Trimethylamine, Trimethylamine-N-oxide, N,N-Dimethylglycine and Dimethylated Sulfur Compounds

Genetic causes of persistent/transient malodor syndromes are often defined as benign metabolic variants or conditions of unclear clinical significance. This is due to no physical features, which results in death without appropriate therapeutic intervention/management or supportive/palliative care. Various publications on malodor syndromes have emphasized the psychosocial implications and highlighted the importance of determining disease etiology. In this chapter, we have summarized metabolic conditions resulting in malodor syndromes and inform on available biochemical testing for trimethylaminuria, methanethiol oxidase deficiency, dimethylglycinuria, and methionine adenosyltransferase deficiency. Proton nuclear magnetic resonance (1H-NMR) spectroscopy, which requires fast, non-laborious sample preparation, has shown its versatility in the diagnosis of malodor syndromes of genetic origin. Furthermore, precursor loading protocols have exhibited benefits in the diagnosis of less severe trimethylaminuria, where random sampling rendered an inconclusive result.