<i>FGF14</i> repeat length and mosaic interruptions: modifiers of SCA27B?
Notice bibliographique
Résumé
Abstract Deep intronic FGF14 repeat expansions have been identified as a frequent genetic cause of late-onset cerebellar ataxias, explaining up to 30% of patients. Interruptions between repeats have previously been identified to impact the penetrance in other repeat expansion disorders. Repeat interruptions within FGF14 have yet to be characterized in detail. We utilized long-range PCR, Sanger sequencing, repeat-primed PCR, Nanopore, and PacBio sequencing to distinguish the repeat motifs, mosaicism, and number of repeat interruptions present in FGF14 -related ataxia patients and unaffected individuals. A total of 304 patients with late-onset ataxia and 190 unaffected individuals were previously screened for repeat expansions in the FGF14 gene by long-range PCR, identifying 37 individuals with expanded repeat lengths (≥250 repeats). These, along with three newly identified expansion carriers were included in the present study, and advanced genetic methods were applied to investigate the repeat composition in 27 patients and 13 unaffected individuals. The expansions, based on Nanopore data, ranged from 236 to 486 repeats (SD = 60), with 20 individuals showing repeat interruptions, including complex motifs such as GAG , GAA GGA , GAAGAA A GAA, GAAA A GAAGAA G GAAGAA G GAA, GAAA A GAAGAA G GAA, and GCA GAAGAAGAAGAA. We calculated the longest pure GAA length from the long-read data for all 40 individuals. When comparing the pure GAA tract between patients and unaffected individuals, clusters were apparent based on greater or less than 200 repeats. Five ataxia patients with interruptions still had a remaining pure GAA expansion >200. We observed an association of the pure GAA length with age at onset ( p =0.016, R 2 =0.256). Somatically-incurred mosaic divergent repeat interruptions were discovered that affect motif length and sequence (mDRILS), which varied in number and mosaicism (frequency: 0.37-0.93). The mDRILS correlated with pure GAA length ( p =0.022, R 2 =0.334), with a higher mosaic frequency of interruptions in unaffected individuals compared to patients (unaffected: 0.90; patients: 0.67; p =0.009). We demonstrate that i) long-read sequencing is required to detect complex repeat interruptions accurately; ii) repeat interruptions in FGF14 are mosaic, have various lengths and start positions in the repeat tract, and can thereby be annotated as mDRILS, which iii) enabled us to establish a categorization based on remaining pure GAA repeats quantifying the impact of mDRILS on pathogenicity or age at onset, dependent on the interruption length and position, with high accuracy. Finally, we iv) provide evidence that mosaicism stabilizes pure GAA repeats in interrupted FGF14 repeat expansions.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,002 |
| Intégrité de la recherche | 0,000 | 0,001 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».