Recent Advances in the Pathogenesis of Syndromic Autisms

Table 2

Genetic syndromes associated with autism.

Syndrome	Gene(s) associated with the syndrome	Proportion of patients with an ASD that have the syndrome	Proportion of patients with the syndrome that have an ASD	Clinical signs	Refs
Fragile-X syndrome	FMR1	2–5%	20–40%	Mental retardation, long face with prominent ears, macroorchidism, social anxiety, sensory hypersensitivity, stereotypies, poor motor coordination, delayed speech development.	[56, 57]
Tuberous sclerosis	TSC1, TSC2	3–4%	43–86%	Epilepsy, mental retardation, specific learning disabilities, ADHD disorder, autistic spectrum disorders.	[58, 59]
15q duplication Angelman/Prader Will syndrome	UBE3A GABAr cluster	1–2%	>40%	Ataxia, language delay, epilepsy, mental retardation, repetitive movements, obsessive-compulsive symptoms.	[60]
16p11 deletion	PCKB1	1%	High	Developmental delay, distinct facial appearance, autism.	[46, 61]
22q deletion	SHANK3	1%	High	Speech and language disability, social impairment.	[62, 63]
2q37 deletion	KIF1A, GBX2	Unknown	50%	Developmental delay, mental retardation, hypotonia, hyperactivity, autistic traits, dysmorphic features (cleft palate, temporal bone abnormalities, hypoplastic lungs).	[64]
Joubert syndrome	AHI1	Unknown	40%	Partial/complete agenesis of the cerebellar vermis, ataxia, abnormalities of ocular movements, cognitive, and behavioral dysfunction.	[65]
Timothy syndrome	CACNA1C	Unknown	60–70%	Cardiac arrhythmia, long QT syndrome, mental retardation, and ASD.	[66]
Cortical dysplasia-focal epilepsy syndrome	CNTNAP2	Rare	70%	Seizures and language regression.	[67, 68]