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Evaluation of ADL in patients with Hunter disease using FIM score
Tomomi Kato1, Zenichiro Kato, Izumi Kuratsubo
1Department of Pediatrics, Gifu University Graduate School of Medicine, Yanagido 1-1, Gifu 501-1194, Japan. tomok@gifu-u.ac.jp
Abstract:
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.
Insights
Activities of daily living (ADL) decline with age in severe Hunter disease (MPS II) patients, impacting cognitive function more than motor skills. Attenuated forms show age-appropriate ADL progression.
Area of Science:
- Biochemistry and Genetics
- Lysosomal Storage Diseases
- Pediatric Neurology
Background:
- Mucopolysaccharidosis type II (Hunter disease) is a rare genetic disorder caused by iduronate-2-sulfate sulfatase deficiency.
- Hunter disease presents with variable phenotypes, including severe and attenuated forms, distinguished by the presence or absence of intellectual deterioration.
- Understanding the functional capabilities and daily living activities (ADL) is crucial for managing Hunter disease.
Purpose of the Study:
- To quantitatively assess activities of daily living (ADL) in Japanese patients with Hunter disease.
- To evaluate the impact of disease phenotype (severe vs. attenuated) on ADL progression over time.
- To identify age-related patterns and specific challenges in ADL for individuals with Hunter disease.
Main Methods:
- Utilized a modified Functional Independence Measure (FIM) to assess ADL in 27 Japanese patients with Hunter disease.
- Compared ADL scores between patients with severe and attenuated phenotypes and with control children.
- Analyzed ADL score trends across different age groups, focusing on motor and cognitive components.
Main Results:
- Patients with severe Hunter disease exhibited significantly lower ADL scores compared to controls.
- ADL scores peaked around 5-7 years old and declined thereafter in severe cases, with cognitive scores deteriorating more rapidly.
- Attenuated phenotype patients showed progressive ADL score increases with age, similar to controls, though adult patients did not reach maximum scores.
Conclusions:
- This study provides quantitative ADL data, offering a precise clinical profile of Hunter disease beyond narrative descriptions.
- Distinct age-related ADL trajectories were observed for severe and attenuated Hunter disease phenotypes.
- Understanding specific ADL challenges and their timing is vital for improving patient quality of life and guiding supportive care strategies.
