Sári was born with a relatively low birth weight (2,200 g) and was a frail baby. It took four years to reach a diagnosis. It turned out that Sári has an ultra-rare genetic disorder, designated by the number of the disease-causing gene variant: HNRNPH2. This is an X-linked neurological developmental disorder which, in Sári’s case, causes delayed cognitive, motor and speech development, hypotonia, feeding difficulties, vision problems, sensory sensitivity and anxiety. The little girl is nearly 6 years old; for the time being, she crawls and says a few words, but she is curious, open-minded and motivated. Her parents are doing everything they can to ensure that Sári can lead as independent and fulfilling a life as possible, and take part in nursery life happily and at ease.