Intermediate repeat expansions of TBP and STUB1: Genetic modifier or pure digenic inheritance in spinocerebellar ataxias?
Genet Med
; 25(2): 100327, 2023 02.
Article
en En
| MEDLINE
| ID: mdl-36422518
ABSTRACT
PURPOSE:
CAG/CAA repeat expansions in TBP>49 are responsible for spinocerebellar ataxia (SCA) type 17 (SCA17). We previously detected cosegregation of STUB1 variants causing SCA48 with intermediate alleles of TBP in 2 families. This cosegregation questions the existence of SCA48 as a monogenic disease.METHODS:
We systematically sequenced TBP repeats in 34 probands of dominant ataxia families with STUB1 variants. In addition, we searched for pathogenic STUB1 variants in probands with expanded alleles of TBP>49 (n = 2) or intermediate alleles of TBP≥40 (n = 47).RESULTS:
STUB1 variants were found in half of the TBP40-49 cohort. Mirroring this finding, TBP40-49 alleles were detected in 40% of STUB1 probands. The longer the TBP repeat length, the more likely the occurrence of cognitive impairment (P = .0129) and the faster the disease progression until death (P = .0003). Importantly, 13 STUB1 probands presenting with the full SCA48 clinical phenotype had normal TBP37-39 alleles, excluding digenic inheritance as the sole mode.CONCLUSION:
We show that intermediate TBP40-49 alleles act as disease modifiers of SCA48 rather than a STUB1/TBP digenic model. This distinction from what has been proposed before has crucial consequences for genetic counseling in SCA48.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Ataxia Cerebelosa
/
Ataxias Espinocerebelosas
Tipo de estudio:
Prognostic_studies
Límite:
Humans
Idioma:
En
Revista:
Genet Med
Asunto de la revista:
GENETICA MEDICA
Año:
2023
Tipo del documento:
Article
País de afiliación:
Francia