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 D deficiency further increasing the risk of fall and bone fractures in adults. Ultraviolet B rays from sunlight is a large source of vitamin D. Fatty fish such as salmon, herring, and mackerel are also sources of vitamin D. Milk is often fortified with vitamin D and sometimes bread, juices, and other dairy products are fortified with vitamin D as well. Many multivitamins now contain vitamin D in different amounts. Vitamin D deficiency is typically diagnosed by measuring the concentration of the 25-hydroxyvitamin D in the blood, which is the most accurate measure of stores of vitamin D in the body. Vitamin