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AIS, or androgen insensitivity syndrome, is a rare genetic disorder that disrupts sexual maturation in people who are destined to be men. Individuals with AIS are XY chromosome-positive (genetic males), however they do not respond normally to androgens (male sexual development hormones). Individuals with AIS may have external genitalia that do not conform to the standards of either sex and may have secondary sexual traits like facial and pubic hair that are incompletely developed. Furthermore, they could experience a wide range of hormonal and reproductive problems.

Androgen Insensitivity Syndrome :‎ [MEDNOTES+MINDMAP]

  • Definition: rare genetic disorder that causes individuals to be insensitive to androgens (male hormones)
    • Individuals with AIS have XY chromosomes (typically associated with males) but have external genitalia that appear female
    • AIS can range in severity, with some individuals experiencing mild symptoms and others experiencing severe symptoms
  • Epidemiology: estimated to affect 1 in 20,000-50,000 individuals
    • AIS is more common in certain populations, including people of Middle Eastern and North African descent
    • AIS is also more common in certain families with a history of the disorder
  • Natural history: AIS is a lifelong condition that is present from birth
    • Symptoms may vary in severity and may not be noticeable until puberty
    • Some individuals with AIS may not be diagnosed until adulthood
  • Types: AIS is classified into three types based on severity
    • Complete androgen insensitivity syndrome (CAIS): individuals with CAIS do not produce any androgens and have fully female external genitalia
    • Partial androgen insensitivity syndrome (PAIS): individuals with PAIS produce some androgens and have ambiguous genitalia
    • Mild androgen insensitivity syndrome (MAIS): individuals with MAIS produce androgens and have male external genitalia, but may experience mild symptoms such as infertility or breast development.
  • Risk Factors:

    • Genetic mutation that causes AIS is passed down from a parent to their child
    • AIS can occur in individuals of any ethnicity or gender
  • Etiology/Causes:

    • AIS is caused by a mutation in the androgen receptor gene, which is responsible for the development of male characteristics in the body
    • This mutation can cause the androgen receptors to be non-functional or not present at all, leading to a lack of response to androgens (male hormones) in the body
  • Signs:

    • Lack of development of male secondary sexual characteristics, such as facial hair, deep voice, and broad shoulders
    • Incomplete development of the external genitalia in males (micropenis or undescended testicles)
    • In females, external genitalia may appear normal
  • Symptoms:

    • Infertility in males due to underdeveloped reproductive organs
    • Infertility in females may also occur due to lack of development of the uterus and fallopian tubes
    • Incomplete or absent development of pubic and underarm hair
    • Short stature
    • Weak muscles and bone
  • Diagnosis

    • Clinical evaluation by a neurologist
    • MRI or CT scan to rule out brain lesions or damage
    • Electroencephalogram (EEG) to measure brain activity
    • Neuropsychological testing to assess cognitive function
    • Genetic testing may be conducted in cases of genetic disorders as a cause
  • Tests Required

    • Physical examination
    • Neurological examination
    • Imaging tests (MRI or CT scan)
    • EEG
    • Neuropsychological testing
    • Genetic testing (if applicable)
  • Associated with

    • Brain damage or lesion in the corpus callosum (the area connecting the left and right hemispheres of the brain)
    • Traumatic brain injury
    • Stroke
    • Brain tumors
    • Neurodegenerative disorders (such as Alzheimer’s disease or Parkinson’s disease)
    • Genetic disorders (such as Down syndrome)
  • Similar diseases/syndromes

    • Apraxia (inability to perform purposeful movements)
    • Dyspraxia (difficulty planning and performing movements)
    • Neglect syndrome (inability to recognize or attend to one side of the body or environment)
  • Treatment

    • Occupational therapy to improve fine motor skills and coordination
    • Cognitive behavioral therapy to address any psychological issues related to the condition
    • Medications to improve brain function and communication between the brain hemispheres (such as anticonvulsants or antidepressants)
    • Surgical intervention (such as corpus callosotomy) may be considered in severe cases to sever the connection between the brain hemispheres and reduce involuntary movement.

Dr. Arin Nandi

Passionate About Medical Science & Helping Future Doctors Achieve Top Ranks In Medical Exams. He is professionally a dentist as well as a public health expert from JIPMER working in govt.health department
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