Tyrosinemia Type II
Description
Tyrosinemia Type II, also known as Richner-Hanhart syndrome, is a rare genetic disorder that affects the body‘s ability to break down the amino acid tyrosine. This leads to a buildup of tyrosine and its byproducts, causing a range of symptoms that primarily affect the skin, eyes, and nervous system. This blog post will delve into the intricacies of Tyrosinemia Type II, covering its causes, signs and symptoms, diagnosis, management, and strategies for families to thrive.
Genes Involved
Tyrosinemia Type II is caused by mutations in the gene encoding the enzyme tyrosine aminotransferase (TAT). This enzyme is essential for breaking down tyrosine. When the gene is mutated, the enzyme is either deficient or non-functional, leading to the buildup of tyrosine.
Recognizing the Signs and Symptoms
Tyrosinemia Type II typically presents itself in infancy or early childhood. Some of the most common signs and symptoms include:
- Skin lesions: These appear as blisters, crusts, or thickened areas, often on the palms of the hands and soles of the feet.
- Eye problems: Corneal clouding, which can affect vision, is a hallmark of the condition.
- Neurological issues: This can manifest as intellectual disability, developmental delays, and seizures.
- Other symptoms: These can include hair loss, brittle nails, and feeding difficulties.
Causes
Tyrosinemia Type II is caused by a genetic mutation inherited from parents. Both parents must carry the gene for the child to develop the condition. If only one parent carries the gene, their children will be carriers but won‘t develop the disorder. However, carriers have a 50% chance of passing the gene to their children.
Inheritance/recurrence risk
Tyrosinemia Type II is inherited in an autosomal recessive pattern. This means that both parents must carry a copy of the mutated gene for their child to inherit the disorder. If both parents are carriers, there is a 25% chance of having a child with Tyrosinemia Type II, a 50% chance of having a carrier child, and a 25% chance of having a child who does not have the condition and is not a carrier.
