Dataset Information

X chromosome inactivation in carriers of Barth syndrome.

ABSTRACT: Barth syndrome (BTHS) is a rare X-linked recessive disorder characterized by cardiac and skeletal myopathy, neutropenia, and short stature. A gene for BTHS, G4.5, was recently cloned and encodes several novel proteins, named "tafazzins." Unique mutations have been found. No correlation between the location or type of mutation and the phenotype of BTHS has been found. Female carriers of BTHS seem to be healthy. This could be due to a selection against cells that have the mutant allele on the active X chromosome. We therefore analyzed X chromosome inactivation in 16 obligate carriers of BTHS, from six families, using PCR in the androgen-receptor locus. An extremely skewed X-inactivation pattern (>=95:5), not found in 148 female controls, was found in six carriers. The skewed pattern in two carriers from one family was confirmed in DNA from cultured fibroblasts. Five carriers from two families had a skewed pattern (80:20-<95:5), a pattern that was found in only 11 of 148 female controls. Of the 11 carriers with a skewed pattern, the parental origin of the inactive X chromosome was maternal in all seven cases for which this could be determined. In two families, carriers with an extremely skewed pattern and carriers with a random pattern were found. The skewed X inactivation in 11 of 16 carriers is probably the result of a selection against cells with the mutated gene on the active X chromosome. Since BTHS also shows great clinical variation within families, additional factors are likely to influence the expression of the phenotype. Such factors may also influence the selection mechanism in carriers.

SUBMITTER: Orstavik KH

PROVIDER: S-EPMC1377557 | biostudies-other | 1998 Nov

REPOSITORIES: biostudies-other

ACCESS DATA

Publications

X chromosome inactivation in carriers of Barth syndrome.

Orstavik K H KH Orstavik R E RE Naumova A K AK D'Adamo P P Gedeon A A Bolhuis P A PA Barth P G PG Toniolo D D

American journal of human genetics 19981101 5

Barth syndrome (BTHS) is a rare X-linked recessive disorder characterized by cardiac and skeletal myopathy, neutropenia, and short stature. A gene for BTHS, G4.5, was recently cloned and encodes several novel proteins, named "tafazzins." Unique mutations have been found. No correlation between the location or type of mutation and the phenotype of BTHS has been found. Female carriers of BTHS seem to be healthy. This could be due to a selection against cells that have the mutant allele on the acti ...[more]

PMID: 9792874

Similar Datasets

Project description:First described in 1983, Barth syndrome (BTHS) is widely regarded as a rare X-linked genetic disease characterised by cardiomyopathy (CM), skeletal myopathy, growth delay, neutropenia and increased urinary excretion of 3-methylglutaconic acid (3-MGCA). Fewer than 200 living males are known worldwide, but evidence is accumulating that the disorder is substantially under-diagnosed. Clinical features include variable combinations of the following wide spectrum: dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), endocardial fibroelastosis (EFE), left ventricular non-compaction (LVNC), ventricular arrhythmia, sudden cardiac death, prolonged QTc interval, delayed motor milestones, proximal myopathy, lethargy and fatigue, neutropenia (absent to severe; persistent, intermittent or perfectly cyclical), compensatory monocytosis, recurrent bacterial infection, hypoglycaemia, lactic acidosis, growth and pubertal delay, feeding problems, failure to thrive, episodic diarrhoea, characteristic facies, and X-linked family history. Historically regarded as a cardiac disease, BTHS is now considered a multi-system disorder which may be first seen by many different specialists or generalists. Phenotypic breadth and variability present a major challenge to the diagnostician: some children with BTHS have never been neutropenic, whereas others lack increased 3-MGCA and a minority has occult or absent CM. Furthermore, BTHS was first described in 2010 as an unrecognised cause of fetal death. Disabling mutations or deletions of the tafazzin (TAZ) gene, located at Xq28, cause the disorder by reducing remodeling of cardiolipin, a principal phospholipid of the inner mitochondrial membrane. A definitive biochemical test, based on detecting abnormal ratios of different cardiolipin species, was first described in 2008. Key areas of differential diagnosis include metabolic and viral cardiomyopathies, mitochondrial diseases, and many causes of neutropenia and recurrent male miscarriage and stillbirth. Cardiolipin testing and TAZ sequencing now provide relatively rapid diagnostic testing, both prospectively and retrospectively, from a range of fresh or stored tissues, blood or neonatal bloodspots. TAZ sequencing also allows female carrier detection and antenatal screening. Management of BTHS includes medical therapy of CM, cardiac transplantation (in 14% of patients), antibiotic prophylaxis and granulocyte colony-stimulating factor (G-CSF) therapy. Multidisciplinary teams/clinics are essential for minimising hospital attendances and allowing many more individuals with BTHS to live into adulthood.

Project description:IntroductionBarth syndrome (BTHS) is a rare X-linked disorder characterized by cardiomyopathy, neutropenia, growth abnormalities, and skeletal myopathy. There have been few studies investigating health-related quality of life (HRQoL) in this population. This study investigated the impact of BTHS on HRQoL and select physiologic measures in affected boys and men.MethodsIn this study, we characterize HRQoL in boys and men with BTHS through cross-sectional analysis of a variety of outcome measures including the Pediatric Quality of Life Inventory (PedsQLTM) Version 4.0 Generic Core Scales, PedsQLTM Multidimensional Fatigue Scale, Barth Syndrome Symptom Assessment, the PROMISTM Fatigue Short Form, the EuroQol Group EQ-5DTM, the Patient Global Impression of Symptoms (PGIS), and the Caregiver Global Impression of Symptoms (CaGIS). For a specific subset of participants, physiologic data were available in addition to HRQoL data.ResultsFor the PedsQLTM questionnaires, 18 unique child and parent reports were analyzed for children aged 5-18 years, and nine unique parent reports were analyzed for children aged 2-4 years. For the other HRQoL outcome measures and physiologic measurements, the data from 12 subjects (age range 12-35 years) were analyzed. Based on parent and child reports, HRQoL is significantly impaired in boys and men with BTHS, especially in school functioning and physical functioning. Parent and child reports of more severe fatigue are significantly correlated with more impaired HRQoL. When exploring the potential relationship between physiology and HRQoL, the CaGIS as a whole for pediatric subjects and individual questionnaire items from the PGIS and CaGIS for pediatric subjects assessing tiredness, muscle weakness, and muscle pain showed the strongest correlations.ConclusionThis study provides a unique characterization of the HRQoL in boys and men with BTHS using a variety of outcome measures, and it highlights the negative impact of fatigue and muscle weakness on HRQoL in BTHS.Trial registry nameA Trial to Evaluate Safety, Tolerability and Efficacy of Elamipretide in Subjects with Barth Syndrome (TAZPOWER). https://clinicaltrials.gov/ct2/show/NCT03098797.Registration Number: NCT03098797.

Dataset Information

X chromosome inactivation in carriers of Barth syndrome.

Publications

X chromosome inactivation in carriers of Barth syndrome.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets