A Rare Genetic Disorder Found Far from Home
Dr. Nayiar Shahid - 22 January 2026
Dr. Oksana Suchowersky
A neurological disorder once believed to exist almost exclusively in the Caribbean has now been identified thousands of kilometres away in northern Canada. In a new study led by Dr. Oksana Suchowersky and colleagues, researchers report the first confirmed case of Cayman ataxia in an Inuit man living above the Arctic Circle. Published in Parkinsonism and Related Disorders, the discovery challenges long-held assumptions about where rare genetic diseases can appear and how they are diagnosed.
Cayman ataxia is one of the world’s rarest inherited brain disorders. Until recently, most known cases were traced to families from the Cayman Islands, with only a handful reported in Pakistan and Iran. The condition affects the cerebellum, the part of the brain responsible for balance, coordination, and controlled movement. People with Cayman ataxia are born with movement difficulties that remain relatively stable throughout life, making the disorder difficult to diagnose as it is generally thought that genetic disorders are always progressive. These types of cases can be misdiagnosed as cerebral palsy..
Because symptoms do not worsen over time, Cayman ataxia is often mistaken for other neurological conditions. Many individuals are misdiagnosed, and some never receive a clear explanation for their lifelong symptoms.
That is exactly what happened in this new case.
The patient, an Inuit man from northern Canada, had lived his entire life with coordination and balance problems. For decades, the cause of his condition remained unknown. Brain imaging revealed an underdeveloped cerebellum, and a recorded neurological exam showed abnormal eye movements and coordination difficulties typical of Cayman ataxia. Still, standard clinical tests and routine genetic screenings failed to identify the cause.
The breakthrough came when researchers used chromosomal microarray analysis, a form of genetic testing. This revealed a homozygous deletion in the ATCAY gene (Ataxia, Cayman type), a mutation known to cause Cayman ataxia. ATCAY helps guide normal development of the cerebellum, the brain region that controls balance and coordination.
The finding was unexpected. Cayman ataxia had long been considered a geographically isolated disease, largely confined to specific families linked to the Cayman Islands. Identifying the same genetic disorder in a completely different (northern Indigenous) population challenges that assumption and suggests the condition may be more widespread than previously recognized.
The discovery has important implications for medicine
First, it shows that rare genetic diseases are not always restricted to specific regions or populations. Some may exist quietly for generations, remaining undetected without access to advanced genetic tools.
Second, it highlights the growing importance of modern genetic testing in diagnosis.
Without detailed DNA testing such as chromosomal microarray, this patient’s condition would likely have remained unexplained. The study shows how newer technologies can provide answers even after years of uncertainty.
Finally, the findings may change how doctors approach similar cases in the future. Patients with lifelong balance and coordination difficulties may now be considered for Cayman ataxia testing, even without any known connection to the Caribbean. This could lead to more accurate diagnoses, improved care, and deeper insight into rare neurological disorders.
Beyond this single case, the study sends a broader message about rare disease research. Conditions once thought to affect only small, isolated groups may exist quietly in other populations, waiting to be discovered.
By identifying Cayman ataxia far from its known origin, Dr. Suchowersky’s research team has expanded both the scientific map of this disease and our understanding of rare genetic disorders.
Sometimes, major discoveries do not come from finding something new, but from recognizing something already known in an unexpected place.