in varying forms in BTHS patients. A common phenotype is both generalized and local weakness. Weakness is exhibited as overt muscle weakness and increased exertional fatigue due to skeletal myopathy. It worsens when present with the cardiovascular symptoms of Barth syndrome. Additional symptoms of musculoskeletal pathology include hypotonia, delayed motor development, short stature, and facial dysmorphia in varying degrees. Furthermore, it has been shown that a downshift in weight, length, and height relative to the normal population is exhibited in BTHS patients. Treatment for developmental delays have included cornstarch supplementation as an alternative source of glucose. Metabolic deficiencies have been treated by oral arginine and carnitine supplementation, which has been shown to ameliorate cardiac function and muscle weakness in some patients. However, no formal assessment of the utility of carnitine and arginine supplementation has been published, and its uses have only been effective in patients with specific deficiencies. Neurological pathology Cognitive impairments are common in BTHS patients in varying degrees. While a higher incidence of cognitive impairment and mild learning and speech difficulties are often manifested, many BTHS patients have also displayed normal cognitive abilities. This shows the limited neurologic involvement in BTHS, despite tafazzin's crucial roles in brain mitochondrial respiration and normal cognitive function. One study has shown that the brain has a distinct CL composition, with more diverse and less tetralinoleoyl-dependent CL. This composition diminishes the need for CL remodeling, resulting in a less tafazzin-dependent composition. Another study found that the brain has a higher concentration of saturated acyl chains. Finally, the brain has a higher ROS scavenging capability, which allows the circumvention of the harmful effects of ROS. These findings explain the neurological phenotypes in BTHS patients. Metabolic disorders Metabolic disorders in BTHS are exhibited in the form of 3-methylglutaconic aciduria (3-MGA), a condition characterized by increased levels of organic acids in urine, including 3‐methylglutaconic acid, 3‐methylglutaric acid, and 2‐ethyl-hydracrylic acid. While 3-MGA is largely excreted in BTHS patients, some patients have been found to have normal levels of organic acids in urine. Treatment of 3-MGA and metabolic deficiencies have included riboflavin or coenzyme Q10, which have shown significant improvement in patients. Hematologic pathology The major hematologic pathology for BTHS patients is neutropenia, a condition characterized by a decline in total number of neutrophils in circulation with an increase in monocytes and eosinophils and no fluctuations in lymphocytes. Presentation of neutropenia varies from mild to severe, cyclical