An evaluation of the global health status of the patients by the IGA was performed. IGA consisted of an evaluation of neurological signs and symptoms as neuromotor disorders, posture and deambulation, disturbances of the oro-pharyngeal apparatus, presence of peripheral neuropathy, neurodevelopmental disturbances, intellectual level, and behavior disturbances based only on a subjective judgment of the Investigator on a single scale: a 5-point qualitative scale as:

• very much improved (1),
• slightly improved (2),
• no change (3),
• slightly worsened (4),
• very much worsened (5) was used to assess changes from V4 to V7. The higher the score, the worse the outcome.

An evaluation of ocular motility measured by an ad hoc form was performed at V4 and V7.

At V4 and V7, ocular motility was assessed through a 5-point qualitative scale: very much improved (1), slightly improved (2), no change (3), slightly worsened (4), very much worsened (5).

An evaluation of ocular motility measured by an ad hoc form was performed at V4 and V7.

At V4 and V7, ocular motility was assessed through a 5-point qualitative scale: very much improved (1), slightly improved (2), no change (3), slightly worsened (4), very much worsened (5).

VABS aggregate scale is used.

VABS is divided into 4 adaptive domains and 11 subdomains:

1. Communication: Receptive, Expressive, Written;
2. Daily Living Skills: Personal, Domestic, Community;
3. Socialisation: Interpersonal Relationships, Play & Leisure Time, Coping Skills;
4. Motor Skills: Gross, Fine.

For each *question* in each of the 11 subdomains, score ranges from 0 to 4 (the higher the value the better the outcome):

• 0 = the subject never performs the behaviour without help or reminders;
• 1 = rarely performs (as above);
• 2 = sometimes performs (as above);
• 3 = often performs (as above);
• 4 = almost always performs (as above); The total subdomain score is the sum of each *question* scores and the total domain score is the sum of each subdomains' scores.

Domains min-max interval scores:

0-74 Communication, 0-74 Daily Living Skills, 0-62 Socialization, 0-111 Motor Skills, Sum-of-domains score 0-321(the higher the score, the better the outcome)

VABS aggregate scale is used.

VABS is divided into 4 adaptive domains and 11 subdomains:

1. Communication: Receptive, Expressive, Written;
2. Daily Living Skills: Personal, Domestic, Community;
3. Socialisation: Interpersonal Relationships, Play & Leisure Time, Coping Skills;
4. Motor Skills: Gross, Fine.

For each *question* in each of the 11 subdomains, score ranges from 0 to 4 (the higher the value the better the outcome):

• 0 = the subject never performs the behaviour without help or reminders;
• 1 = rarely performs (as above);
• 2 = sometimes performs (as above);
• 3 = often performs (as above);
• 4 = almost always performs (as above); The total subdomain score is the sum of each *question* scores and the total domain score is the sum of each subdomains' scores.

Domains min-max interval scores:

0-74 Communication, 0-74 Daily Living Skills, 0-62 Socialization, 0-111 Motor Skills, Sum-of-domains score 0-321(the higher the score, the better the outcome)

The effect of ERY-DEX on treatment emergent adverse events was expressed as the number of patients showing at least one TEAE or 1 serious AE

ICARS ia a 100-point semiquantitative scale, which goes from 0 to 100, offering a compartimentalised quantification of 4 subscores: Posture and Gait Disturbances (maximum score = 34), Kinetic Functions (maximum score = 52), Speech Disorders (maximum score = 8), and Oculomotor Disorders (maximum score = 6) for a possible total score of 100 points. The minimum score is 0 (normal), while the maximum score is 100 and corresponds to the worst status of the patient. This means that for each subscale, higher scores indicate higher levels of impairment.

The PP Population includes 18 patients who have been treated according to protocol and fulfill the following criteria:

• compliance with all entry criteria
• absence of major protocol violations
• adequate compliance with trial medication (at most one missed or out-of-window infusion of the study preparation).

An evaluation of the global health status of the patients by the IGA was performed. IGA consisted of an evaluation of neurological signs and symptoms as neuromotor disorders, posture and deambulation, disturbances of the oro-pharyngeal apparatus, presence of peripheral neuropathy, neurodevelopmental disturbances, intellectual level, and behavior disturbances based only on a subjective judgment of the Investigator on a single scale: a 5-point qualitative scale as:

• very much improved (1),
• slightly improved (2),
• no change (3),
• slightly worsened (4),
• very much worsened (5) was used to assess changes from V4 to V7. The higher the score, the worse the outcome.

The ITT Population includes all 22 patients enrolled into the study.

An evaluation of the global health status of the patients by the IGA was performed. IGA consisted of an evaluation of neurological signs and symptoms as neuromotor disorders, posture and deambulation, disturbances of the oro-pharyngeal apparatus, presence of peripheral neuropathy, neurodevelopmental disturbances, intellectual level, and behavior disturbances based only on a subjective judgment of the Investigator on a single scale: a 5-point qualitative scale as:

• very much improved (1),
• slightly improved (2),
• no change (3),
• slightly worsened (4),
• very much worsened (5) was used to assess changes from V4 to V7. The higher the score, the worse the outcome.

The PP Population includes 18 patients who have been treated according to protocol and fulfill the following criteria:

• compliance with all entry criteria
• absence of major protocol violations
• adequate compliance with trial medication (at most one missed or out-of-window infusion of the study preparation).

An evaluation of ocular motility measured by an ad hoc form was performed at V4 and V7.

At V4 and V7, ocular motility was assessed through a 5-point qualitative scale: very much improved (1), slightly improved (2), no change (3), slightly worsened (4), very much worsened (5).

The ITT Population includes all 22 patients enrolled into the study.

An evaluation of ocular motility measured by an ad hoc form was performed at V4 and V7.

At V4 and V7, ocular motility was assessed through a 5-point qualitative scale: very much improved (1), slightly improved (2), no change (3), slightly worsened (4), very much worsened (5).

The PP Population includes 18 patients who have been treated according to protocol and fulfill the following criteria:

• compliance with all entry criteria
• absence of major protocol violations
• adequate compliance with trial medication (at most one missed or out-of-window infusion of the study preparation).

VABS aggregate scale is used.

VABS is divided into 4 adaptive domains and 11 subdomains:

1. Communication: Receptive, Expressive, Written;
2. Daily Living Skills: Personal, Domestic, Community;
3. Socialisation: Interpersonal Relationships, Play & Leisure Time, Coping Skills;
4. Motor Skills: Gross, Fine.

For each *question* in each of the 11 subdomains, score ranges from 0 to 4 (the higher the value the better the outcome):

• 0 = the subject never performs the behaviour without help or reminders;
• 1 = rarely performs (as above);
• 2 = sometimes performs (as above);
• 3 = often performs (as above);
• 4 = almost always performs (as above); The total subdomain score is the sum of each *question* scores and the total domain score is the sum of each subdomains' scores.

Domains min-max interval scores:

0-74 Communication, 0-74 Daily Living Skills, 0-62 Socialization, 0-111 Motor Skills, Sum-of-domains score 0-321(the higher the score, the better the outcome)

The ITT Population includes all 22 patients enrolled into the study.

VABS aggregate scale is used.

VABS is divided into 4 adaptive domains and 11 subdomains:

1. Communication: Receptive, Expressive, Written;
2. Daily Living Skills: Personal, Domestic, Community;
3. Socialisation: Interpersonal Relationships, Play & Leisure Time, Coping Skills;
4. Motor Skills: Gross, Fine.

For each *question* in each of the 11 subdomains, score ranges from 0 to 4 (the higher the value the better the outcome):

• 0 = the subject never performs the behaviour without help or reminders;
• 1 = rarely performs (as above);
• 2 = sometimes performs (as above);
• 3 = often performs (as above);
• 4 = almost always performs (as above); The total subdomain score is the sum of each *question* scores and the total domain score is the sum of each subdomains' scores.

Domains min-max interval scores:

0-74 Communication, 0-74 Daily Living Skills, 0-62 Socialization, 0-111 Motor Skills, Sum-of-domains score 0-321(the higher the score, the better the outcome)

The PP Population includes 18 patients who have been treated according to protocol and fulfill the following criteria:

• compliance with all entry criteria
• absence of major protocol violations
• adequate compliance with trial medication (at most one missed or out-of-window infusion of the study preparation).

The effect of ERY-DEX on treatment emergent adverse events was expressed as the number of patients showing at least one TEAE or 1 serious AE

The SP includes the 22 patients who have received at least one dose of planned trial treatment.