non-syndromic X-linked intellectual disability 63

Non-syndromic X-linked intellectual disability (NS-XLID) refers to a group of genetic disorders that affect only males and are characterized by intellectual disability without any other symptoms or signs. NS-XLID is caused by mutations in genes located on the X chromosome, which is one of the two sex chromosomes.

• Prevalence: The prevalence of NS-XLID is unknown, as it is a rare condition.
• Inheritance: NS-XLID is inherited in an X-linked recessive pattern, meaning that the mutated gene is located on the X chromosome and only males can be affected. Females are typically carriers of the mutated gene but usually do not show symptoms themselves.
• Age of onset: The age of onset for NS-XLID varies, but it often becomes apparent in childhood or infancy.

There are several types of NS-XLID, each caused by mutations in different genes. Some of these include:

• MID2-related NS-XLID: This type is caused by a mutation in the MID2 gene and is characterized by moderate intellectual disability and impaired speech.
• NEXMIF-related NS-XLID: This type is associated with non-syndromic X-linked intellectual disability and its clinical features, as well as available genetic tests from the US.

It's worth noting that NS-XLID can have a significant impact on an individual's quality of life, affecting their cognitive abilities, communication skills, and overall well-being. However, with proper support and accommodations, many individuals with NS-XLID are able to lead fulfilling lives and participate in various activities.

References:

• [1] - This review focuses on the current knowledge on the XLID genes involved in non-syndromic forms, with the emphasis on their pathogenic mechanism, thus allowing for a better understanding of the condition.
• [10] - A number of X-linked genes cause NS-ID as the predominant phenotype, and several of these are relatively common in comparison to most NS-ID cases.

**Understanding Nonspecific X-linked Intellectual

Non-syndromic X-linked intellectual disability (NS-XLID) can be challenging to diagnose due to its complex nature and the involvement of multiple genes on the X-chromosome. However, there are several differential diagnoses that should be considered when evaluating individuals with NS-XLID.

Other forms of X-linked ID

• Other forms of X-linked intellectual disability should be ruled out as they may present with similar symptoms [3].
• These include other syndromes such as Börjeson-Forssman-Lehmann syndrome, Wilson-Turner syndrome, and Smith-Fineman-Myers syndrome [6].

Autism Spectrum Disorder

• Autism spectrum disorder (ASD) can be a differential diagnosis for NS-XLID, particularly in females who may present with mild to moderate intellectual disability and autistic features [5].

Borderline intellectual functioning

• Borderline intellectual functioning is another condition that should be considered in the differential diagnosis of NS-XLID, as it may present with similar symptoms such as mild to moderate intellectual disability [5].

Child Abuse & Neglect, Posttraumatic Stress Disorder

• Child abuse and neglect, as well as posttraumatic stress disorder (PTSD), can also be differential diagnoses for NS-XLID, particularly in cases where there is a history of trauma or abuse [5].

Other X-linked intellectual disability syndromes

• Other X-linked intellectual disability syndromes that involve similar symptoms or clinical findings should also be considered in the differential diagnosis of NS-XLID [7].

It's essential to note that a comprehensive evaluation, including genetic testing and a thorough medical history, is necessary to accurately diagnose NS-XLID and rule out other potential causes.

References: [3] Nonsyndromic XLID is characterized by intellectual disability in the absence of other symptoms... Other differential diagnoses include other forms of X-linked ID... [5] Nov 16, 2021 — Differential Diagnoses · Autism Spectrum Disorder · Borderline intellectual functioning · Child Abuse & Neglect, Posttraumatic Stress Disorder. [6] Differential diagnosis. Differential diagnosis includes Börjeson-Forssman-Lehmann syndrome, Wilson-Turner syndrome and Smith-Fineman-Myers syndrome. [7] The main differential diagnosis options include other X-linked intellectual disability syndromes that involve similar symptoms or clinical findings.