Purification of electron transfer flavoprotein from pig liver mitochondria and its application to the diagnosis of deficiencies of acyl-CoA dehydrogenases in human fibroblasts.

Medium chain acyl-CoA dehydrogenase (MCAD) and long chain acyl-CoA dehydrogenase (LCAD) deficiency are defects of mitochondrial beta-oxidation. The method of choice to measure specifically acyl-CoA dehydrogenase activity in human tissues uses purified electron transfer flavoprotein (ETF). We describe a simple and optimized method of purification allowing isolation of ETF with a degree of purity never reported so far. An assay for acyl-CoA dehydrogenase activity in cultured skin fibroblasts was developed using microquantities of electron transfer flavoprotein and substrate. MCAD deficiency was demonstrated in fibroblasts from nine patients and LCAD deficiency in fibroblasts from two patients.     

Chronic cardiomyopathy and weakness or acute coma in children with a defect in carnitine uptake.

A defect in intracellular uptake of carnitine has been identified in patients with severe carnitine deficiency. To define the clinical manifestations of this disorder, the presenting features of 15 affected infants and children were examined. Progressive cardiomyopathy, with or without chronic muscle weakness, was the most common presentation (median age of onset, 3 years). Other patients presented with episodes of fasting hypoglycemia during the first 2 years of life before cardiomyopathy had become apparent. A defect in carnitine uptake was demonstrable in fibroblasts and leukocytes from patients. The defect also appears to be expressed in muscle and kidney. Concentrations of plasma carnitine and rates of carnitine uptake in parents were intermediate between affected patients and normal control subjects, consistent with recessive inheritance. Early recognition and treatment with high doses of oral carnitine may be life-saving in this disorder of fatty acid oxidation.     

2-Ketoglutarate dehydrogenase deficiency,a rare cause of primary hyperlactataemia: Report of a new case

Summary Two new familial cases of 2-ketoglutarate dehydrogenase (2-KGD) deficiency are reported: a girl who died at 10 years and a boy, still alive at 4 years, born to consanguineous parents. The cases developed progressively severe encephalopathy with axial hypotonia, psychotic behaviour, pyramidal symptoms and failure to thrive. Both children exhibited permanent lactic acidosis with acute episodes during emotional stress and various infections, associated with elevated lactate/pyruvate (L/P) ratio and slightly decreased ketone body ratio in plasma. In fibroblasts, the L/P ratio was greatly increased in the boy. No respiratory chain complex deficiency could be demonstrated in cultured fibroblasts or in mitochondria isolated from a muscle biopsy performed on the boy. In muscle isolated mitochondria, a progressive decrease of the rate of glutamate oxidation was observed after ADP addition; the rate of 2-ketoglutarate oxidation was low in the absence of ADP and did not increase after ADP addition. 2-KGD deficiency was demonstrated in fibroblasts from both children and in the boy's muscle and myoblasts. The 2-KGD complex is composed of three separate enzymes: E1, E2 and E3. We could demonstrate in our patient that the E1 and E3 subunits were normal, suggesting that the E2 component could be responsible for the defect.     

Cerebrovascular events in Takayasu arteritis: a multicenter case-controlled study

Objectives

Takayasu arteritis (TA) is a giant cell arteritis usually affecting young women and characterized by inflammatory and ischemic signs of large vessel involvement, including extracranial cerebral arteries. The impact of stroke on TA prognosis has not been well evaluated.

Methods

We performed a retrospective multicenter review of patients with definite TA who experienced at least one stroke and compared the findings to 17 matched patients with TA diagnosis without neurological involvement.

Results

Seventeen patients (15 women, median age at stroke diagnosis 44 years) receiving a diagnosis of TA and stroke between 2002 and 2016 in our institution were included, from a cohort of 126 patients suffering from TA (13.5%). At diagnosis, patients from both groups had comparable cardiovascular risk factors. The first cerebrovascular event was ischemic stroke (n = 15) or transient ischemic attack (n = 2). In eight patients, stroke occurred after the TA diagnosis was made. In four patients, stroke occurred after carotid surgery. At the end of follow-up, 59% of patients had a neurological impairment, 35% had a recurrence of stroke, and 24% suffered from epilepsy.

Conclusions

Stroke is a major cause of disability in TA patients. Internal carotid surgery may be performed with caution because of the risk of stroke after the procedure.