January
4th World Braille day
24th  Moebius Syndrome Awareness day

February
Marfan Awareness Month
AMD/Low Vision Awareness Month
15th International Angleman Day
28th Rare Disease Awareness Day

March
Brain Injury Awareness Month
Developmental Disabilities Awareness Month
Multiple Sclerosis Awareness Month
Cerebral Palsy Awareness Month
Trisomy Awareness Month
4th Fragile X Awareness Day
21st World Down Syndrome Awareness Day
25th Cerebral Palsy Awareness Day
26th Purple day for Epilepsy Awareness Day

April
Autism Awareness Month
Limb loss Awareness Month
2nd Autism Awareness Day

May
Better hearing and speech Awareness Month
Cystic Fibrosis Awareness Month
Huntington's Disease Awareness Month
Muscular Dystrophy Awareness Month
Prader-Willi Syndrome Awareness Month
Tuberous Sclerosis Awareness Month
Williams Syndrome Awareness Month
8th Children's Mental Health Awareness Day
10th Cornelia de Lange Awareness day
12th Fibromyalgia and Chronic Fatigue Syndrome Awareness Day
14th Apraxia Awareness Day
15th Global TSC Awareness Day

June
27th PTSD Awareness Day

August
Spinal Muscular Atrophy Awareness Month

September
Childhood Cancer Awareness Month
Hydrocephalus Awareness Month
9th Fetal Alcohol Syndrome Awareness Month
25th Ataxia Awareness Day

October
ADHD Awareness Month
Blindness Awareness Month
Down Syndrome Awareness Month
Dwarfism Awareness Month
Learning Disabilities Awareness Month
Spina Bifida Awareness Month
Rett Syndrome Awareness Month
1st World Cerebral Palsy Day
10th Bipolar Awareness Day
12th World Arthritis Awareness Day
22nd International Stuttering Awareness Day

November
Diabetes Awareness Month
Epilepsy Awareness Month
17th World Prematurity Awareness Day

December
2nd Special Education Day
3rd International Day of Persons with Disabilites

I have done my best to collate all of the information at my disposal. If I've omitted any day or month, please let me know!