mammals. {ECO:0000269|PubMed:15167897}.
• Disease: DISEASE: Mitochondrial DNA depletion syndrome 7 (MTDPS7) [MIM:271245]: A severe disease associated with mitochondrial dysfunction. Some patients are affected by progressive atrophy of the cerebellum, brain stem, the spinal cord, and sensory axonal neuropathy. Clinical features include hypotonia, athetosis, ataxia, ophthalmoplegia, sensorineural hearing deficit, sensory axonal neuropathy, epileptic encephalopathy and female hypogonadism. In some individuals liver dysfunction and multi- organ failure is present. {ECO:0000269|PubMed:16135556, ECO:0000269|PubMed:17722119, ECO:0000269|PubMed:17921179, ECO:0000269|PubMed:19853444, ECO:0000269|PubMed:22353293}. Note=The disease is caused by mutations affecting the gene represented in this entry.; DISEASE: Perrault syndrome 5 (PRLTS5) [MIM:616138]: A form of Perrault syndrome, a sex-influenced disorder characterized by sensorineural deafness in both males and females, and ovarian dysgenesis in females. Affected females have primary amenorrhea, streak gonads, and infertility, whereas affected males show normal pubertal development and are fertile. {ECO:0000269|PubMed:25355836}. Note=The disease is caused by mutations affecting the gene represented in this entry.
• Pathway: Mitochondrial biogenesis (Consensus)

Recessive Scores

• pRec: 0.154

Intolerance Scores

• rvis_EVS: -0.78
• rvis_percentile_EVS: 12.97

Haploinsufficiency Scores

• hipred: Y
• hipred_score: 0.775
• ghis: 0.578

Essentials

• essential_gene_gene_trap: N

Mouse Genome Informatics

• Gene name: Twnk
• Phenotype: mortality/aging (the observable characteristics related to the ability of a mammalian organism to live and age that are manifested throughout development and life span); cardiovascular system phenotype (the observable morphological and physiological characteristics of the mammalian heart, blood vessels, or circulatory system that are manifested through development and lifespan); embryo phenotype; cellular phenotype

Gene ontology

• Biological process: mitochondrial DNA replication;DNA unwinding involved in DNA replication;mitochondrial transcription;mitochondrion organization;protein hexamerization;protein homooligomerization;cellular response to glucose stimulus
• Cellular component: mitochondrial matrix;mitochondrial nucleoid
• Molecular function: protease binding;single-stranded DNA binding;ATP binding;5'-3' DNA helicase activity