Summary about Disease
Chromosome 18q deletion syndrome is a genetic disorder that occurs when a portion of the long arm (q) of chromosome 18 is missing. The size of the deletion can vary, leading to a wide range of symptoms and severity. This syndrome is characterized by intellectual disability, developmental delays, distinctive facial features, limb abnormalities, and internal organ problems. It's a rare condition and not inherited in most cases, arising spontaneously during the formation of egg or sperm cells, or early embryonic development.
Symptoms
The symptoms of Chromosome 18q deletion syndrome can vary greatly depending on the size and location of the deleted segment. Common symptoms include:
Intellectual disability: Mild to moderate intellectual disability is often present.
Developmental delays: Delays in reaching developmental milestones such as walking, talking, and toilet training are common.
Facial features: Distinctive facial features may include a deep-set eyes, a small mouth, a prominent nose, and low-set ears.
Limb abnormalities: These can include clubfoot, overlapping toes, and long, tapering fingers.
Growth deficiency: Some individuals may experience slower growth than their peers.
Hearing loss: Conductive or sensorineural hearing loss is common.
Vision problems: Strabismus (crossed eyes), cataracts, or other visual impairments can occur.
Heart defects: Congenital heart defects may be present.
Skeletal abnormalities: Scoliosis or other skeletal problems may develop.
Hypotonia: Low muscle tone can affect feeding and motor skills.
Psychiatric/behavioral problems: Autism spectrum disorder, anxiety, aggression, or hyperactivity.
Causes
Chromosome 18q deletion syndrome is caused by a deletion (missing piece) of genetic material on the long arm (q) of chromosome 18. In most cases, the deletion occurs randomly during the formation of egg or sperm cells (de novo mutation) or during early embryonic development. Rarely, the deletion is inherited from a parent who carries a balanced translocation involving chromosome 18. In a balanced translocation, a piece of a chromosome has broken off and attached to another chromosome, with no overall gain or loss of genetic material. A parent with a balanced translocation is usually unaffected, but they have an increased risk of having a child with a chromosome deletion or duplication.
Medicine Used
There is no specific medication to cure or reverse chromosome 18q deletion syndrome. Treatment focuses on managing the individual's symptoms and providing supportive care. Medications that might be used include:
Medications for specific medical conditions: For example, heart medications for congenital heart defects, anti-seizure medications for seizures, or medications for behavioral problems.
Pain relievers: For pain associated with skeletal or other physical problems.
Hormone therapy: In cases of growth hormone deficiency.
Is Communicable
Chromosome 18q deletion syndrome is not communicable. It is a genetic disorder, not an infectious disease, and cannot be spread from person to person.
Precautions
Since Chromosome 18q deletion syndrome is not communicable, standard precautions related to infectious disease control are not applicable. Precautions are focused on managing the individual's specific health issues and preventing complications:
Regular medical checkups: Monitoring for potential complications such as heart problems, hearing loss, vision problems, or skeletal abnormalities is crucial.
Developmental therapies: Early intervention programs and therapies can help individuals reach their full potential.
Special education: Providing appropriate educational support is important for individuals with intellectual disability.
Genetic counseling: For families who are planning to have more children.
Hearing protection: To prevent further hearing loss, if hearing loss is present.
How long does an outbreak last?
This disorder is not an outbreak.
How is it diagnosed?
Diagnosis of Chromosome 18q deletion syndrome typically involves:
Clinical evaluation: A healthcare professional will assess the individual's symptoms and physical characteristics.
Chromosomal microarray analysis (CMA): This genetic test can detect deletions and duplications of chromosomal material, including deletions on chromosome 18q.
Karyotype: A karyotype is a test that examines the chromosomes under a microscope. While CMA is more sensitive, a karyotype can sometimes detect larger deletions.
Fluorescent in situ hybridization (FISH): FISH is a cytogenetic technique that can be used to confirm a suspected deletion or to identify the specific region of chromosome 18 that is deleted.
Prenatal testing: Chromosomal abnormalities can be detected during pregnancy through amniocentesis or chorionic villus sampling (CVS), followed by CMA or karyotype analysis.
Timeline of Symptoms
The timeline of symptoms can vary greatly. Some symptoms may be present at birth, while others develop later in childhood:
Prenatal/Newborn: Some physical characteristics, such as facial features or limb abnormalities, may be noticeable at birth. Heart defects may be diagnosed shortly after birth. Hypotonia (low muscle tone) can affect feeding.
Infancy: Developmental delays become apparent. Hearing loss may be detected.
Childhood: Intellectual disability is diagnosed. Speech and language delays are evident. Behavioral problems may emerge. Skeletal abnormalities may develop. Vision problems may become apparent.
Adolescence/Adulthood: Individuals continue to require ongoing medical and developmental support. Scoliosis may progress. Psychiatric issues may persist.
Important Considerations
Variability: The severity of symptoms varies greatly among individuals with chromosome 18q deletion syndrome.
Early intervention: Early diagnosis and intervention are crucial for maximizing developmental potential.
Multidisciplinary care: Individuals with this syndrome require care from a team of specialists, including geneticists, pediatricians, cardiologists, audiologists, ophthalmologists, neurologists, and therapists.
Support groups: Connecting with other families affected by chromosome 18q deletion syndrome can provide valuable support and information.
Life expectancy: While there can be serious health problems, with appropriate medical care and management, many individuals with chromosome 18q deletion syndrome can live into adulthood. Life expectancy depends on the severity of associated medical problems.