Autism is a neurological and developmental disorder that affects 
communication and behaviour. It is known to cause a triad of impairment in imagination, language and social interaction. According to the Centre for Disease Control and Prevention (CDC~2014 census), 1 in 69 individuals are affected by Autism.
Cause
The exact cause of Autism is not known. Majority are unknown or due to acquired brain injury. Genetic factors play a major part in Autism (15-40% will have an identifiable genetic cause). It may be caused by several genes acting together with environmental factors, some are secondary –syndromic.
Features
Presentation of symptoms differs between children; some are perceived by parents as different during infancy, others present with delayed speech development and a proportion regress and lose skills after the first year of life. In infancy-absence of social smile by 3 months, more interested in objects than faces, no response to name, inability to follow pointing hand and struggling to imitate actions No
vocalization by 6 months, babbling by 1year
Commonly seen signs are:
- Restricted and repetitive behaviour
- Peculiar mannerisms
- Unusual attachments to objects
- Stereotypies include hand flapping, finger movements, rocking or twirling
- Hyperactivity, delayed motor skills with poor coordination
- Social skills deficits- prefer being alone, do not make eye contact
- Learning difficulty, around 75% of children will have an intellectual disability
Diagnosis
Diagnosing Autism can be difficult, as there is no direct test. It takes comprehensive holistic evaluation of an individual to place them in the spectrum. This involves developmental screening and comprehensive diagnostic evaluation.
Benefits of early diagnosis Intervention provided before age three years has a much greater impact than intervention provided after age five. It will help in:
- The child’s overall language development
- Improvement in cognitive functions
- Gains in initiation of spontaneous communication
- Understanding the genetic diagnosis
- Helps identify other underlying health conditions.
- Helps provide understanding for recurrence risk and planning for a future pregnancy.
Genetic Associations
Current Autism Databases consist of 1036 reported genes and 2274 reported Copy number variations (CNVs). Some of the common genetic conditions and CNVs associated are:
- Fragile X syndrome
- Rett syndrome
- Angelman syndrome
- Tuberous sclerosis
- Phenylketonuria
- Common CNVs- 1q21.1dup, 7q11.23 dup, 15q11-q13 dup, 16p11.2 del/dup and
22q11.2 del.
Recurrence risk
- When genetic etiology is unknown, the risk of recurrence is 3-14%.