Tyrosinemia type II

Presentation

Palmar hyperkeratosis, Plantar Hyperkeratosis, hyperhidrosis, corneal opacity, corneal ulcers.

Pathophysiology

Type II tyrosinemia is caused by a deficiency of the enzyme tyrosine aminotransferase (), encoded by the gene TAT. Tyrosine aminotransferase is the first in a series of five enzymes that converts tyrosine to smaller molecules, which are excreted by the kidneys or used in reactions that produce energy. This form of the disorder can affect the eyes, skin, and mental development. Symptoms often begin in early childhood and include excessive tearing, abnormal sensitivity to light (photophobia), eye pain and redness, and painful skin lesions on the palms and soles. About half of individuals with type II tyrosinemia are also mentally disabled. Type II tyrosinemia occurs in fewer than 1 in 250,000 individuals.

Diagnosis

Diagnosis is made based on elevated plasma tyrosine level with skin or eye lesions.

Treatment

Dietary restrictions of phenylalanine and tyrosine.

References

References

1. (27 November 2017). "The Incidence of Transient Neonatal Tyrosinemia Within a Mexican Population". Journal of Inborn Errors of Metabolism and Screening.
2. (2005). "Andrews' Diseases of the Skin: Clinical Dermatology". Saunders.
3. "Tyrosinemia type 2". Genetic and Rare Diseases Information Center (GARD) – an NCATS Program.
4. (2003). "Fitzpatrick's Dermatology in General Medicine". McGraw-Hill.
5. "Tyrosinemia Type II". Myriad Women's Health.