Symptoms:

Symptoms include dystonia, dysarthria, rigidity, spasticity, hyperreflexia and extensor toe signs

Symptoms typically begin in childhood and are progressive, often resulting in death by early adulthood. Symptoms of PKAN begin before middle childhood, and most often are noticed before ten years of age. Symptoms include:

• dystonia (repetitive uncontrollable muscle contractions that may cause jerking or twisting of certain muscle groups)
• dysphagia & dysarthria due to muscle groups involved in speech being involved
• rigidity/stiffness of limbs
• tremor
• writhing movements
• dementia
• spasticity
• weakness
• seizures (rare)
• toe walking
• retinitis pigmentosa, another degenerative disease that affects the individual’s retina, often causing alteration of retinal color and progressive deterioration of the retina at first causing night blindness and later resulting in a complete loss of vision

Affected Population:

PKAN affects one in 1 million people and is caused by genetic defects.

Genetics

PKAN is inherited and is called an autosomal recessive disorder.

Diagnostics:

Prenatal Testing:

If the disease-causing mutations have been identified in the family, prenatal diagnosis for pregnancies can be done by analyzing DNA extracted from fetal cells in amniocentesis or chorionic villus sampling.

PKAN is suspected when magnetic resonance imaging (MRI) changes are seen in an individual with symptoms typically seen in this disease.

All individuals with PKAN have high levels of brain iron, mainly in the globus pallidus. PKAN has a unique characteristic seen on an MRI. Iron accumulation generally makes the brain look dark on certain (T2-weighted) MRI views. In PKAN, this dark area has a very bright spot in the center, called the ‘eye of the tiger sign. It is rarely seen in other forms of NBIA.

The sign sometimes is absent in the early stages of disease. In the Dominican Republic, where 21 affected individuals have been diagnosed with PKAN and have the same PANK2 mutation, it has been reported that six individuals lacked the ‘eye of the tiger sign’ despite their similarities to others in this group.

Some cases with a purported ‘eye of the tiger’ sign will be found to have Mitochondrial-membrane Protein-Associated Neurodegeneration or MPAN, a different form of NBIA that can look similar to PKAN when comparing scans.

Another hallmark feature is the presence of a movement disorder, including one or more of the following: dystonia, rigidity or choreoanthetosis (twisting and writhing). Other common features include corticospinal tract involvement which is responsible for conducting impulses from the brain to the spinal cord, extensor toe signs that indicate damage to the central nervous system and spasticity, along with retinal degeneration or optic atrophy. Seizures are rare.

MRI scans may reveal the eye of the tiger sign, an abnormal low T2 signal (due to abnormal accumulation of iron) in the globus pallidus.

Symptomatic Treatment:

• Benztropine for rigidity and tremor
• Dopamine
• Baclofen for spasm relief and reduced dystonia
• Chelating agents for excess iron removal

Therapies:

• Speech therapy

Procedures:

• Gastrostomy feeding tube placement for advanced dysphagia

Contact these non-profit organizations to learn more about PKAN and NBIA disorders:

Dana Jones Foundation

ENACH

NBIA Cure

Spoonbill Foundation

Retrophin PKAN Study Update

Clinical Rating Scale for Pantothenate Kinase-Associated Neurodegeneration: A Pilot Study

Deep Brain Stimulation for Pantothenate Kinase-Associated Neurodegeneration

Neurodegeneration with Brain Iron Accumulation: Diagnosis and Management (2015)

Neurodegeneration with Brain Iron Accumulation Disorders Overview (2014)

Related Terms:

Eye of the Tiger

MRI

Iron accumulation

NBIA Disorders

National Organization for Rare Disorders – PKAN