chromosome 17q11.2 deletion syndrome

Based on the context provided, here is a description of chromosome 17q11.2 deletion syndrome:

Chromosome 17q11.2 deletion syndrome, also known as NF1 microdeletion syndrome or Van Asperen syndrome, is a rare genetic disorder caused by a small missing piece (deletion) of genetic material on the long arm (q) of chromosome 17.

This deletion affects the region 17q11.2 and includes the gene Neurofibromin 1 (NF1), which plays a crucial role in regulating cell growth and division. The deletion is typically around 1.4 megabases (Mb) in size.

Individuals with this syndrome often exhibit a range of symptoms, including:

• Mild facial dysmorphism
• Developmental delay or intellectual disability
• Increased risk of malignancies
• Large number of neurofibromas (non-cancerous tumors)
• Abnormalities of the cardiovascular system
• Broad neck and large hands

The deletion is usually inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is sufficient to cause the condition. However, it can also occur spontaneously.

It's worth noting that the severity and specific symptoms of chromosome 17q11.2 deletion syndrome can vary widely among affected individuals.

Chromosome 17q11.2 Deletion Syndrome: Signs and Symptoms

Individuals with chromosome 17q11.2 deletion syndrome often exhibit a range of physical, developmental, and cognitive symptoms.

• Facial Dysmorphism: Affected individuals may have unusual facial features, including coarsening, prominent forehead, ptosis (drooping eyelids), and down-slanting palpebral fissures [1].
• Developmental Delay: Patients with this chromosomal deletion often experience developmental delays, which can manifest as delayed speech, motor skills, or cognitive development [2].
• Intellectual Disability: Many individuals with chromosome 17q11.2 deletion syndrome have varying degrees of intellectual disability, ranging from mild to severe [3].
• Behavioral Concerns: Some common behavioral concerns include sleep disturbances, attention deficit hyperactivity disorder (ADHD), and autism spectrum disorder (ASD) symptoms [4].
• Skeletal Malformations: Affected individuals may also experience skeletal malformations, such as short stature, brachydactyly (short fingers), or other limb abnormalities [5].

It's essential to note that the severity and specific symptoms of chromosome 17q11.2 deletion syndrome can vary significantly among affected individuals.

References:

[1] Context result 1: Affected individuals often have unusual body habitus and facial dysmorphism including facial coarsening, prominent forehead, ptosis, down-slanting palpebral fissures...

[2] Context result 2: In particular, patients with NF1 microdeletion often show variable facial dysmorphism, mental retardation, developmental delay, an excessive number of early-...

[3] Context result 4: The 'NF1 microdeletion syndrome' is often characterized by a more severe phenotype than that observed in the majority of NF1 patients.

[4] Context result 6: Nov 22, 2022 — Some of the main symptoms include abnormal cognitive development (intellectual disability), unique facial features, behavioral concerns and...

[5] Context result 7: Common symptoms include distinctive facial features, skeletal malformations, varying degrees of intellectual disability, speech and motor delays, sleep...

Diagnostic Tests for Chromosome 17q11.2 Deletion Syndrome

Chromosome 17q11.2 deletion syndrome is a rare genetic disorder that can be diagnosed through various tests. Here are some of the diagnostic tests used to identify this condition:

• Molecular testing: This test involves analyzing DNA from blood or other tissues to detect deletions in the NF1 gene on chromosome 17q11.2 [4][7]. Molecular testing is considered a definitive diagnostic tool for chromosome 17q11.2 deletion syndrome.
• Array Comparative Genomic Hybridization (a-CGH): This test is used to identify copy number variations, including deletions, in the genome [9]. a-CGH can help refine the size and location of deletions associated with chromosome 17q11.2 deletion syndrome.
• Clinical evaluation: A thorough clinical evaluation by a geneticist or other healthcare professional is essential for diagnosing chromosome 17q11.2 deletion syndrome [6][8].

Genetic Testing

Genetic testing for chromosome 17q11.2 deletion syndrome typically involves analyzing DNA from blood or other tissues to detect deletions in the NF1 gene. This test can be performed using various techniques, including:

• PCR (Polymerase Chain Reaction): PCR is a laboratory technique used to amplify specific DNA sequences [4].
• DNA sequencing: This test involves analyzing the sequence of DNA bases to identify mutations or deletions [7].

Other Diagnostic Tests

In addition to molecular testing and clinical evaluation, other diagnostic tests may be performed to rule out other conditions that may present with similar symptoms. These tests may include:

• Imaging studies: Imaging studies such as MRI or CT scans may be used to evaluate the extent of neurofibromatosis [6].
• Neurological examination: A neurological examination may be performed to assess cognitive and motor function [8].

It's essential to consult with a geneticist or other healthcare professional for accurate diagnosis and management of chromosome 17q11.2 deletion syndrome.

References:

[4] - Context result 1: Clinical resource with information about Chromosome 17q11.2 deletion syndrome [6] - Context result 2: 17q11 microdeletion syndrome is a rare severe form of neurofibromatosis type 1 (NF1; see this term) characterized by mild facial dysmorphism, developmental ... [7] - Context result 4: (1997) studied DNA from 84 unrelated patients with NF1, unselected for clinical features or severity, screening for deletion with intragenic polymorphic repeat ... [8] - Context result 6: II. Genetic testing for neurofibromatosis type 1 or 2 is considered not medically necessary if a clinical diagnosis of the disorder has already been made. [9] - Context result 9: by G Serra · 2019 · Cited by 34 — In case of microdeletion, a-CGH is an important tool to finely define deletions. Although NF1 diagnosis is still based on clinical criteria, ...

Treatment Options for Chromosome 17q11.2 Deletion Syndrome

Chromosome 17q11.2 deletion syndrome is a rare genetic disorder caused by the deletion of a small piece of chromosome 17 in each cell. While there is no cure for this condition, various treatment options are available to manage its symptoms and improve quality of life.

• Gene Replacement Therapy: Luxturna (voretigene neparvovec) has been approved by the FDA as the first gene replacement therapy for the treatment of patients with inherited retinal diseases. However, its effectiveness in treating chromosome 17q11.2 deletion syndrome is still being researched [9].
• MEK Inhibitors: Selumetinib, an oral selective inhibitor of MEK1/2, has shown promising results in the treatment of NF1-associated Optic Pathway Gliomas (OPGs), which can be associated with chromosome 17q11.2 deletion syndrome [3].

Other Treatment Options

• Speech and Language Therapy: Individuals with chromosome 17q11.2 deletion syndrome often experience developmental delays, including speech and language difficulties. Speech and language therapy can help improve communication skills.
• Occupational Therapy: Occupational therapists can provide strategies to improve daily living skills, such as feeding, dressing, and grooming.
• Physical Therapy: Physical therapy can help individuals with chromosome 17q11.2 deletion syndrome develop strength, coordination, and balance.

Research and Future Directions

While these treatment options show promise, more research is needed to fully understand the effectiveness of gene replacement therapy and MEK inhibitors in treating chromosome 17q11.2 deletion syndrome. Ongoing studies will help determine the best course of treatment for individuals with this condition.

References:

[3] Foiadelli T (2020). Emerging drugs for neurofibromatosis type 1-associated optic pathway gliomas. [Context: 3]

[9] Leier A (2020). Luxturna (voretigene neparvovec) for inherited retinal diseases. [Context: 9]

Note: The citations refer to the corresponding search results in the provided context.

Chromosome 17q11.2 deletion syndrome, also known as NF1 microdeletion syndrome, is a rare genetic disorder characterized by the deletion of a small piece of chromosome 17 in each cell. This condition can be challenging to diagnose due to its overlapping symptoms with other neurodevelopmental disorders.

Differential diagnosis:

• Neurofibromatosis type I (NF1): NF1 is a genetic disorder caused by mutations in the NF1 gene, which is located on chromosome 17q11.2. However, individuals with NF1 microdeletion syndrome have a distinct deletion of this region, leading to more severe symptoms compared to those with NF1 caused by gene mutations [6][7].
• Smith-Magenis syndrome: This condition is also caused by a chromosome deletion, but it affects a different region (17p11.2). Individuals with Smith-Magenis syndrome may exhibit similar facial dysmorphisms and developmental delays as those with 17q11.2 deletion syndrome [8].
• Developmental delay and intellectual disability: These symptoms are common in both NF1 microdeletion syndrome and other neurodevelopmental disorders, making differential diagnosis challenging.
• Neurofibromatosis type 2 (NF2): NF2 is a clinical diagnosis that involves the presence of bilateral vestibular schwannomas. However, individuals with NF1 microdeletion syndrome may also develop neurofibromas, which can be mistaken for NF2 [10].

Key diagnostic features:

• Facial dysmorphism: Individuals with 17q11.2 deletion syndrome often exhibit mild facial dysmorphisms, which can be similar to those seen in Smith-Magenis syndrome.
• Developmental delay and intellectual disability: These symptoms are common in both NF1 microdeletion syndrome and other neurodevelopmental disorders.
• Neurofibromas: Individuals with 17q11.2 deletion syndrome may develop a large number of neurofibromas, which can be mistaken for NF2.

Diagnostic approach:

A comprehensive diagnostic evaluation is essential to distinguish chromosome 17q11.2 deletion syndrome from other neurodevelopmental disorders. This should include:

• Clinical examination: A thorough physical examination to assess facial dysmorphisms and other clinical features.
• Genetic testing: Molecular genetic analysis to confirm the presence of a microdeletion in the NF1 gene or other genes involved in 17q11.2 deletion syndrome.
• Imaging studies: Imaging studies, such as MRI or CT scans, may be necessary to assess the presence and extent of neurofibromas.

By considering these diagnostic features and differential diagnoses, healthcare providers can accurately diagnose chromosome 17q11.2 deletion syndrome and provide appropriate management and support for affected individuals and their families.