XLID98

(X-Linked Intellectual Disability #98)

X-linked intellectual developmental disorder-98 (XLID98) is a neurodevelopmental disorder primarily characterized by Autism, Intellectual Disability, and Epilepsy.

X-Linked Intellectual Disability- 98 (XLID98) is a genetic condition that affects the growth and function of neurons in the central nervous system (CNS), especially the brain, caused by a mutation in the NEXMIF gene. The name of the gene, NEXMIF reflects the function of the gene – Neurite Extension and Migration Factor. XLID98 is a neurodevelopmental disorder that begins prior to birth and has no known cure as of 2024.  There is no information that suggests that XLID98 has any impact on the life expectancy of the affected person.  As of 2024, we have learned a lot about the condition, but still have so much to learn.  Only a small handful of researchers and medical professionals worldwide have experience with this condition.  The XLID98 Foundation is instrumental in developing the only data registry specific to understanding this condition and what happens as the person with XLID98 gets older.  The only information available about howXLID98 may change as an individual gets older is from the personal reports from families, which is why it is so important to build a community of people who have experience with XLID98.  We are not alone!

What does XLID98 look like?

Although we are still learning of the many ways that people with XLID98 are affected, there is some early research that has identified some common characteristics.  It is important to remember that not everyone with this condition has difficulties in every area and some people are more severely affected in some areas than others. In fact, some individuals may not show significant symptoms of the 3 characteristics most common in the condition. At this time, we do not have empirical evidence of the prevalence, severity, and developmental progression of the symptoms of XLID98.  Below is a list of some of the ways the XLID98 negatively affects individuals as specified in OMIM.ORG (Online Mendelian Inheritance in Man) the catalog of Human Genes and Genetic disorders used by Geneticists and Medical Professionals.
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Some of the common areas of difficulty identified in this condition are:

a. Intellectual Disability
b. Epilepsy (For example: Myoclonic, Absence, Generalized, Status Epilepticus, Tonic-Clonic, Atonic, Eyelid-flutter, Tonic, Hypsarrhythmia-infantile spasms)
c. Autism Spectrum Disorder (For Example: Repetitive movements, stereotypical hand movements, communication difficulties, social difficulties)

Other areas that have been identified in some individuals include:

It is important to keep in mind that not all individuals show the same presentation, but we tend to see some differences between how XLID98 affects males and females.   For example, females tend to have more difficulties with seizures, including intractable seizures.  On the other side, males tend to have greater difficulties with communication and intellectual development.  There is still so much to learn about the cause and long-term developmental patterns of these symptom presentations.