Which are the symptoms of Biotinidase Deficiency?

Biotinidase Deficiency is a rare genetic disorder that affects the body's ability to process biotin, a B-vitamin essential for the metabolism of fats, carbohydrates, and proteins. This condition is caused by a deficiency of the biotinidase enzyme, which is responsible for recycling biotin in the body. Without enough biotinidase enzyme, biotin cannot be properly utilized, leading to a range of symptoms that can vary in severity.

Early-onset symptoms:

• Hypotonia: Infants with biotinidase deficiency often exhibit low muscle tone, resulting in floppy movements and poor head control.


• Seizures: Seizures may occur in some affected infants, typically within the first few months of life.


• Developmental delay: Delayed development is common, with affected children experiencing slower progress in acquiring motor skills, language, and cognitive abilities.


• Recurrent infections: Children with biotinidase deficiency may have a higher susceptibility to infections, particularly respiratory and urinary tract infections.


• Hearing and vision problems: Some individuals may develop hearing loss or vision disturbances, such as optic atrophy or impaired visual acuity.

Late-onset symptoms:

• Neurological symptoms: In individuals with late-onset biotinidase deficiency, neurological symptoms may manifest later in childhood or even adulthood. These can include difficulty with coordination, muscle weakness, numbness or tingling in the extremities, and problems with balance and gait.


• Skin rash: Some individuals may experience a scaly red rash around the eyes, nose, mouth, and genital area.


• Hair loss: Hair thinning or loss may occur in some cases.


• Depression and hallucinations: Rarely, individuals with late-onset biotinidase deficiency may develop psychiatric symptoms, such as depression or hallucinations.

If left untreated:

If biotinidase deficiency is not diagnosed and treated promptly, it can lead to severe complications. These may include:

• Ketoacidosis: Without sufficient biotin, the body cannot properly metabolize fats, leading to the accumulation of toxic byproducts called ketones. This can result in a life-threatening condition called ketoacidosis.


• Respiratory problems: Breathing difficulties may arise due to weak respiratory muscles.


• Neurological damage: Prolonged biotin deficiency can cause irreversible damage to the nervous system, leading to intellectual disability, seizures, and other neurological impairments.

Treatment:

Biotinidase deficiency can be effectively managed with lifelong biotin supplementation. Daily oral doses of biotin can help compensate for the enzyme deficiency and prevent the associated symptoms. Early diagnosis through newborn screening programs allows for early intervention and treatment initiation, significantly improving outcomes for affected individuals.