PIGG variant pathogenicity assessment reveals characteristic features within 19 families.
Genet Med
; 23(10): 1873-1881, 2021 10.
Article
en En
| MEDLINE
| ID: mdl-34113002
PURPOSE: Phosphatidylinositol Glycan Anchor Biosynthesis, class G (PIGG) is an ethanolamine phosphate transferase catalyzing the modification of glycosylphosphatidylinositol (GPI). GPI serves as an anchor on the cell membrane for surface proteins called GPI-anchored proteins (GPI-APs). Pathogenic variants in genes involved in the biosynthesis of GPI cause inherited GPI deficiency (IGD), which still needs to be further characterized. METHODS: We describe 22 individuals from 19 unrelated families with biallelic variants in PIGG. We analyzed GPI-AP surface levels on granulocytes and fibroblasts for three and two individuals, respectively. We demonstrated enzymatic activity defects for PIGG variants in vitro in a PIGG/PIGO double knockout system. RESULTS: Phenotypic analysis of reported individuals reveals shared PIGG deficiency-associated features. All tested GPI-APs were unchanged on granulocytes whereas CD73 level in fibroblasts was decreased. In addition to classic IGD symptoms such as hypotonia, intellectual disability/developmental delay (ID/DD), and seizures, individuals with PIGG variants of null or severely decreased activity showed cerebellar atrophy, various neurological manifestations, and mitochondrial dysfunction, a feature increasingly recognized in IGDs. Individuals with mildly decreased activity showed autism spectrum disorder. CONCLUSION: This in vitro system is a useful method to validate the pathogenicity of variants in PIGG and to study PIGG physiological functions.
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Fosfotransferasas (Aceptor de Grupo Alcohol)
/
Trastorno del Espectro Autista
/
Discapacidad Intelectual
Límite:
Humans
Idioma:
En
Revista:
Genet Med
Asunto de la revista:
GENETICA MEDICA
Año:
2021
Tipo del documento:
Article
País de afiliación:
Canadá