JACOBSEN SYNDROME 

 

Jacobsen Syndrome, also known as 11q deletion disorder, is a rare congenital disorder resulting from deletion of a terminal region of chromosome 11 that includes band 11q24.1. It can cause intellectual disabilities, a distinctive facial appearance, and a variety of physical problems including heart defects and a bleeding disorder. The syndrome was first identified by Danish physician Petra Jacobsen.

 

Overview of Jacobsen Syndrome

Jacobsen syndrome is a major inborn condition. It causes mental retardation and multiple birth defects.

The syndrome occurs when genetic material is missing from chromosome 11. This can affect over 340 genes critical to the normal bodily development.

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Jacobsen syndrome is very rare. It affects only 1 in 100,000 newborns (LHNCBC).

About twice as many females are born with the syndrome as males (INSERM). In most cases, the condition isn’t inherited. It is caused by a mistake during reproductive cell division when a baby is being formed in the womb.

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Common Characteristics

Jacobsen syndrome causes a wide range of symptoms and physical defects.

 

Delayed Development

Many infants born with Jacobsen syndrome have central nervous system (CNS) defects.

These can affect how the brain and spinal cord function. The result is impaired intelligence, learning, speech, and motor skills (NICHD).

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Affected children can have problems speaking, walking, standing, and sitting normally. Later, behavioral problems can occur. The most common issues are:

• compulsive behavior

• short attention span

• easily distracted

 

Children with Jacobsen syndrome are often diagnosed with attention deficit hyperactivity disorder (ADHD).

 

Congenital Defects and Common Illnesses

Short build and skull abnormalities also occur. These include a large-sized head, calledmacrocephaly, or pointed forehead, called trigonocephaly.

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Other common facial deformities include:

• wide-set eyes (hypertelorism)

• droopy eyelids (ptosis)

• skin covering the inner corners of the eyes (epicanthal folds)

• broad nasal bridge

• V-shaped mouth

• small lower jaw

• small low-set ears, rotated backwards

 

Over 90 percent of affected newborns have a bleeding disorder called Paris-Trousseau syndrome (LHNCBC). This prevents blood from clotting, and causes excessive bleeding and easy bruising. 

Other common issues include:

• heart defects and congenital heart disease

• kidney defects

• gastrointestinal abnormalities

• eating difficulties and failure to thrive

• otitis media, frequent ear infections, sinusitis, and recurrent respiratory infections

• genitalia abnormalities

 

Newborns with Jacobsen syndrome may have trouble eating. Often, they need to be fed through a tube. These babies have problems gaining weight and growing normally.

Eyesight, hearing, immune system, and hormonal anomalies can also affect children with Jacobsen syndrome.

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How Is it Diagnosed?

Diagnosis usually occurs at birth or in early childhood. Facial dysmorphism and blood platelet dysfunction are distinctive signs of the condition (INSERM).

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Doctors can conduct blood tests, auditory tests, and endocrine and immunological assessments. A chromosome test called cytogenetic analysis confirms diagnosis.

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Prenatal diagnosis is also possible with cytogenetic analysis. This involves taking a sample of amniotic fluid or chorionic villus. These samples are taken from the placenta of a pregnant mother. However, there is some risk of miscarriage (NIH).

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How Is it Treated?

There is no cure for Jacobsen syndrome. But treatments can help with some symptoms.

Care for newborns usually requires specialists, including:

• pediatricians

• pediatric cardiologists

• neurologists

• ophthalmologists

• orthopedic specialists

 

Surgeries may be needed to repair malformations, including gastrointestinal corrections. Major cardiac defects can require heart surgery in infants.

 

Because there is a bigger risk of bacterial infection of the heart lining and valves with heart surgery, antibiotics may be needed with heart surgery (ORDR).

 

Blood or platelet problems should be monitored frequently. Transfusions may be necessary with any surgery. Respiratory, sinus, and ear infections should be aggressively treated early. Eye defects may be improved with glasses, contact lenses, or eye surgery. Abnormalities injoints, tendons, muscles, and bones may be treated by orthopedic techniques. These can potentially be in combination with surgery. Physical therapy may help improve coordination and mobility.  Delayed development treatments include physical, speech, and occupational therapy. Specialeducation classes and psychological counseling can help with learning and behavior management.  Early interventions are important to help affected children reach their full potential.

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What Is the Outlook for Children With Jacobsen Syndrome?

About 20 percent of infants with Jacobsen syndrome die by age 2. Early death is most commonly due to heart problems, and less commonly due to bleeding (INSERM).

 

The life expectancy of people with Jacobsen syndrome isn’t known, but some individuals have lived into adulthood.