Safety and Efficacy of Mutation-targeted Precision Genetic Therapy for Ataxia-Telangiectasia (A-T)

Motor performance as measured by the Bruininks-Oseretsky Test of Motor Proficiency 2nd edition

The Bruininks-Oseretsky Test of Motor Proficiency 2nd edition (BOT-2) is a simple way for therapists to check how your child is developing movement skills. It looks at: * Small hand and finger movements (fine motor) * How quickly and accurately hands are used (dexterity) * Big movements like running or jumping (gross motor) * How well the body works together (coordination) During the test, the child does different activities, and each one is scored. These scores are added up to give both an overall score (out of 200 points) and separate scores for each skill area. The results are then compared to what is typical for children of the same age.

Time frame: Baseline and every 6 months up to 10 years

Performance and goal satisfaction as measured by the Canadian Occupational Performance Measure (COPM)

The Canadian Occupational Performance Measure (COPM) is a test done by an occupational therapist to understand what daily activities are most important to a person and how well they feel they can do them. During the test, the person picks up to five activities they find difficult or want to improve. For each activity, they rate: * How well they can do it * How satisfied they are with their performance Both scores range from 1 to 10 (higher numbers mean better performance or more satisfaction). The scores are then averaged to see overall progress. The main goal is to track improvements over time, especially before and after a therapy or intervention.

Time frame: Baseline and every 6 months up to 10 years

Performance in activities of daily living as measured by the Pediatric Evaluation of Disability Inventory Computer Adaptive Test

The Pediatric Evaluation of Disability Inventory - Computer Adaptive Test (PEDI-CAT) is a questionnaire filled out by parents or caregivers. It helps us understand how a child is doing in everyday life. It looks at four areas: * Daily activities (like eating, dressing, and personal care) * Mobility (how a child moves around) * Social/cognitive (how a child plays, communicates, and learns) * Responsibility (how much a child can manage tasks at home or in the community) The test is "adaptive," meaning the questions change depending on how you answer, so it fits your child's abilities. Each area gets a score from 0 to 100, with higher scores meaning better functional ability.

Time frame: Baseline and every 6 months up to 10 years

Visual-motor function as measured by the Beery-Buktenica Developmental Test of Visual Motor Integration

The Beery-Buktenica Developmental Test of Visual-Motor Integration (Beery-VMI) is a test often given by occupational therapists to see how well a child's eyes and hands work together. During the test, the child copies shapes and designs that get harder as the test goes on. Sometimes the child may also be asked to find differences between pictures or match patterns. The results show: * A standard score with a range of 45 to 155; higher scores indicate a better performance * A percentile score, which shows what percentage of children the same age scored lower. This helps parents and therapists see how the child's coordination and fine motor skills are compared to others their age.

Time frame: Baseline and every 6 months up to 10 years

Neurodevelopmental function, as measured by the Leiter International Performance, third edition

The Leiter International Performance Scale-3 (Leiter-3) is a test that measures thinking and problem-solving skills. It is especially helpful for children or adults who have speech, language, or learning difficulties, or for those who do not speak English. The test looks at areas such as: * Problem-solving and reasoning * Attention and memory Visual and spatial skills (understanding shapes, patterns, and space) The results include an IQ score (higher scores mean stronger skills). Subtest scores range from 0 to 20 and composite scores range from 30 to 170; higher scores indicate a better outcome. This helps show how a person's thinking skills compare to others their age.

Time frame: Baseline and yearly up to 10 years

Neurodevelopmental function, as measured Wechsler Intelligence Scale for Children, fifth edition

he Wechsler Intelligence Scale for Children - Fifth Edition (WISC-V) is a test that measures different areas of a child's thinking and learning. It looks at skills such as: * Understanding and using language (verbal comprehension) * Solving puzzles and understanding visual information (visual-spatial) * Problem-solving and reasoning (fluid reasoning) * Remembering information (working memory) * How quickly the brain processes information (processing speed) Subtests have scaled scores with a range of 1 to 19 and composites have standard scores with a range from 45 to 155; higher scores indicate a better outcome. The test gives a Full Scale IQ (FSIQ) score, which shows a child's overall level of thinking skills. Higher scores mean stronger abilities.

Time frame: Baseline and yearly up to 10 years

Neurodevelopmental function, as measured by the Vineland Adaptive Behavior Scale

The Vineland Adaptive Behavior Scales, Third Edition (Vineland-3) is a test that measures how a child or adult manages everyday life skills, also called adaptive behaviors.It looks at areas such as: * Communication (understanding and using language) * Daily living skills (self-care, getting dressed, eating) * Socialization (interacting with others) * Motor skills (movement and coordination) Subtests are calculated as v-Scale scores with a possible range of 1 to 19. Composite scores are Standard Scores with a range of 20 to 140. Higher scores indicate a better outcome Growth scale values (GSVs) describe the participant's absolute level of performance on a test. Range is 10 to 220. Higher scores indicate better performance The results are turned into scores that show how well a person is functioning in daily life. Higher scores mean stronger everyday skills.

Time frame: Baseline and yearly up to 10 years

Motor performance through digital wearable actigraphs

Digital actigraphs are small motion sensors that track how a person moves during daily life. They are often used in people with movement disorders, like ataxia and ataxia-telangiectasia. In this study, participants will wear one sensor on the wrist and one on the ankle for one week at a time. The information collected will show how a person moves during everyday activities. These results will then be compared to others with ataxia-telangiectasia who are not receiving treatment.

Time frame: Baseline and every 12 weeks up to 10 years