Ornithine transcarbamylase deficiency (OTC deficiency,) is an X-chromosome linked, hereditary metabolic disease caused by pathogenic variants \u2013 or genetic changes \u2013 in the OTC<\/em> gene. This defect leads to the incorrect breakdown of ammonia, which can cause comas and result in severe brain damage in male newborns due to very elevated levels of ammonia in the blood. However, a later onset of the disease and a milder progression is also possible, and it may also affect females.<\/p>\n<\/div> Synonyms:<\/p>\n<\/div><\/div><\/div> OTC deficiency, ornithine carbamoyltransferase deficiency<\/p>\n<\/div><\/div><\/div><\/div> Gene:<\/p>\n<\/div><\/div><\/div> OTC<\/i><\/p>\n<\/div><\/div><\/div><\/div> Gen\u00ade product:<\/p>\n<\/div><\/div><\/div> OTC<\/p>\n<\/div><\/div><\/div><\/div> Function:<\/p>\n<\/div><\/div><\/div> Part of the urea cycle<\/p>\n<\/div><\/div><\/div><\/div> Pattern of inheritance:<\/p>\n<\/div><\/div><\/div> X-chromosomal recessive or X-chromosomal dominant<\/p>\n<\/div><\/div><\/div><\/div> Prevalence:<\/p>\n<\/div><\/div><\/div> Varies from 1:14.000 to 1:77.000 depending on the study<\/p>\n<\/div><\/div><\/div><\/div> Genotype-phenotype correlation<\/p>\n<\/div><\/div><\/div> Missense mutations resulting in neonatal occurrence in hemizygous boys. Affected heterozygous females can also develop symptoms later on.<\/p>\n<\/div><\/div><\/div><\/div> Penetrance:<\/p>\n<\/div><\/div><\/div> Complete in affected hemizygous males<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>
\nBoth nonsense mutations, insertions, and deletions that cause a frameshift as well as single-nucleotide variants lead to a complete loss of OTC function and result in neonatal occurrence.<\/p>\n