Phospholipid abnormalities in children with Barth syndrome.
OBJECTIVE
We sought to identify characteristic lipid abnormalities in patients with Barth syndrome (BTHS) and to correlate the lipid profile to phenotype and genotype.


BACKGROUND
Barth syndrome typically includes cardiomyopathy, skeletal myopathy, neutropenia, growth retardation, and 3-methylglutaconic aciduria, and it is commonly associated with mutations in the tafazzin (TAZ) gene, whose products are homologous to phospholipid acyltransferases. However, clinical features of BTHS have also been found in patients with normal TAZ gene.


METHODS
We analyzed molecular species of phospholipids in left and right ventricle, skeletal muscle, platelets, lymphoblasts, and fibroblasts from 19 children with BTHS (positive TAZ mutation), 6 children with BTHS-like syndromes (wild-type TAZ), 4 children with isolated cardiomyopathy (wild-type TAZ), and various controls.


RESULTS
Cardiolipin, the specific lipid found only in mitochondria, was decreased in all tissues from BTHS patients, whereas concentrations of other phospholipids were normal. The molecular composition of cardiolipin was altered in all tissues from BTHS patients. The molecular compositions of phosphatidylcholine and phosphatidylethanolamine were altered in the heart. Cardiolipin abnormalities were only found in children with true BTHS, not in children with BTHS-like disease or with isolated cardiomyopathy. The degree of cardiolipin deficiency was tissue-specific but did not correlate with severity or specific phenotypic expression of BTHS.


CONCLUSIONS
Abnormal cardiolipin is a specific diagnostic marker of cardiomyopathies caused by TAZ mutations. These mutations lead to alterations in the fatty acid composition of several phospholipids, supporting the idea that TAZ encodes a human acyltransferase.
Schlame
Michael
M
Department of Anesthesiology, New York University School of Medicine, New York, New York 10016, USA. michael.schlame@med.nyu.edu
Kelley
Richard I
RI
Feigenbaum
Annette
A
Towbin
Jeffrey A
JA
Heerdt
Paul M
PM
Schieble
Thomas
T
Wanders
Ronald J A
RJ
DiMauro
Salvatore
S
Blanck
Thomas J J
TJ
D000217:Acyltransferases; D001792:Blood Platelets / Q000737:chemistry; D002308:Cardiolipins / Q000032:analysis; D009202:Cardiomyopathies / Q000378:metabolism*; D005347:Fibroblasts / Q000737:chemistry; D005977:Glutarates / Q000652:urine; D006130:Growth Disorders / Q000378:metabolism; D006352:Heart Ventricles / Q000378:metabolism; D008214:Lymphocytes / Q000737:chemistry; D018482:Muscle, Skeletal / Q000378:metabolism; D009135:Muscular Diseases / Q000378:metabolism*; D009154:Mutation; D009206:Myocardium / Q000737:chemistry; D009503:Neutropenia / Q000378:metabolism; D010743:Phospholipids / Q000032:analysis*; D011506:Proteins / Q000235:genetics; D013577:Syndrome; D014157:Transcription Factors
D002308:Cardiolipins; D005977:Glutarates; D010743:Phospholipids; D011506:Proteins; D014157:Transcription Factors; C022034:3-methylglutaconic acid; D000217:Acyltransferases; C108675:TAFAZZIN protein, human