8a. Klinefelter Syndrome

Question 1

Which karyotypes stands for which disorder?

• 47,XXX
• 47,XXY
• 47,XYY

Answer 1

• 47,XXX –> Triple X / Trisomy X (females)
• 47,XXY –> Klinefelter (males)
• 47,XYY –> Jacob’s (males)

Question 2

Architecture of the brain

Which 2 consistent findings?

And which 2 predicted, but inconsistent findings?

Answer 2

Consistent findings:

• Global and regional brain volumetric differences (with a tendency of smaller volumes in Klinefelter patients)
• Decreased cerebellar volume

Inconsistent findings:

• Hemispheric asymmetry: language is more often found in the left hemisphere and the language hypothesis sais that having an asymmetric brain may explain why participants with an extra X chromosome will show some language difficulties (so lateralization problems)
• Subcortical structures: due to decreased volumes of the amygdala and hypothalamus may explain the emotional problems

Question 3

Where is functional neuroimaging mostly focused on? (3x)

And in which domains are there differences found? (4x)

Answer 3

On EF, language processing/lateralization, and social cognition

Differences:

• Behavioral adaptation
• Emotion & motivation
• Social attribution
• Social perception

Question 4

Which 4 cognitive domains are suspeted to impact Klinefelter patients?

Answer 4

1. Cognition/intelligence
2. Language
3. EF
4. Social cognition

Question 5

What is the difference in cognition?

Answer 5

IQ is usually around borderline or at the lower end of the normal range (shift to the left with around 10 points of IQ score less than controls).

Intellectual disabilities are uncommon.

When you look at specific profiles, most often verbal scales are impacted.

Question 6

What is the difference in language?

Answer 6

one of the main difficulties in Klinefelter (70-80%) and present from a young age:

• Smaller vocabulary size
• Difficulty in lexicon use
• Use of gestures

These may include:

• Receptive (understand) and expressive (doing it) communication skills
• Communication in general (verbal/non-verbal skills)
• Pragmatics (the use of language in social situations –> reading the room, grasping sarcasm or irony)

Question 7

What is the difference in EF? (6x)

Answer 7

Difficulties with:

• WM
• Inhibition
• Mental flexibility
• Strategic planning
• Fluency
• Attention regulation

Most research has been done on WM and fluency, since these tend to be also language based tasks. About 25-50% score clinically impaired.

Question 8

What is the impact of EF difficulties in day-to-day life? (4x)

Answer 8

• It has been related to daily life difficulties (as observed by the parents)
• It show variability with age, with different skills being differently impaired around different ages
• More pronounced in the context of early life stressors
• Less EF performance has been associated with psychopathology (ASD, ADHD, externalizing and psychotic problems. So, there has been a link between EF functioning and socio-emotional problems in Klinefelter.

Question 9

What is the difference in social cognition?

Answer 9

Difficulties with:

• Emotion recognition (face and voices)
• Less developed ToM
• Lesser social attention (reading gaze, looking at eye movements) –> compared to controls, fixation duration was different for the eyes in which Klinefelter children have less fixation duration than controls.

Question 10

What is the difference in social, emotional, and behavioral problems?

Answer 10

Around 25% has an increased risk for psychopathology (autism, ADHD, psychotic symptoms, anxiety, depression).

Klinefelter children fall within the ‘moderate’ category of ASD symptoms, while ASD children fall of course in the ‘severe’ category.