HLCS and Isolated 3-methylcrotonyl-CoA carboxylase deficiency: In addition to PCD and 3-MCCD, there have been some case reports of new mothers diagnosed with the following IEM after positive NBS in their newborns: glutaric acidemia type I [7], holocarboxylase synthetase deficiency [8], maternal Middle-chain acyl-CoA dehydrogenase deficiency [9,10], very long chain acyl-CoA dehydrogenase deficiency [11], combined homocystinuria and methylmalonic aciduria [12] and multiple acyl-CoA dehydrogenation deficiency due to a riboflavin transporter gene defect [13].