| Study/year | Variant(s) and transcript nomenclature | Zygosity and patient count | Hearing phenotype | Evidence caveat |
|---|---|---|---|---|
| Shahin et al., 2006 (Palestinian families) | Legacy: **R347X**, **Q581X**, **G1019R**; reported as c.1039C>T, c.1741C>T, and c.3055G>A in the newly described long isoform; do not translate directly to current NM_001039141.2/.3 HGVS without transcript normalization | 27 affected people in 7 families homozygous for R347X or Q581X; 3 affected people in 2 families compound heterozygous (R347X/Q581X or Q581X/G1019R) | Prelingual, bilateral, symmetric, profound sensorineural hearing loss; normal vision reported | Strong segregation evidence. R347X and Q581X occurred in different endogamous Palestinian communities; ancestral relationships were suggested, but population-wide founder status and prevalence were not established. G1019R was found heterozygously in 1/300 hearing controls (pqac-00000024, pqac-00000062, pqac-00000075) |
| Riazuddin et al., 2006 (Pakistani and Indian families) | Legacy exon-6 alleles: **Q297X, R788X, R1068X, R1117X, D1069fsX1082, R1078fsX1083**; original numbering used the first coding ATG of TRIOBP-6 and should not be presented as current NM_001039141.2/.3 HGVS without remapping | Six truncating alleles cosegregated in **7 consanguineous families**; affected individuals were homozygous and obligate carriers heterozygous | Congenital/prelingual severe-to-profound nonsyndromic hearing loss in 11/12 studied linked families; heterozygous carriers had normal hearing | Strong familial segregation and absence from approximately 300 control DNA samples. Five additional linked families lacked detected TRIOBP mutations, indicating possible missed variants or locus heterogeneity (pqac-00000011, pqac-00000021, pqac-00000073) |
| Pollak et al., 2017 (Polish family) | NM_001039141.2:**c.802_805delCAGG**, p.(Gln268Leufs*610), affecting TRIOBP-4/5; and **c.5014G>T**, p.(Gly1672*), affecting TRIOBP-5 | Compound heterozygous in trans in **3 affected siblings**; each parent was a heterozygous carrier | Bilateral moderate-to-severe sensorineural hearing loss; onset at **3, 4.5, and 12 years**; two siblings showed no deterioration over 2 years; youngest passed newborn screening | Strong segregation but single family. Historical ExAC frequencies were 0.000008 and 0.0006, respectively; proposed residual-isoform explanation for milder disease remains a genotype–phenotype hypothesis (pqac-00000065, pqac-00000077) |
| Zhou et al., 2020 (Chinese family) | NM_001039141.2:**c.1342C>T**, p.(Arg448*) | Homozygous in **2 affected siblings**; both consanguineous parents heterozygous | Congenital severe-to-profound, symmetric hearing loss; no additional symptoms reported | Classified **likely pathogenic** by the authors; historical ExAC allele frequency 0.00002 and South Asian gnomAD frequency reported as 0.0000. HOMER2 and TMC2 findings were VUS and should not be treated as causal (pqac-00000035, pqac-00000074) |
| Tekin et al., 2021 (Afghan family) | NM_001039141.2:**c.1342C>T**, p.(Arg448*) | Homozygous in **3 affected siblings** | Profound sensorineural hearing loss; after unilateral cochlear implantation, aided pure-tone averages were 23–30 dBHL at 1 month; two younger recipients reached up to 77% phoneme identification at 10 months | Independent Afghan family—not the Zhou 2020 Chinese pedigree despite the same allele. Useful treatment evidence is limited to three siblings; earlier implantation appeared more favorable (pqac-00000037, pqac-00000045, pqac-00000047) |
| Zhou et al., 2021 (Chinese family) | NM_001039141.2:**c.1170delC**, p.(Ser391Profs*488), and **c.3764C>G**, p.(Ser1255*) | Compound heterozygous in **1 affected 33-year-old woman**; each healthy parent carried one allele | Isolated bilateral prelingual/congenital profound hearing loss | Both variants were novel and absent from the population databases queried at publication; truncating effects and segregation support causality, but evidence derives from one family and detailed audiometry was unavailable (pqac-00000002, pqac-00000005, pqac-00000034) |
| Margret et al., 2024 (South Indian cohort) | NM_001039141.3:**c.2320C>T**, p.(Arg774Ter) | Homozygous in **1 male proband** with hearing loss and infertility | Hearing loss attributed to TRIOBP; severity details were limited in the extracted report | Ultra-rare in gnomAD (MAF <0.0004%) and predicted deleterious. A separate homozygous **LRGUK** variant was assigned to male infertility; the authors concluded hearing loss and infertility were independent events, not a TRIOBP syndrome (pqac-00000033, pqac-00000061, pqac-00000072) |
| Tlili et al., 2024 (UAE cohort) | **c.3133C>T**, p.(Arg1045Cys); transcript not sufficiently specified in the extracted table for safe NM_001039141.2/.3 normalization | Homozygous in **1 sporadic case** | Moderate-to-severe hearing loss | **Candidate missense finding only**: previously unreported, gnomAD frequency 0.0004364, computationally “possibly damaging/deleterious”; no family segregation or functional validation was reported, so it should not be labeled pathogenic or definitive DFNB28 (pqac-00000009, pqac-00000071) |


*Table: Human TRIOBP findings underlying or proposed for DFNB28, with transcript-nomenclature cautions and evidence strength. The table separates well-segregated pathogenic truncating alleles from recent candidate missense findings lacking validation.*