A particular mutation in the G4.5 (previously known as TAZ) gene, encoding for a protein known as tafazzin, is responsible for a rare X-linked disease known as Barth syndrome, characterised by growth retardation, neutropenia, and, most importantly, skeletal myopathy and cardiomyopathy [10]. The gene discussed is TAFAZZIN; the disease is Decreased total neutrophil count.