Cognition studies of galactosemia patients

Story

 A 4-year-old female came to clinic to establish care as she had recently moved. She was known to have galactosemia that was diagnosed and treatment begun within days of birth. Overall she had done well but was receiving speech therapy and the parents related that she was a "little behind" other children in general. The parents had previously been told that she would probably need some specific help academically. She had no other medical problems.

The pertinent physical exam showed a well-developed female with normal growth parameters, vital signs and normal examination. The diagnosis of a well-child with galactosemia was made. She already had an appointment with the local geneticist for continued monitoring. A referral was made for continued speech therapy as well as the local school system to start discussing her educational needs and a referral to a developmental pediatrician to better assess her overall developmental needs.

Answer

 Cognition studies of galactosemia patients mainly have been cross-sectional and usually show an overall decrease in cognitive function relative to those without galactosemia, with some continued decrease in cognition with aging. Area of cognition affected include IQ, memory, and executive functioning. However, there are large interindividual differences and few longitudinal studies.

One study in Germany that evaluated individual patients for IQ at 3 times (means 11, 13.6 and 26 years) found that individual's IQ basically stayed the same overtime. Also there were 2 clusters of individuals: those with higher IQ scores continued to have higher IQ scores and those with lower scores continued to have lower scores. The authors looked for potential mechanisms such as time to treatment, treatment compliance, etc. but were not able to identify one and postulate that potential in utero exposure may be part of the cause.

Another study in England evaluated older patients (15-51 years) and found overall lower cognition but with large individual variability. Their data also showed educational attainment correlated with cognitive performance. A health-related quality of life study showed similar results. Galactosemic patients themselves and their parents were surveyed and compared to healthy peers. Patients 1-5 years had more communication and abdominal complaints, those 8-15 years differed in cognitive function and those 16 years and older differed in cognitive function and social function. The overall educational attainment by the galactosemic patients was significantly less than the general population.