Tetrahydrobiopterin deficiency is indicated at least in tetrahydrobiopterin deficiency caused by GTPCH deficiency or PTPS deficiency. This condition is very rare; approximately 600 cases have been reported worldwide. In most parts of the world, only 1% to 2% of all infants with high phenylalanine levels have this disorder. In Taiwan, about 30% of newborns with elevated levels of phenylalanine have a deficiency of THB. Subclinical deficiency can be found in individuals with poor diet (including low intake of folate or vitamin C) or genetic mutations in the MTHFR genes, which are involved in BH4 synthesis and recycling. Tetrahydrobiopterin deficiency Tetrahydrobiopterin deficiency (THBD,
Vitamin A a result of alcohol consumption during pregnancy is the elucidated mechanism for fetal alcohol syndrome and is characterized by teratogenicity closely matching maternal vitamin A deficiency. A 2012 systematic review found no evidence that beta-carotene or vitamin A supplements increase longevity in healthy people or in people with various diseases. A meta-analysis of 43 studies showed that vitamin A supplementation of children under five who are at risk of deficiency reduced mortality by up to 24%. However, a 2016 Cochrane review concluded there was not evidence to recommend blanket Vitamin A supplementation for all infants between one and six months