Multiple acyl-Coa dehydrogenase deficiency: an underdiagnosed disorder in adults.

Inherited metabolic diseases, as a first presentation in adults, are an under-recognised condition associated with significant morbidity and mortality. Diagnosis is challenging because of non-specific clinical and biochemical findings, resemblance to common conditions such as neuropsychiatric disorders and the misconception that these disorders predominantly affect paediatric populations. We describe a series of patients with multiple acyl-CoA dehydrogenase deficiency (MADD)/MADD-like disorders to highlight these diagnostic challenges.

Hyperammonaemia: review of the pathophysiology, aetiology and investigation.

Acute hyperammonaemia is a medical emergency as it can progress to cerebral oedema, seizures, coma and death. Hepatic encephalopathy secondary to cirrhotic disease or portosystemic shunting are relatively well-known causes, but non-cirrhotic aetiologies of acute hyperammonaemia are less well-known, especially in the emergency department. However, an elevated ammonia is not required to make the diagnosis of hepatic encephalopathy. Although measurement of plasma ammonia is recommended for patients with acute, unexplained, altered mental status, as early identification allows early effective management which may prevent irreversible brain damage, there is currently reduced awareness among physicians of the non-cirrhotic aetiologies of acute hyperammonaemia. Furthermore, measurement of ammonia in patients with cirrhosis has been shown to have low sensitivity and specificity, and not to have altered management in the majority of cases; thus, measurement of ammonia is currently not recommended in guidelines for management of hepatic encephalopathy. We sought to describe the pathophysiology of hyperammonaemia and review the non-cirrhotic causes. This was achieved by review of MEDLINE, PubMed and Web of Science databases to include published English literature within the last 20 years. We also present a framework for investigating the acute non-cirrhotic causes of hyperammonaemia to assist both chemical pathologists and clinicians managing these often challenging cases.

Opportunistic Detection of Phytosterolaemia during Genetic Testing for FH: Case Series and Contextual Review.

BACKGROUND: Homozygous phytosterolaemia, is a rare autosomal recessive disorder which lead to severely elevated plasma levels of plant phytosterols causing an increased risk of coronary artery disease (CAD) and mimics the clinical presentation of familial hypercholesterolaemia(FH). Integration of the genetic variants for homozygous phytosterolaemia into the genetic panel for FH in clinical practice likely increases the detection of milder genetic forms of phytosterolaemia, of which the implications to clinical practice including cascade testing remain unclear. RESULTS: We report three families with pathogenic loss-of-function variants in ABCG5 and/or ABCG8, in which probands were identified incidentally when genetically testing them for FH. The proband of the first family was a 35-year-old man with a homozygous ABCG5 loss-of-function variant (c.1336C > T, p.Arg446*) causing severe phytosterolaemia and premature CAD on cardiac imaging; his younger brother was heterozygous for the same variant with mildly elevated phytosterol levels. The second family included 2 sisters (31 and 29-year-old) with digenic variants in ABCG5 (c.1336C > T, p.Arg446*) and ABCG8 (c.1269G > T, p.Glu423Asp with uncertain significance) with moderately elevated plasma phytosterol levels and premature CAD on cardiac imaging. The third family referred to a 68-year-old man and his 44-year-old daughter who were both heterozygous for a pathogenic ABCG5 variant (c.1166G > A, p.Arg389His), had mild phytosterolaemia and CAD on cardiac imaging. Treatment with ezetimibe alone or in combination with colesevelam reduced elevated plasma sitosterol and campesterol concentrations by 30 to 80%. CONCLUSION: Phytosterolaemia is specific genetic disorder that can mimic FH, cause premature atherosclerosis, and require specific pharmacotherapy. Cascade testing for pathogenic ABCG5/G8 variants can lead to earlier detection and treatment of affected family members.

Medium Chain Acyl CoA Dehydrogenase Deficiency and Eating Disorders: An Underreported Coincidence

Abstract Medium chain acyl-coA dehydrogenase deficiency (MCADD), the most common fatty acid oxidation disorder, has been regarded as a relatively benign condition with low risk of mortality in patients with a known diagnosis, if adequate caloric intake is met. However, inadequate energy provision, as occurs in eating disorders, significantly amplifies the risk of metabolic decompensation. This case series describes four patients with MCADD and a concomitant eating disorder and aims to raise awareness of the potentially under-recognised coexistence of these conditions. All patients were female with signs of disordered eating in adolescence and young adulthood though latency in diagnosis was apparent. Three of the patients had low body mass index (BMI) and the other was overweight. Metabolic decompensation and hospitalisation occurred in three of four patients secondary to extreme risk-taking behaviour with caloric restriction. The coexistence of MCADD and eating disorders is of significant concern, placing the patient at substantial risk of decompensation in an otherwise relatively stable metabolic condition. Awareness of disordered eating in this population is paramount, as early recognition of signs and symptoms of eating disorders in the MCADD population may facilitate prompt intervention and avoidance of morbidity and potential mortality.