Symptoms
Symptoms of a biotinidase deficiency can appear several days after birth. These include: seizures, hypotonia and muscle/limb weakness, ataxia, paresis, hearing loss, optic atrophy, skin rashes (including seborrheic dermatitis and psoriasis), and alopecia. If left untreated, the disorder can rapidly lead to coma and death.
Biotinidase deficiency can also appear later in life. This is referred to as "late-onset" biotinidase deficiency. The symptoms are similar, but perhaps more mild, because if an individual survives the neonatal period they likely have some residual activity of biotin-related enzymes. Studies have noted individuals who were asymptomatic until adolescence or early adulthood. One study pointed out that untreated individuals may not show symptoms until age 21. Furthermore, in rare cases, even individuals with profound deficiencies of biotinidase can be asymptomatic.
Symptom severity is predictably correlated with the severity of the enzyme defect. Profound biotinidase deficiency refers to situations where enzyme activity is 10% or less. Individuals with partial biotinidase deficiency may have enzyme activity of 10-30%.
Functionally, there is no significant difference between dietary biotin deficiency and genetic loss of biotin-related enzyme activity. In both cases, supplementation with biotin can often restore normal metabolic function and proper catabolism of leucine and isoleucine.
The symptoms of biotinidase deficiency (and dietary deficiency of biotin) can be quite severe. A 2004 case study from Metametrix detailed the effects of biotin deficiency, including aggression, cognitive delay, and reduced immune function.
Read more about this topic: Biotinidase Deficiency
Famous quotes containing the word symptoms:
“A certain kind of rich man afflicted with the symptoms of moral dandyism sooner or later comes to the conclusion that it isn’t enough merely to make money. He feels obliged to hold views, to espouse causes and elect Presidents, to explain to a trembling world how and why the world went wrong. The spectacle is nearly always comic.”
—Lewis H. Lapham (b. 1935)
“Protest, evasion, merry distrust, and a delight in mockery are symptoms of health: everything unconditional belongs in pathology.”
—Friedrich Nietzsche (1844–1900)
“Murderous desire, hatred, distrust are nowadays the accompanying signs of physical illness: so thoroughly have we embodied our moral prejudices.—Perhaps cowardice and pity appear as symptoms of illness in savage ages. Perhaps even virtues might be symptoms.”
—Friedrich Nietzsche (1844–1900)