Human metallothionein gene MT1L mRNA is present in several human tissues but is unlikely to produce a metallothionein protein.

A human MT gene from the functional locus on chromosome 16, MT1L, is characterised and shown to produce mRNA in at least four human tissues. This gene is unlikely to produce a metallothionein protein because it contains a termination codon at position 26, by analogy to other human MT1 genes. MT1L cDNA is almost identical to another metallothionein cDNA clone reported recently, MT1R, suggesting that either there are unmapped human metallothionein genes, or that MT1L is polymorphic.