The MNX1 gene encodes a nuclear protein, which contains a homeobox domain and is a transcription factor.  This protein is implicated in the control of gene expression in both developing and adult tissues, and is required for the development of multiple tissues, including the anterior horn regions in the spinal cord, the sacra region, as well as the pancreas.  Recent studies have identified MNX1 as an important factor in beta-cell differentiation and proliferation. 

Mutations in the MNX1 gene result in Currarino syndrome.  Nearly all familial and 30% sporadic cases of Currarino Syndrome carry mutations in the MNX1 gene.  Homozygous MNX1 mutations have been shown to cause permanent neonatal diabetes in humans.  

The MNX1 gene, located on the long arm of chromosome 7, is made up of three exons.  The protein product encoded by the gene is made up of 403 amino acids.  The protein consists of three important regions; a 60-amino acid long homeodomain encoded by exons 2 and 3, a highly conserved 82-amino acid domain upstream of the homeodomain, and a polyalanine repeat region which shows sequence length polymorphism.  The homeodomain in MNX1 is conserved among HLXB9 homologues but not among other homeobox genes. 

More than 80 mutations in this gene, mostly missense and frameshift, have been identified in cases with Currarino Syndrome.  Most of these mutations affect the homeobox directly or indirectly, as they encompass regions either upstream or in the homeobox.  These different mutations produce comparable phenotypes, indicating haploinsufficiency as the most likely mechanism-causing disease.