Peptidase M20 Domain Containing Protein 1 (PM20D1)

PM20D1 belongs to the peptidase M20A family. This domain consists of 4 beta strands and two alpha helices which make up the dimerisation surface of members of the MEROPS peptidase family M20. Loss of activity was due to decreased amounts of aminoacylase I protein. The amount of mRNA for the aminoacylase I was decreased. DNA sequencing of the encoding ACY1 gene showed a homozygous c.1057 C>T transition, predicting a p.Arg353Cys substitution. Both parents were heterozygous for the mutation. The mutation was also detected in 5/161 controls. To exclude the possibility of a genetic polymorphism, protein expression studies were performed showing that the mutant protein had lost catalytic activity.