PKAN: A Rare Inherited Brain Condition in Children and Young Adults — and Why the Eye of the Tiger Matters

The eye of the tiger sign is a distinctive pattern seen on a specific type of brain MRI called T2-weighted imaging. In the globus pallidus a small, important movement-control structure deep in the brain PKAN causes a bright central spot surrounded by a dark ring. On the MRI image, this combination resembles the eye of a tiger, with the dark ring as the pupil and the bright centre as the reflection. The dark ring is caused by iron-laden tissue, and the bright centre reflects specific changes in the tissue caused by the disease process. This pattern is so characteristic of PKAN that when it is found in a child with progressive movement problems, it is a powerful indicator of the diagnosis. Confirming PKAN requires additional genetic testing. At KIMS Neuroscience, Hyderabad, our team is experienced in identifying and interpreting this finding.

Yes — PKAN is an inherited condition caused by mutations in the PANK2 gene, inherited in an autosomal recessive pattern. Both parents are carriers they each carry one mutated copy of the gene but are unaffected themselves. For every pregnancy between two carriers, there is a 25% chance the child will inherit both mutated copies and develop PKAN. Siblings of an affected child each have a 25% chance of also being affected, a 50% chance of being a carrier, and a 25% chance of being completely unaffected. Testing siblings even those with no symptoms is strongly recommended after a PKAN diagnosis. Genetic counselling and testing for the whole family is available at KIMS Neuroscience, Hyderabad.

Yes — two options are available once the specific PANK2 mutations in your family have been identified. Prenatal testing examining cells from the developing baby during pregnancy (by amniocentesis or chorionic villus sampling) can determine whether the baby has inherited both mutated copies. Preimplantation genetic testing (PGT) testing embryos created through IVF in a laboratory before they are transferred to the womb allows only unaffected embryos to be selected for implantation. These options should be discussed with our clinical genetics team at KIMS before planning a future pregnancy.

Status dystonicus is a medical emergency that can occur in PKAN and other severe dystonia conditions. It is a prolonged, severe, generalised episode of dystonic contractions across the whole body that does not resolve on its own. The muscles of the whole body go into intense, sustained spasm simultaneously. This is dangerous because the muscle contractions generate intense heat the body temperature rises and can cause muscle breakdown and kidney damage. Signs to watch for: a severe dystonic episode that is much worse than usual and is not settling, the child's body feeling very hot, the child in extreme distress and unable to relax their muscles, or the child becoming drowsy or unresponsive during the episode. This is a medical emergency. Call 040-46324365 immediately.

No — DBS does not cure PKAN or stop the underlying iron accumulation from progressing. But it can significantly reduce the severity of dystonia in carefully selected patients improving comfort, reducing pain, and in some cases improving function. The results vary between patients: some experience dramatic improvement in dystonia that fundamentally changes their quality of life; others have a more modest response. DBS is generally considered for PKAN patients whose dystonia is severely disabling causing persistent pain, preventing comfortable positioning, or resulting in recurrent status dystonicus and where medical management has not provided adequate control. The KIMS Neuroscience team's team at KIMS Neuroscience performs a thorough multidisciplinary assessment before any DBS decision, and the family is fully involved in the process.

Wilson's disease is a treatable condition in which copper not iron accumulates abnormally in the brain and liver, causing progressive movement problems that can look very similar to PKAN. It is critically important to exclude Wilson's disease before confirming a PKAN diagnosis because Wilson's disease is directly and effectively treatable with copper-chelating medications early treatment can prevent or even reverse the neurological damage. Simple blood tests (ceruloplasmin level and urine copper) and an eye examination are all that is needed to exclude it. At KIMS Neuroscience, we exclude Wilson's disease as a matter of protocol in every child presenting with unexplained movement problems and basal ganglia changes on MRI.

Speech difficulties in PKAN dysarthria are caused by the dystonia and rigidity affecting the muscles of the mouth, tongue, and throat. Speech therapy, started early, can help children maintain clearer communication for longer working on articulation techniques, pacing, and breath support for speech. As speech becomes progressively harder to understand, augmentative and alternative communication (AAC) tools from picture boards to sophisticated eye-gaze or switch-operated speech-generating devices allow children and young adults to continue expressing themselves. Our speech and language therapist at KIMS introduces these strategies early, because learning to use communication tools takes time and is most effective when started before speech is severely impaired.

PKAN is so rare that peer support networks in India are limited, but the KIMS Neuroscience team can connect your family with international resources including the NBIA Disorders Association, which provides comprehensive information, family support, and research updates for all NBIA conditions including PKAN. Online communities of PKAN families from around the world are active and can be an enormous source of practical advice and emotional support. Our social work team at KIMS also provides guidance on accessing financial support, educational accommodations, and community resources in Hyderabad and across Telangana.