Maternal uniparental disomy of chromosome 1 is an uniparental disomy of maternal origin that most likely does not have any phenotypic expression except from cases of homozygosity for a recessive disease mutation for which only mother is a carrier. The disease is maternal uniparental disomy of chromosome 1 (Monarch Disease Ontology id MONDO_0016651). Also known as: UPD(1)mat, maternal uniparental disomy of chromosome type 1.