Dataset Information

Whole genome sequencing of 25 South African individuals with myasthenia gravis

ABSTRACT: This study investigated the genetic basis of an ophthalmoplegic subphenotype of MG (OP-MG) which occurs in a proportion of myasthenics with juvenile symptom onset and African genetic ancestry. This OP-MG subphenotype is characterised by treatment resistant weakness of the extraocular muscles (EOMs) and the pathogenetic mechanism(s) underlying its development is unknown. The aim of this study was to use a hypothesis-generating genome-wide case-control analysis to identify candidate OP-MG susceptibility genes and pathways. Whole genome sequencing (WGS) was performed on 25 AChR-antibody positive myasthenic individuals of African genetic ancestry sampled from the phenotypic extremes: 15 with OP-MG (cases) and 10 individuals with control MG (EOM treatment-responsive).

PROVIDER: EGAS00001003462 | EGA |

REPOSITORIES: EGA

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Publications

Using Whole Genome Sequencing in an African Subphenotype of Myasthenia Gravis to Generate a Pathogenetic Hypothesis.

Nel Melissa M Mulder Nicola N Europa Tarin A TA Heckmann Jeannine M JM

Frontiers in genetics 20190301

Myasthenia gravis (MG) is a rare, treatable antibody-mediated disease which is characterized by muscle weakness. The pathogenic antibodies are most frequently directed at the acetylcholine receptors (AChRs) at the skeletal muscle endplate. An ophthalmoplegic subphenotype of MG (OP-MG), which is characterized by treatment resistant weakness of the extraocular muscles (EOMs), occurs in a proportion of myasthenics with juvenile symptom onset and African genetic ancestry. Since the pathogenetic mech ...[more]

PMID: 30881381

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Project description:Background: Mortality from preeclampsia (PE) and PE-associated morbidities are 3-to 5-fold higher in persons of African ancestry than in those of Asian and European ancestries. The placenta is central to the etiology of PE. However, how and to what extent the placenta contributes to worse PE outcomes in persons of African ancestry is yet to be fully elucidated. Objective: We aimed to identify molecular pathways that are unique or enriched in placentas of parturient persons of African ancestry with PE with severe features (sPE) compared to those of Asian and European ancestry with sPE. Study design: Bulk RNA sequencing was performed on 50 placentas from parturient persons with sPE of African (n=9), Asian (n=18) and European (n=23) ancestries and 73 normotensive controls of African (n=9), Asian (n=15) and European (n=49) ancestries. Results: Metabolism, hormone regulation and hypoxia/angiogenesis genes, previously described to be upregulated in PE, including: LEP, PAPPA2, INHA, FSTL3, FLT1, PHYHIP and ENG, were upregulated in sPE across ancestries, with high expression of FSTL3 being additionally associated with intrauterine growth restriction (p<.0001). Notably, LEP, FLT1 and PHYHIP were more highly upregulated in sPE placentas from parturient persons of African versus Asian ancestry. Genes associated with allograft rejection and adaptive immune response were selectively upregulated in placentas from African ancestry parturitions and not in those of Asian and European ancestries. Among the allograft rejection/adaptive immune response genes, IL3RA was of particular interest because the patient with the highest placental IL3RA level, a woman of African ancestry with IL3RA levels 4.5-fold above the average for African ancestry parturitions with sPE, developed postpartum cardiomyopathy, and was the only patient out of 123, that developed this condition. Interestingly, the sPE patients of Asian and European ancestries with the highest IL3RA levels for their ancestries developed unexplained tachycardia peripartum, necessitating echocardiography in the European ancestry patient. The association between elevated placental IL3RA levels and unexplained tachycardia or peripartum cardiomyopathy was found to be significant in the 50 sPE patients (p=.0005). Conclusions: African ancestry parturitions are associated with higher placental upregulation of metabolism (LEP) and hypoxia/angiogenesis (FLT1) genes, and selective upregulation of allograft rejection/adaptive immune response genes, including IL3RA. High placental expression of IL3RA may predict worse maternal cardiovascular outcomes, including peripartum cardiomyopathy. Studies evaluating placental IL3RA levels in peripartum cardiomyopathy cohorts are therefore warranted, as are broader studies evaluating placental factors in maternal cardiovascular outcomes postpartum.

Dataset Information

Whole genome sequencing of 25 South African individuals with myasthenia gravis

Publications

Using Whole Genome Sequencing in an African Subphenotype of Myasthenia Gravis to Generate a Pathogenetic Hypothesis.

Similar Datasets

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