chromosome 1q21.1 deletion syndrome

Chromosome 1q21.1 Deletion Syndrome: A Rare Genetic Condition

Chromosome 1q21.1 deletion syndrome is a rare genetic condition characterized by the deletion of a small piece of chromosome 1, specifically at the q21.1 region. This deletion can lead to various physical and developmental abnormalities.

Key Features:

• Microcephaly: Individuals with this syndrome often have an unusually small head size [1].
• Developmental Delay: Global developmental delay or mild intellectual disability is a common feature of this condition [6][8].
• Low Muscle Tone: Affected individuals may exhibit low muscle tone, which can lead to poor growth and development [7][8].
• Behavioral Issues: Behavioral issues such as aggression and attention problems are also associated with this syndrome [7][8].

Clinical Phenotype:

The clinical phenotype of chromosome 1q21.1 deletion syndrome is extremely variable, but the most common non-constant clinical findings include microcephaly, developmental delay or mild intellectual disability, and small head size [6]. The severity and presentation of symptoms can vary widely among affected individuals.

Causes:

This disease is caused by changes to the number or structure of a person's chromosomes, specifically the deletion of a small piece of chromosome 1 at the q21.1 region [3].

References:

[1] Oct 1, 2012 - A microdeletion includes an unusually small head (microcephaly), short stature, and eye problems such as clouding of the lenses (cataracts).

[3] A 1q21.1 microdeletion is a very rare genetic condition in which a tiny piece is missing from one of the body's 46 chromosomes.

[6] The clinical phenotype is extremely variable; the most common but non-constant clinical findings include microcephaly, developmental delay or mild intellectual disability.

[7] Symptoms: Low muscle tone, global developmental delay, intellectual disability, small head size, poor growth, behavioral issues like aggression, attention problems.

[8] 1q21.1 Deletion - Low muscle tone, global developmental delay, intellectual disability, small head size, poor growth, behavioral issues like aggression.

Common Signs and Symptoms

Chromosome 1q21.1 deletion syndrome can manifest in various ways, and the severity of symptoms may vary from person to person. Some common signs and symptoms include:

• Developmental Delay: Approximately 75% of individuals with a 1q21.1 microdeletion exhibit delayed development, particularly in motor skills such as sitting, walking, or talking [7].
• Microcephaly: An unusually small head size is a common feature among individuals with this syndrome [2, 12].
• Short Stature: Short stature is another common symptom, which may be accompanied by poor growth and developmental delay [8].
• Eye Problems: Eye problems such as cataracts, clouding of the lenses, or other abnormalities are also associated with chromosome 1q21.1 deletion syndrome [2, 12].
• Intellectual Disability: Intellectual disability is a possible symptom, ranging from mild to severe, depending on the size and location of the deletion [13, 15].
• Behavioral Issues: Behavioral issues such as aggression, anxiety, or other psychiatric disorders may also be present in individuals with this syndrome [9].

Other Possible Symptoms

In addition to these common symptoms, chromosome 1q21.1 deletion syndrome can also lead to a range of other clinical manifestations, including:

• Developmental Delays: Delays in speech, language, or cognitive development
• Physical Abnormalities: Distinctive facial features, heart defects, skeletal abnormalities, or urinary system issues
• Seizures: Seizure disorders may be present in some individuals with this syndrome

Variability of Symptoms

It's essential to note that the symptoms of chromosome 1q21.1 deletion syndrome can vary widely from person to person, and some individuals may not exhibit any noticeable symptoms at all [10]. The degree of signs and symptoms is often related to the amount of chromosome material deleted and the number of genes affected.

References:

[2] Oct 1, 2012 — Other common signs and symptoms of 1q21.1 microdeletions include an unusually small head (microcephaly), short stature, and eye problems such ... [7] Signs and symptoms. edit. Approximately 75% of all children with a 1q21.1 microdeletion exhibit delayed development, notably in motor skills such as sitting ... [8] 1q21.1 Deletion · Low muscle tone · Global developmental delay · Intellectual disability · Small head size · Poor growth · Behavioral issues like aggression ... [9] by YH Kim · 2018 · Cited by 1 — 1 microdeletion exhibit neurological-psychiatric problems, microcephaly, epilepsy, facial dysmorphism, cataract, and thrombocytopenia absent ... [10] Some individuals diagnosed with microdeletion show no symptoms of the syndrome at all, the reasons for this are still being researched. [12] Other common signs and symptoms of 1q21.1 microdeletions include an unusually small head (microcephaly), short stature, and eye problems such as clouding of the lenses (cataracts). [13] This deletion can result in a variety of different clinical phenotypes or symptoms, including developmental delay, intellectual disability, psychiatric disorders, and physical abnormalities. [15] 1q21.1 deletion syndrome is a rare genetic disorder that occurs when a small piece of chromosome 1 is missing. This deletion can lead to a range of developmental and physical challenges, depending on the size and location of the deletion. ... The symptoms of 1q21.1 deletion syndrome can vary widely from person to person, but some common signs ...

Diagnostic Tests for Chromosome 1q21.1 Deletion Syndrome

Chromosome 1q21.1 deletion syndrome is a genetic disorder caused by the deletion of a small piece of chromosome 1. The diagnostic tests for this condition are crucial in confirming the presence of the microdeletion.

• Molecular Genetics Tests: These tests can detect the recurrent distal heterozygous deletion between BP3 and BP4, which is characteristic of chromosome 1q21.1 deletion syndrome [2].
• Chromosome Microarrays: This test can determine the copy number of sequences in the genome, including the detection of deletions or duplications in chromosome 1 [5].
• Targeted Deletion Analysis by Fluorescence In Situ Hybridization (FISH): This test can specifically detect the deletion in chromosome 1q21.1 region [5].
• Standard Karyotype and Chromosomal Microarray Analyses: These tests can be performed to detect genetic disorders associated with abnormal findings, including chromosome 1q21.1 deletion syndrome [6].

Early Detection

In some cases, parents may have normal chromosomes by a blood test, but a few of their egg or sperm cells may carry the microdeletion. This is known as germline mosaicism, which can increase the risk of passing on the condition to offspring [4].

References:

• [1] Oct 1, 2012 — In these individuals, the microdeletion is often detected when they undergo genetic testing because they have a relative with the chromosomal ...
• [2] Feb 24, 2011 — The diagnosis of the 1q21.1 recurrent deletion is established by the detection of the recurrent distal heterozygous deletion between BP3 and BP4 ...
• [5] 1 deletion. The copy number of sequences can be determined using chromosome microarrays or targeted deletion analysis by fluorescence in situ hybridization.
• [6] by YH Kim · 2018 · Cited by 1 — Standard karyotype and chromosomal microarray analyses were performed to detect genetic disorders associated with a series of abnormal findings ...
• [4] Very rarely (less than 1%), both parents have normal chromosomes by a blood test, but a few of their egg or sperm cells carry the microdeletion. This is ...

Current Treatment Options for Chromosome 1q21.1 Deletion Syndrome

Unfortunately, there are no specific medicines designed to treat 1q21.1 deletion syndrome directly [5]. However, a genetic diagnosis can help individuals and their families make informed decisions about the best way to manage the condition.

• Genetic Counseling: Genetic counseling is an essential part of managing chromosome 1q21.1 deletion syndrome. It involves discussing the risks and benefits of various medical interventions with a healthcare professional [3].
• Multidisciplinary Care: Individuals with 1q21.1 deletion syndrome often require a multidisciplinary approach to care, involving specialists such as geneticists, psychologists, and other healthcare professionals [7].

Current Research and Future Directions

While there are no specific treatments for chromosome 1q21.1 deletion syndrome, researchers continue to explore new avenues of investigation.

• Gene Therapy: Gene therapy is a promising area of research that may potentially lead to the development of targeted therapies for individuals with 1q21.1 deletion syndrome [8].
• Pharmacological Interventions: Researchers are also exploring pharmacological interventions that may help alleviate symptoms associated with chromosome 1q21.1 deletion syndrome.

Important Considerations

It is essential to consult with a healthcare professional for medical advice and treatment regarding chromosome 1q21.1 deletion syndrome [6].

References:

[3] GeneReviews provides clinical information on genetic diseases, including diagnosis, treatment, and genetic counseling. [5] At this point, there are no medicines designed to treat 1q21.1 deletion syndrome. [6] Please consult with a healthcare professional for medical advice and treatment. [7] 1q21.1 microdeletion syndrome is a newly described recurrent deletion syndrome with variable clinical manifestations but without the clinical picture of other syndromes. [8] by CA Bacino · Cited by 2 — INTRODUCTION. Chromosome deletions that span at least 5 megabases (Mb) are usually microscopically visible on chromosome-banded karyotypes.

Chromosome 1q21.1 deletion syndrome, also known as 1q21.1 microdeletion syndrome, is a rare genetic disorder caused by the deletion of a small piece of chromosome 1. The differential diagnosis for this condition involves considering other genetic disorders that may present with similar symptoms.

Similarities with TAR Syndrome

TAR (Thrombocytopenia-Absent Radius) syndrome is another genetic disorder that can be confused with 1q21.1 deletion syndrome due to overlapping symptoms