Jacobsen Syndrome

What is Jacobsen Syndrome?

Jacobsen syndrome, also known as 11q terminal deletion disorder, is a rare congenital condition caused by the loss (deletion) of genetic material from chromosome 11 [1]. This deletion most commonly occurs at the end (terminus) of the long (q) arm of chromosome 11 [2].

Characteristics and Symptoms

The condition is characterized by developmental delays, including delayed motor and speech development [6], as well as distinctive facial features such as a broad nasal bridge, short nose, V-shaped mouth, and small, low-set and posteriorly rotated ears [12]. Other symptoms may include Paris-Trousseau syndrome (a bleeding disorder), craniosynostosis, eye abnormalities, and cognitive impairment [3].

Prevalence and Diagnosis

Jacobsen syndrome is a rare condition, occurring in about 1 in 100,000 births [9][11], with a female to male ratio of 2:1 [13]. The deletion may range from 5 million to 16 million deleted DNA base pairs, affecting the severity of symptoms [9].

References

[1] Context result 10 [2] Context result 4 [3] Context result 3 [6] Context result 6 [9] Context result 9 [11] Context result 11 [12] Context result 12 [13] Context result 13

Jacobsen Syndrome: A Rare Chromosomal Disorder

Jacobsen syndrome, also known as 11q terminal deletion disorder, is a rare chromosomal disorder caused by the loss (deletion) of genetic material from chromosome 11. The signs and symptoms of Jacobsen syndrome vary considerably among affected individuals.

Common Signs and Symptoms:

• Delayed Development: Most affected people experience delayed development of motor skills and speech.
• Cognitive Impairment: Cognitive impairment is a common feature, leading to learning difficulties.
• Behavioral Features: Behavioral features have been reported, including compulsive behavior, short attention span, and distractibility.
• Physical Characteristics:
  • Abnormal facial features (e.g., ptosis, coloboma, downslanting palpebral fissures)
  • Craniofacial dysmorphism (skull deformities, hypertelorism)
  • Short stature
  • Wide neck
  • Small, low-set and posteriorly rotated ears
• Medical Conditions:
  • Congenital heart disease
  • Eye abnormalities
  • Pulmonary or aortic stenosis

Variability in Symptoms:

The severity of symptoms depends on the size of genetic material lost from chromosome 11. Some individuals may experience mild symptoms, while others may have more severe physical and cognitive impairments.

References:

• [1] Jacobsen syndrome is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when ...
• [2] The severity of symptoms depends on the size of genetic material lost from chromosome 11.
• [3] Signs and symptoms vary among affected people but often include Paris-Trousseau syndrome (a bleeding disorder); distinctive facial features; delayed development of motor skills and speech; and cognitive impairment.
• [4] Jacobsen syndrome is a rare chromosomal disorder resulting from deletion of genes from chromosome 11 that includes band 11q24.1.

Note: The above information is based on the search results provided in the context, which include various sources citing the signs and symptoms of Jacobsen syndrome.

Diagnostic Tests for Jacobsen Syndrome

Jacobsen syndrome, also known as 11q deletion syndrome, is a rare genetic disorder caused by the deletion of several genes on chromosome 11. Diagnosing this condition can be challenging, but various diagnostic tests can help confirm the presence of Jacobsen syndrome.

• Genetic testing: Fluorescence in situ hybridization (FISH) or microarray analysis can detect the deletion on chromosome 22 at [1]. However, for Jacobsen syndrome, genetic testing typically involves analyzing the genes on chromosome 11.
• Array comparative genomic hybridization (aCGH): This test is used to identify deletions or duplications of genetic material. aCGH can confirm the presence of a deletion on chromosome 11, which is characteristic of Jacobsen syndrome [2].
• FISH: FISH testing can also be used to detect the deletion on chromosome 11. This test involves analyzing the chromosomes for specific genetic markers [1].
• Clinical findings and laboratory tests: Diagnosis is typically made by healthcare professionals based on a person's medical history, symptoms, physical exam, and laboratory test results [8]. Auditory tests, blood tests, endocrine and immunological assessment, and follow-up should be offered to all patients [4].

Non-invasive prenatal testing/screening (NIPT/S): NIPT/S may be able to detect an increased chance of a fetus carrying an 11q deletion, which is associated with Jacobsen syndrome. However, this test is not definitive and requires further confirmation [5].

It's essential to note that diagnosis can take time, and a combination of these tests may be necessary to confirm the presence of Jacobsen syndrome.

References: [1] - Context result 1 [2] - Context result 8 [4] - Context result 7 [5] - Context result 6 [8] - Context result 9

Treatment Options for Jacobsen Syndrome

Jacobsen syndrome, a rare congenital condition caused by the deletion of several genes in chromosome 11, requires a multi-disciplinary approach to management and treatment. While there is no cure for Jacobsen syndrome, various treatments can help alleviate symptoms and improve quality of life.

• Growth Hormone Replacement Therapy: Controversial due to potential genetic predisposition to malignancies, growth hormone replacement therapy may be considered on a case-by-case basis [5].
• Medications for Complications: Medications may be used to manage complications such as heart defects and platelet issues in newborns diagnosed with Jacobsen syndrome [6].
• Immunodeficiency Treatment: Patients with Jacobsen syndrome can be predisposed to cutaneous viral infections that are difficult to treat. Topical 1% cidofovir has been reported as a successful treatment for these infections [4].
• Anti-anxiety Drug Clonazepam: Research suggests that the anti-anxiety drug clonazepam may reduce autistic features in Jacobsen syndrome mice, potentially offering a new treatment approach for social and behavioral issues associated with the condition [3][12][14].

Important Considerations

It is essential to consult with a healthcare professional for medical advice and treatment. A multi-disciplinary team, including pediatricians, cardiologists, neurologists, hematologists, allergy/immunologists, and other specialists, may be required to manage the complex needs of individuals with Jacobsen syndrome [7].

References

[4] Context result 4 [3] Context result 3 [5] Context result 5 [6] Context result 6 [7] Context result 7

Differential Diagnoses for Jacobsen Syndrome

Jacobsen syndrome, also known as MCA/MR contiguous gene syndrome, is a rare chromosomal disorder caused by partial deletion of the long arm of chromosome 11. When diagnosing Jacobsen syndrome, it's essential to consider other conditions that may present similar symptoms. Here are some differential diagnoses for Jacobsen syndrome:

• Turner Syndrome: This genetic condition affects females and is characterized by short stature, delayed puberty, and infertility. While Turner syndrome shares some similarities with Jacobsen syndrome, such as developmental delays and physical abnormalities, the two conditions have distinct differences.
• Noonan Syndrome: This rare genetic disorder affects both males and females and is characterized by heart defects, short stature, and distinctive facial features. Like Turner syndrome, Noonan syndrome can present similar symptoms to Jacobsen syndrome, but it has a different underlying cause.
• Acquired Thrombocytopenia due to Sepsis: This condition occurs when the body's platelet count drops due to infection or sepsis. While it may share some similarities with Jacobsen syndrome in terms of physical abnormalities and developmental delays, it is not a genetic disorder like Jacobsen syndrome.
• Triploidy: This rare chromosomal disorder occurs when there are three sets of chromosomes instead of the usual two. Triploidy can present similar symptoms to Jacobsen syndrome, such as developmental delays and physical abnormalities, but it has a distinct underlying cause.
• Trisomy 18 (Edwards Syndrome): This genetic condition is characterized by severe developmental delays, heart defects, and physical abnormalities. While trisomy 18 shares some similarities with Jacobsen syndrome, the two conditions have distinct differences in terms of their underlying causes and symptoms.

References

• [1] Turner syndrome can be ruled out based on the presence of chromosomal deletion in Jacobsen syndrome.
• [2] Noonan syndrome is a distinct genetic disorder that presents similar symptoms to Jacobsen syndrome but has a different underlying cause.
• [3] Acquired thrombocytopenia due to sepsis is not a genetic disorder and can be ruled out based on the presence of chromosomal deletion in Jacobsen syndrome.
• [4] Triploidy is a rare chromosomal disorder that presents similar symptoms to Jacobsen syndrome but has a distinct underlying cause.
• [5] Trisomy 18 (Edwards Syndrome) is a severe genetic condition that shares some similarities with Jacobsen syndrome, but the two conditions have distinct differences in terms of their underlying causes and symptoms.