Slides to accompany RALLI presentation: An extra X or Y chromosome: a rare cause of language impairment. see http://www.youtube.com/RALLIcampaign/

1. 1
The effect of an extra X or Y
chromosome on language
development
Dorothy V. M. Bishop

2. 2
Human chromosomes
One of each pair inherited from mother, one from father
X and Y are sex
chromosomes:
usually XX in girls
and XY in boys

3. 3
Extra X or Y chromosome
• 47, XXX (trisomy X, triple X syndrome)
– affects 1 per 1000 girls
• XXY – Klinefelter’s syndrome
– affects 1 per 650 boys
• XYY
– affects 1 per 1000 boys

4. 4
How is extra X or Y chromosome detected?
• Requires a blood test
• Often it is NOT detected because children look normal
and don’t have major problems
• May be picked up on prenatal screening
• May be picked up if child is tested because of
educational difficulties
• XXY can be detected because child doesn’t experience
normal changes of puberty; or may be identified in
adulthood during investigations for infertility

5. 5
What features are associated with having an
extra X or Y chromosome? (1)
N.B. Huge variation from child to child: no one feature is found
in all. Some affected children have NO problems
•Features documented in research studies for all three
trisomies:
– Children tend to be taller than usual
– Speech and language difficulties are common
– Mild autistic features (more severe autism in a minority)
– Poor muscle tone
– Social anxiety: esp. in XXX and XXY – extremely shy and worried
about talking in public
– Social immaturity: prefers company of younger children; may be
‘easily led’ by older children

6. 6
What features are associated with having an
extra X or Y chromosome? (2)
• Features noted in parent reports, but not much hard data
and unclear how common:
– Dental problems
– ‘Growing pains’ in arms and legs
– Hypersensitivity to touch - makes choice of clothes an issue
– “Meltdowns” – sudden explosions of rage which go as quickly as
they come
Specific to Klinefelter syndrome (XXY)
– Failure to go through puberty; infertility in adulthood
N.B. Puberty/fertility usually normal in XXX and XYY

7. 7
Research on sex chromosome
trisomies
• 1960s: Newborn screening studies done to look
at unbiased samples
• Most children attend mainstream school
• But increased educational difficulties, especially
affecting language, in all three trisomies, though
with some differences in cognitive profile.
Leggett, V., Jacobs, P., Nation, K., Scerif, G., & Bishop, D. V. M. (2010). Neurocognitive
outcomes of individuals with a sex chromosome trisomy: XXX, XYY, or XXY: a
systematic review. Developmental Medicine and Child Neurology, 52(2), 119-129. doi:
10.1111/j.1469-8749.2009.03545.x

8. 8
Recent study based on parental
interviews and questionnaires
Bishop, D. V. M., et al (2011). Autism, language and communication in
children with sex chromosome trisomies. Archives of Disease in Childhood,
96, 954-959. doi: doi:10.1136/adc.2009.179747
Children identified on prenatal screening or in first year
of life
•30 with XXX
•19 with XXY
•21 with XYY
Compared with brothers and sisters in same age range
(4 to 15 yr)

9. 9
Rates of reported educational problems
Substantial
individual
variation
XXX XXY XYY
Special educational
needs
14% 32% 48%
Speech and
language therapy
24% 47% 71%
Autism spectrum
disorder diagnosis
0% 11% 20%
Rates of SEN and SALT generally higher than in general population or in
brothers and sisters. ASD rate in boys contrasts with around 1.6% in
general population

10. 10
Is sex chromosome trisomy a common
cause of language impairment/autism?
NO!
•Konstantareas & Homatidis (1999)
– series of 127 children diagnosed with autism
• One case of XXY (and 7 with other chromosome anomalies)
•Robinson (1991)
– 65 boys and 17 girls with SLI
• Three cases of XXY
These rates are higher than in the general population,
but the majority of children with language impairment
or autism have the usual number of chromosomes,
46.

11. 11
More information on the web
N.B. Quality of information on the web is very variable, and
some of it highly inaccurate.
These are reliable sources:
Unique: http://www.rarechromo.co.uk/html/home.asp
for information on trisomy X and XYY
Klinefelter’s syndrome association UK: http://www.ksa-uk.net/
KS&A (USA) http://www.genetic.org/

12. For further reading
see reference list on:
http://www.slideshare.net/RALLICampaign/an-
extra-x-or-y-chromosome