Deafness_Isolated
Gene: FOXI1
Comment on list classification: There is limited evidence for an association of this gene with isolated deafness. There is stronger evidence for an association with biallelic syndromic deafness (distal renal tubular acidosis with deafness), thus this gene is green on the deafness isolated and complex panel.Created: 12 May 2022, 5:21 a.m. | Last Modified: 12 May 2022, 5:21 a.m.
Panel Version: 1.29
Limited evidence - enlarged vestibular aqueduct (EVA) - Conflicting evidence for digenic inheritance (PMID: 17503324, 32447495). Only compelling evidence is double heterozygous mouse model. Original publication is from 2007. Many heterozygous missense reported, but no significant missense constraint in gene.
PMID: 17503324 - this study proposed SLC26A4 c.-103T>C silences FOXI1 transcription in multiple EVA cases, which lead to sequence FOXI1 as a candidate gene. 6 cases with Pendred syndrome and nonsyndromic EVA with missense/in-frame deletion, one case (G258E) also had a SLC26A4 missense (E29Q - LP) with digenic inheritance (both heterozygous parents were unaffected). All FOXI1 variants had reduced transcriptional activity in luciferase assays. G258E - 25 hets in gnomAD v2.1, N161del, G258R - 3 hets gnomAD v2.1, R267Q - 18 hets gnomAD v2.1, G335V - 3 hets gnomAD v2.1. Also, EVA occurs in the Slc26a4+/−; Foxi1+/− double-heterozygous mouse mutant
PMID: 30268946 - 1 heterozygous missense (p.Asp189Asn - 8 hets in gnomAD v2.1) identified in a EVA case. SLC26A4 also screened in this individual.
PMID: 27997596 - 1 EVA proband with a de novo missense (c.519C>A, p.His173Gln) & 1 EVA proband with missense (c.716C>T, p.Pro239Leu - 71 hets gnomAD v2.1) that was paternally inherited. All probands in the study were expected to have recessive disease and were also screened for variants in SLC26A4.
PMID: 22285650 - 716C>T (p.P239L) also identified in a proband with congenital severe SNHL with inner ear malformations, and a normal thyroid phenotype. Negative for SCL26A4 variants
PMID: 23965030 - c.367C > T p.Arg123Trp with SLC26A4 c.2219C > T p.Gly740Val in a case with hearing impairment and either goitre or EVA
PMID: 24860705 - identified a common variant in a Pendred syndrome case when investigating digenic inheritance, c.677C>T p.Thr226Ile - 1059 alleles in gnomAD v2.1 & 4 homozygotes
PMID: 32447495 - c.214C>A p.Pro72Thr (2 hets in gnomAD v2.1) identified in an EVA case with compound het SLC26A4 variants. FOXI1 variant derived from unaffected paternal transmission, which is evidence against digenic inheritance
PMID: 19204907 - this study disputes that SLC26A4 c.-103T>C exterts a pathogenic effect on FOXI1 transcription
Disputed classification by the ClinGen Hearing Loss GCEP, based on publication above - Classification - 09/10/2018Created: 12 May 2022, 5:18 a.m. | Last Modified: 12 May 2022, 5:18 a.m.
Panel Version: 1.28
Mode of inheritance
Other
Phenotypes
enlarged vestibular aqueduct syndrome MONDO:0023069
Publications
Comment on publications: Another six individuals reported in 17503324, though in one digenic inheritance was suggested.Created: 2 Jan 2020, 4:14 a.m. | Last Modified: 2 Jan 2020, 4:14 a.m.
Panel Version: 0.193
Disputed evidence for enlarged vestibular aqueduct PMID: 19204907Created: 3 Jul 2020, 4:26 a.m. | Last Modified: 3 Jul 2020, 4:26 a.m.
Panel Version: 0.358
2 unrelated families and a mouse modelCreated: 31 Dec 2019, 1:09 a.m. | Last Modified: 31 Dec 2019, 1:09 a.m.
Panel Version: 0.65
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
sensorineural deafness and distal renal tubular acidosis
Publications
Phenotypes for gene: FOXI1 were changed from Hearing loss and renal tubular acidosis to enlarged vestibular aqueduct syndrome MONDO:0023069
Gene: foxi1 has been classified as Red List (Low Evidence).
Gene: foxi1 has been classified as Green List (High Evidence).
gene: FOXI1 was added gene: FOXI1 was added to DeafnessIsolated. Sources: Melbourne Genomics Health Alliance Deafness Flagship,Expert Review Green,Victorian Clinical Genetics Services Mode of inheritance for gene: FOXI1 was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: FOXI1 were set to 9843211; 29242249; 17503324 Phenotypes for gene: FOXI1 were set to Hearing loss and renal tubular acidosis