This loss of Sox6 also affected striatal connections and dopamine levels, with Sox6 expression significantly reduced in PD patients.[4] Additionally, aldehyde dehydrogenase 1 (ALDH1A1) is expressed in a subset of DA neurons, predominantly located in the ventrolateral SNpc.[5] ALDH1A1 is part of an enzyme family responsible for converting aldehydes into carboxylic acids. This evidence concerns the gene SOX6 and Parkinson disease.