Motor function scales:

- Functional Mobility Scale (FMS). The FMS classifies the functional mobility of children 4-18 years of age taking into account the assistive devices a child might use.

3 items (distances), each of which is rated from 1-6 depending on assistance required, or "C" for crawling or "N" if distance is not completed Maximum score is a 6 for each of the distances (5m, 50m, and 500m)

-Bayley Scale-3 (BSID-3), at the time that version 4 of the Bayley scale (BSID-4) is validated in Spanish, it will be used in the context of the registry.

Bayley Scales of Infant Development III, cognitive scale; raw scores used to reflect change over time and absolute growth (rather than standard scores) Range: Minimum =20 points; Maximum=60 Higher score = better outcome

Vineland Scale-III is designed to measure adaptive behavior of individuals from birth to age 90. The Vineland-II contains 5 domains each with 2-3 subdomains. The main domains are: Communication, Daily Living Skills, Socialization, Motor Skills, and Maladaptive Behavior.

Aberrant behavior scale (ABC-C). The ABC-C is a global behavior checklist that measures drug and other treatment effects in people with developmental disabilities. It is made up of five subscales, including Irritability, Lethargy, Inappropriate Speech, Hyperactivity, and Stereotypy based on 58 items that describe various behavioral problems.

ORCA communication tool (specifically designed for patients with AS). Observed Reported Communication Assessment (ORCA) Tool. Questionnaire designed to be completed by the patients' main carer and records patient communication.

-Leiter-3, Nonverbal Intelligence Scale (for patients with equivalent developmental age greater than 3 years 6 months). Is a totally nonverbal test of intelligence and cognitive abilities. Evaluates nonverbal cognitive, attentional, and neuropsychological abilities, and targets 'typical' as well as 'atypical' children, adolescents, and now adults.

-Childhood Sleep Disorders Scale (Bruni Scale). The SDSC is a 26-item scale developed to assess the presence of sleep difficulties in children within the previous six months.

Divided items into six categories representing some of the most common sleep diffi culties affecting adolescents and children: disorders of initiating and maintaining sleep, sleep breathing disorders, disorders of arousal/nightmares, sleep-wake transition disorders, disorders of excessive somnolence, and sleep hyperhidrosis (nighttime sweating).

The measure is completed by the parent of the child and takes approximately 5-10 min to complete. Item 1 measures the child's average hours of sleep, from 1 ('9 - 11 h') to 5 ('less than 5 h'). Item 2 measures the child's average time to fall asleep, from 1 ('less than 15 min') to 5 ('more than 60 min'). The remaining 24 items are rated on a 5-point Likert scale, from 1 ('Never') to 5 ('Always [daily]').

-Children's Sleep Habits Questionnaire (CSHQ) This questionnaire was designed as a sleep screening instrument for school-aged children that yields final scores across eight subscales: bedtime resistance, sleep resistance, parasomnia, sleep disordered breathing, night-wakings, daytime sleepiness, sleep anxiety, and sleep onset delay, as well as a summative score, called the Total Sleep Disturbance score.

This study will utilize a brief 6-item sleep diary to collect parent-reported sleep variables (e.g., "what time was your child down for the night?").

Proteomic analysis: Ubiquitin proteomics approach. Characterization of ubiquitination by Ube3a, a proteasomal component conserved from yeast (Ddi1) to humans (DDI1 and DDI2).

Electroencephalogram (EEG) to record brain activity of Angelman Syndrome patients over a 4-hour period (e.g., sleep architecture, number and frequency of seizures, background epileptic activity, delta-rhythmicity)