Expressed in mesodermal tissues. Isoform 1 is exclusively expressed from the paternal allele in all fetal tissues and cell lines examined, whereas isoform 2 is preferentially expressed from the paternal allele in a tissue-type-specific manner. Expressed in the nascent mesoderm of gastrulating embryos. At 7.0 dpc expression detected in both the intraembryonic mesoderm and the extraembryonic mesoderm cells of the amniotic fold. At 8.5 dpc expressed predominantly in the head mesenchyme, allantois, and the mesodermal layer of the amnion, chorion and yolk. In 9.5 dpc embryos highly expressed in the mesenchymal tissues, presomitic paraxial mesoderm, heart and branchial arches. Belongs to the AB hydrolase superfamily.