Page 164 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

Chapter 5
Another common finding in 22q11.2DS was posterior embryotoxon (22-
50%), that also has a higher prevalence compared to the general population
(7%).46 As proposed by others, posterior embryotoxon and other anterior
segment abnormalities may be a result of defects in migration, proliferation
and differentiation of neural crest cells in an early embryologic stage in
22q11.2DS.7, 9, 47 Anterior segment dysgenesis may increase the risk of
glaucoma, which was reported only once in the included review studies9
and in not a single patient in our cohort. Other findings supporting a role of
a 22q11.2 deletion in anterior segment dysgenesis were scarce, including
Peter’s anomaly, iris remnants and lens opacities.7, 9
With advances in clinical genetic testing, ophthalmic screening is no longer
important for diagnosing 22q11.2DS. Another reason for screening after
birth could be an increased prevalence of congenital cataract because of
its impact on the development of the visual system. However, based on
our results, we cannot conclude that congenital cataract has a higher
prevalence in 22q11.2DS compared to the general population.
Table 4. Recommendations for ophthalmic and orthoptic screening in 22q11.2DS.
Assessment At diagnosis At three years old At adulthood
√ √
√ √
Strabismus Amblyopia Refractive errors Visual acuity √ √ Low-threshold
√ √ Low-threshold
Each √ refers to a single assessment with follow-up as needed. Ophthalmic screening should be
done at least once by an ophthalmologist.
We would recommend that children with 22q11.2DS receive screening
by an ophthalmologist and orthoptist at the age of three years in order
to detect and treat strabismus, amblyopia and refractive errors, which
have high prevalence rates in 22q11.2DS. From the age of three years a
reliable monocular VA measurement should be possible. Also, detection of
amblyopia is important at an early age because of reduced plasticity of the
visual cortex after the age of 7 years. Patients diagnosed with 22q11.2DS
after the age of three years should receive ophthalmic and orthoptic
screening at diagnosis with follow-up as needed.
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