Any fatal multiple mitochondrial dysfunctions syndrome in which the cause of the disease is a mutation in the NFU1 gene. The disease is multiple mitochondrial dysfunctions syndrome 1 (MONDO_0011582, a Monarch Disease Ontology id). Also known as: NFU1 deficiency, NFU1 fatal multiple mitochondrial dysfunctions syndrome, fatal multiple mitochondrial dysfunctions syndrome caused by mutation in NFU1, multiple mitochondrial dysfunctions syndrome type 1.