SNP Shot: Genomic Insights

Tyrosine hydroxylase (TH) deficiency is a condition impacting movement, with the severity of symptoms varying significantly from person to person.

A milder form, known as TH-deficient dopa-responsive dystonia (DRD), typically manifests in childhood. Individuals with this form may experience abnormal limb postures and difficulty with coordinated movements like walking or running. Some may also have postural tremors (shaking while holding a position) or involuntary upward eye movements. While movement difficulties may worsen gradually, they generally respond well to medical intervention.

More severe forms of TH deficiency include infantile parkinsonism and progressive infantile encephalopathy. These present shortly after birth and pose a greater challenge for effective treatment.

Infantile parkinsonism presents with delayed motor skill development, such as the ability to sit unassisted or reach for objects. Affected infants may exhibit muscle stiffness, particularly in the limbs, unusual postures, droopy eyelids (ptosis), and involuntary upward eye movements. Autonomic nervous system dysfunction can also occur, leading to constipation, gastroesophageal reflux, and difficulties regulating blood sugar, body temperature, and blood pressure. Intellectual disability, speech impairments, attention deficit disorder, and psychiatric conditions like depression, anxiety, or obsessive-compulsive behaviors may also be present.

Progressive infantile encephalopathy, a rare and severe form of TH deficiency, involves brain dysfunction and structural abnormalities. This results in significant physical and intellectual disabilities.

Inheritance:

The inheritance pattern for this condition is autosomal recessive. This means that both parents, who usually don't exhibit symptoms themselves, must carry a copy of the mutated gene for their child to be affected.