Amniotic fluid odd-chain fatty acids are increased in propionic acidaemia.

Odd-chain (C15 and C17) fatty acids have been reported to accumulate in tissues and body fluids of patients with propionic and methylmalonic acidaemia. We investigated the occurrence of these substances in amniotic fluid samples. The odd-chain fatty acid levels (expressed as the percentage of total C12-C20 fatty acids) in eight control samples ranged from 3.7 to 12.5 per cent. Three samples from affected propionic acidaemia pregnancies had values of 15.3-22.9 per cent; one methylmalonic acidaemia sample had a normal level of 9.3 per cent. These results supply further evidence of the prenatal accumulation of odd-chain fatty acids in propionic acidaemia.