Evaluation of ADL in patients with Hunter disease using FIM score

MPS type II (Hunter disease) results from deficiency of the lysosomal enzyme iduronate-2-sulfate sulfatase. Two forms of the disease have been recognized, based on absence or presence of progressive intellectual deterioration. This study aimed to assess activities of daily life (ADL) in 27 Hunter disease-affected Japanese patients, using a modified version of the functional independence measure (FIM). Scores of ADL for patients with a severe phenotype were significantly lower than those of control children. Total scores were highest around 5–7 years old, then progressively decreased, and scores <40 were obtained with patients aged 9 years or more. In contrast to motor scores, cognitive scores decreased rapidly, generally reaching a minimum score at around 7 years old. On the other hand, in children with attenuated phenotype, total scores increased progressively with age similar to control children. Two children who had the highest grades at elementary school showed maximum scores. However, all adult patients did not show maximum total scores, and 3 of 4 patients over 25 years old showed decreasing scores. Two children and two adults showed significant lower scores compared with other patients, suggesting an intermediate form from the view of ADL. This study elucidated the precise clinical state of Hunter disease with distinct numerical scores, in addition to previously described narrative data. To maintain the QOL of the patients better, they and their family need to know what specific difficulties they encounter, in which period they encounter them, and what support can fix them. Further ADL investigations with larger populations and/or long-term sequential examination could help the patients and family to understand them well.