non-syndromic X-linked intellectual disability 93

Non-syndromic X-linked intellectual disability (NS-XLMR) refers to a condition where males have intellectual disability without any additional physical, neurological, or psychiatric symptoms. This type of intellectual disability is caused by mutations in genes located on the X-chromosome.

According to various sources [10][12][14], NS-XLMR is characterized by:

• Intellectual disability as the only symptom
• No associated physical, neurological, or psychiatric manifestations
• Males are more heavily affected than females, who tend to have milder symptoms due to having one normal X chromosome

There are approximately 40 genes known to cause NS-ID, and ~80% of these reside on the X-chromosome [10]. The new genes were identified by sequencing of candidate genes, the entire X-chromosome, the whole exome, or the whole genome [15].

It's worth noting that non-syndromic intellectual disabilities are typified by a lack of other abnormalities (syndromic X-linked intellectual developmental disabilities are generally associated with additional symptoms) [9].

Non-syndromic X-linked intellectual disability (NS-XLMR) is a condition characterized by intellectual disability in the absence of other symptoms or signs. The signs and symptoms of NS-XLMR can vary from person to person, but here are some common features:

• Intellectual Disability: The most prominent feature of NS-XLMR is intellectual disability, which can range from mild to severe.
• Weak Muscle Tone (Hypotonia): Many individuals with NS-XLMR have weak muscle tone, which can delay motor skills such as sitting, standing, and walking [9].
• Abnormal Head or Neck: Some people with NS-XLMR may have abnormalities of the head or neck, such as bifid uvula or high palate [6].
• Eye Abnormalities: Strabismus (crossed eyes) is a common eye abnormality associated with NS-XLMR [6].
• Genitourinary System Abnormalities: Enuresis (bedwetting) and other genitourinary system abnormalities have been reported in individuals with NS-XLMR [6].

It's essential to note that not everyone with NS-XLMR will exhibit all of these signs and symptoms, and the severity can vary widely from person to person. Additionally, some individuals may have no noticeable physical or behavioral abnormalities despite having intellectual disability.

References:

[6] - Abnormality of head or neck, bifid uvula; High palate [9] - Most affected children have weak muscle tone (hypotonia), which delays motor skills such as sitting, standing, and walking. [6] - Abnormality of the eye. Strabismus

Non-syndromic X-linked intellectual disability (NS-XLMR) can be challenging to diagnose, but various diagnostic tests are available to help identify the condition.

• Chromosomal Microarray Analysis (CMA): This is a recommended first-line genetic test for children with NS-XLMR. CMA can detect deletions or duplications of genetic material on the X chromosome that may contribute to the condition [5].
• Genetic Testing: Genetic testing can help diagnose the specific type of intellectual disability present and guide treatment. Early intervention can significantly benefit individuals with NS-XLMR [9].
• Karyotype Analysis: This test examines the number and structure of chromosomes, which can reveal abnormalities that may contribute to NS-XLMR.
• Fragile X Syndrome Testing: Fragile X syndrome is a specific type of intellectual disability caused by mutations in the FMR1 gene. Testing for this condition can help rule out other causes of NS-XLMR.

It's essential to note that genetic testing should be performed by a qualified medical professional, and results should be interpreted in the context of individual patient characteristics and family history.

References:

[5] - Chromosomal microarray analysis (CMA) is recommended as a first-line genetic test for children with intellectual disability [5]. [9] - Genetic testing can help diagnose the specific type of intellectual disability present and guide treatment [9].

Non-syndromic X-linked intellectual disability (NS-XLID) is a condition characterized by specific cognitive deficits that can affect social memory, without other major pathophysiology. While there are no specific drugs approved for the treatment of NS-XLID, research has explored various pharmacological interventions to alleviate symptoms.

• Minocycline, an antibiotic of the tetracycline class, has been investigated as a potential treatment for Fragile X Syndrome (FXS), a form of NS-XLID [6]. However, its efficacy in treating other forms of NS-XLID is unclear.
• Antiepileptic drugs have been used to manage seizures associated with NS-XLID. The selection of the drug is based on the specific seizure type and underlying cause [11].
• Other potential therapeutic targets for NS-XLID include genes involved in synaptic plasticity, such as CNKSR2, which has been implicated in non-syndromic X-linked intellectual disability [14].

It's essential to note that these findings are based on research studies and may not be directly applicable to individual cases. Treatment decisions should be made in consultation with a qualified healthcare professional.

References: [6] Minocycline as a treatment for FXS animal models. [11] General principles for antiepileptic drug treatment. [14] Loss-of-Function CNKSR2 Mutation Is a Likely Cause of Non-Syndromic X-Linked Intellectual Disability.

Non-syndromic X-linked intellectual disability (NS-XLID) refers to a condition where individuals exhibit intellectual disability without any additional clinical symptoms or physical anomalies. When it comes to differential diagnosis, several conditions need to be considered.

Other forms of X-linked ID: NS-XLID is characterized by intellectual disability in the absence of other symptoms [4]. Other differential diagnoses include other forms of X-linked ID, which can present with similar symptoms or clinical findings [9].

Fragile X syndrome: Fragile X syndrome is a genetic disorder caused by mutations in the FMR1 gene. It is the most common form of intellectual disability and affects approximately 1:5000 males [13]. Females are usually non- or mildly affected.

DDX3X-related neurodevelopmental disorder: DDX3X-related neurodevelopmental disorder (DDX3X-NDD) typically occurs in females and very rarely in males [5].

Autism Spectrum Disorder, Borderline intellectual functioning, Child Abuse & Neglect, Posttraumatic Stress Disorder: These conditions can also be considered in the differential diagnosis of NS-XLID, particularly when additional clinical symptoms or physical anomalies are present [6].

Börjeson-Forssman-Lehmann syndrome, Wilson-Turner syndrome, Smith-Fineman-Myers syndrome: These syndromes are rare genetic disorders that can present with intellectual disability and other clinical features. They should be considered in the differential diagnosis of NS-XLID [7].

It's essential to note that non-syndromic X-linked intellectual disability is a complex neurodevelopmental disorder, and a comprehensive evaluation by a qualified healthcare professional is necessary for accurate diagnosis and management.

References: [4] Non-syndromic XLID is characterized by intellectual disability in the absence of other symptoms. [5] DDX3X-related neurodevelopmental disorder (DDX3X-NDD) typically occurs in females and very rarely in males. [6] Autism Spectrum Disorder, Borderline intellectual functioning, Child Abuse & Neglect, Posttraumatic Stress Disorder. [7] Börjeson-Forssman-Lehmann syndrome, Wilson-Turner syndrome, Smith-Fineman-Myers syndrome. [9] The main differential diagnosis options include other X-linked intellectual disability syndromes that involve similar symptoms or clinical findings. [13] Intellectual disability (ID) affects 1–3% of the Western population and is heterogeneous in origin. Mutations in X-linked genes represent 5–10% of ID in males.