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Differential Diagnosis

The characteristics of autism are present in a number of other conditions. Professionals must use caution and conduct thorough evaluations as to rule out the possibility of these related syndromes/disorders. The following is a list of conditions that exhibit symptoms similar to those of autism:

Congenital Rubella syndrome (CRS): can occur in the developing fetus of a pregnant woman who has contracted the rubella virus during her first trimester. This can result in the child being born dead, blind, with cardiac problems, developmental delays, and other medical conditions.

Cornelia de Lange syndrome (CdLS): Cornelia de Lange syndrome is a genetic disorder the can cause a range of physical, cognitive, and medical challenges and, unlike ASD, affects both genders equally.

Fragile X syndrome (FXS): Fragile X syndrome (FXS) is a genetic condition that causes intellectual disability, behavioral and learning challenges, and various physical characteristics. Males are more frequently affected than females, and generally with greater severity.

Klüver-Bucy syndrome: Klüver-Bucy syndrome is a rare behavioral impairment that is associated with damage to both of the anterior lobes of the brain. Symptoms include hypersexuality, visual agnosia (inability to recognize objects), loss of normal fear and anger responses, memory loss, distractibility, seizures, and dementia.

Landau-Kleffner syndrome (LKS): Landau-Kleffner syndrome (LKS) is an acquired epileptic disorder in children that can cause a sudden or gradual loss of language skills in typically developing children. 70-75% of children experience overt clinical seizures, but the identifying symptom is the presence of subclinical seizure activity that is only detectable through the use of electroencephalograms (EEGS).

Lesch-Nyhan disease (LND): Lesch-Nyhan disease (LND) is a rare X-linked recessive disorder that involves a virtual complete absence of activity of the enzyme HPRT, which results in the extreme overproduction of uric acid and related symptoms of gout and renal dysfunction. Additionally, neurological abnormalities include spasticity, choreoasthetosis, dysarthria, and a unique compulsion towards self-injurious behavior, the abuse of others, and to lie and curse.

Prader-Willi syndrome (PWS): Prader-Willi syndrome is the most common known genetic cause of life-threatening obesity in children. PWS can cause low muscle tone, short stature (unless treated by growth hormone), incomplete sexual development, and a chronic feeling of hunger.

Rett syndrome: Rett syndrome is a developmental disorder that is first recognized in infancy and predominantly occurs in girls, but is also rarely seen in boys. Rett syndrome is often misdiagnosed as ASD, cerebral palsy, or another developmental delay. However, unlike autism, Rett syndrome can be confirmed by a simple blood test.

Tourette syndrome (TS): Tourette syndrome is a neurological disorder which becomes evident in early childhood. TS is defined by multiple motor and vocal tics that last for more than one year.

Tuberous Sclerosis (TSC): Tuberous sclerosis complex (TSC) is a genetic disorder that causes tumors to form in many different organs, mainly in the brain, eyes, heart, kidney, skin, and lungs. An estimated 50,000 individuals have TSC in the United States, with approximately 1 million cases worldwide.

Untreated Phenylketonuria (PKU): Phenylketonuria (PKU) is a genetic inborn error of metabolism that is detectable in the first days of life through appropriate blood tests (newborn screening). If left untreated, the disorder can create neurological abnormalities, seizures, and other medical problems.

Williams syndrome: Williams syndrome is a genetic condition that is present at birth and is characterized by medical problems, including cardiovascular disease, developmental delays, and learning disabilities. These symptoms co-exist with outstanding verbal abilities, highly social personalities, and an affinity for music.

Down syndrome: Down syndrome occurs when an individual has a full or partial extra copy of chromosome 21. Physical characteristics of Down syndrome include low muscle tone, small stature, an upward slant to the eyes, and a single deep crease across of the palm. Like ASD, every individual is unique and may display some of these features of none at all.

1. “Differential Diagnosis.” Autism Society. Accessed September 5, 2012. http://www.autism-so...-diagnosis.html.