Natural History Study for Patients With Nemaline Myopathy in Belgium

The planned functional motor assessments are specific to age and degree of motor impairment. Participants are expected to have varying degrees of motor impairment, for example some will be non-ambulant. There is also a wide range of ages of participants. Therefore, some assessments will not be applicable. Some participants may gain or lose these abilities during the study and the assessments they complete shall be tailored accordingly aiming to reflect their most typical abilities on the day assessed.

Syde is an innovative device intended to be used in a home-based environment. It is composed of two watch-like sensors, each containing a magneto-inertial sensors that record the linear acceleration, the angular velocity, the magnetic field of the movement in all directions.The two watches can be worn as wristwatch or placed near the ankle.

The planned respiratory assessments are tailored to the participant's age and respiratory capacity. Participants are expected to have varying degrees of respiratory impairment, and some assessments may not be applicable to all. As participants may gain or lose respiratory function over the course of the study, the assessments completed will be adapted accordingly to reflect their most typical respiratory abilities on the day of assessment.

The planned bulbar function assessments are age-specific and designed to reflect the participant's typical oral intake abilities. For participants aged 1-17 years, the Children's Eating and Drinking Activity Scale (CEDAS), will be used. For those aged 18 years and older, the Functional Oral Intake Scale (FOIS) will be applied. Both tools are part of a unified 7-item scale validated across paediatric and adult populations, ensuring continuity across age groups.

The Clinical Global Impression (CGI) tool will be used to assess overall disease severity and improvement across three functional domains: Physical Motor Function, Respiratory Function, and Bulbar Function. Assessments are based on clinician judgment using all available clinical data and are conducted by clinicians experienced with the disease under study.

The planned quality of life and functional status assessments are designed to capture the participant's overall well-being and daily functioning, taking into account the wide range of ages and disease severities in the study population. Validated questionnaires appropriate to age and functional level will be used to evaluate aspects such as health-related quality of life, fatigue, and daily activity limitations.

Blood sample collection is usually done annually for NM patients as part of their standard of care. This is usually done by a nurse or a medical doctor according to standard guidelines for blood sampling. During routine blood sampling, additional blood will be collected and up to 20 ml of blood will be taken.