What is the Difference Between Fragile X and Down Syndrome

The key difference between Fragile X and Down syndrome is that Fragile X syndrome is due to the mutation of a gene called FMR1 in the X chromosome, while Down syndrome is due to the presence of an extra copy of the 21 chromosome.

Intellectual disability triggers impaired cognitive development and daily lifestyle functions. Fragile X and Down syndrome are the two most prevalent genetic causes of intellectual disability in people. Both these genetic conditions may have similar symptoms, such as a lack of expressive language abilities, increased risk for autism spectrum disorder, seizure disorders, and other mental health disorders.

CONTENTS

1. Overview and Key Difference
2. What is Fragile X Syndrome
3. What is Down Syndrome
4. Similarities – Fragile X and Down Syndrome
5. Fragile X vs. Down Syndrome in Tabular Form
6. Summary – Fragile X vs. Down Syndrome

What is Fragile X Syndrome?

Fragile X syndrome is a prevalent cause of inherited intellectual disability such as autism. Fragile X syndrome is also known as Martin-Bell syndrome. It is a genetic disorder due to the mutation of a gene called FMR1 in the X chromosome. It is estimated about 1 in 8,000 to 11,000 females and 1 in 4,000 to 7,000 males have fragile X syndrome worldwide. Moreover, the symptoms of this condition may include developmental delays such as speech, language, and communication difficulties, intellectual disability and learning problems, anxiety or depression, autism-like behaviors like hand flapping, repeating words and sentences, and difficulty in social interactions with people, behavioral problems, attention deficit hyperactivity disorder, poor eye contact, and difficulty in processing sensory information.

Fragile X syndrome can be diagnosed through family history, physical examination, blood test, and DNA testing. Furthermore, there is no cure for fragile X chromosome syndrome. However, therapies to learn to talk, walk, and interact with others and medicines such as selective serotonin reuptake inhibitors (SSRIs) to help control some issues, such as behavior problems, may be helpful in fragile X syndrome.

What is Down Syndrome?

Down syndrome is an inherited genetic disorder caused by an extra full or partial copy of chromosome 21. This extra genetic material triggers the developmental changes and physical features of Down syndrome. The data suggest each year, about 6,000 babies are born with Down syndrome worldwide, which is about 1 in every 700 babies born. Moreover, the signs and symptoms of Down syndrome may include a flattened face, smaller head and neck, protruding tongue, palpebral fissures, the unusual shape of ears, poor muscle tone, broad, short hands with a single crease in the palm, short fingers, high flexibility, tiny white spots on the iris of the eye, short height and intellectual disabilities.

Down syndrome can be diagnosed through family history, physical examination, blood test, nuchal translucency test (ultrasound, chorionic villus sampling (CVS) and amniocentesis, and genetic testing. Furthermore, there is no single, standard treatment regime for Down syndrome. However, the symptoms can be managed by physical therapy, occupational therapy, speech therapy, participating in special education programs in school or held in other places, managing any underlying medical conditions, and wearing glasses for vision problems or assisted hearing devices for hearing loss problems.

What are the Similarities Between Fragile X and Down Syndrome?

• Fragile X and Down syndrome are the two most prevalent genetic causes of intellectual disability in people.
• Both syndromes are rare.
• They may have similar symptoms, such as a lack of expressive language abilities, increased risk for autism spectrum disorder, seizure disorders, and other mental health disorders (anxiety, depression, etc.).
• Both syndromes can be diagnosed through family history, physical examination, blood test, and genetic testing.
• There is no proper cure for both syndromes.

What is the Difference Between Fragile X and Down Syndrome?

Fragile X syndrome is due to the mutation of a gene called FMR1 in the X chromosome, while Down syndrome is due to the presence of an extra copy of the 21 chromosome. Thus, this is the key difference between Fragile X and Down syndrome. Furthermore, fragile X syndrome affects about 1 in 8,000 to 11,000 females and 1 in 4,000 to 7,000 males worldwide. On the other hand, Down syndrome affects 1 in every 700 babies born worldwide.

The infographic below presents the differences between Fragile X and Down syndrome in tabular form for side-by-side comparison.

Summary – Fragile X vs. Down Syndrome

Intellectual disability results in limitations in cognitive function and skills such as conceptual and practical skills like language, social, and self-care skills. Fragile X and Down syndrome are the two most prevalent genetic causes of intellectual disability in people. Both these syndromes may have similar symptoms like deficit expressive language abilities, increased risk for autism spectrum disorder, seizure disorders, and other mental health disorders. However, fragile X syndrome is an inherited genetic disorder caused by changes in a gene called fragile X messenger ribonucleoprotein 1 (FMR1) in the X chromosome. Down syndrome is an inherited genetic disorder caused by an extra full or partial copy of chromosome 21. So, this summarizes the difference between Fragile X and Down syndrome

Reference:

1. “Fragile X Syndrome: Diagnosis, Symptoms & Treatment.” Cleveland Clinic.
2. “Down Syndrome.” Mayo Clinic, 8 Mar. 2018.

Image Courtesy:

1. “Fmr1” (Public Domain) via Commons Wikimedia
2. “Down syndrome lg” By Centers for Disease Control and Prevention,  National Center on Birth Defects and Developmental Disabilities – (Public Domain) via Commons Wikimedia