Elsie, aged 18 months, was born with an ultra-rare neurological condition caused by a mutation in the RARB (retinoic acid receptor beta) gene. This mutation is de novo, meaning it is not hereditary, and its effects are progressive. There are fewer than 100 known cases of this condition globally.
The RARB gene, when functioning correctly, helps control vitamin A signalling, which is vital for the proper embryonic development of the eyes, brain, lungs, and spinal cord. Elsie has a visual impairment and is legally classed as blind, though she has some peripheral vision.
For most of her first eight months, Elsie lived in hospitals due to a symptom where she would stop breathing when upset, sometimes for two to three minutes. These episodes, called apneas, still occur but are now shorter and less frequent, often resolved with oxygen from a cylinder.
Born in March 2025, Elsie has been home since February 2026. She is behind in her development and it is not yet known if she will be verbal. She uses her tongue to explore her environment and makes new sounds daily.