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Publication
Microarray in clinical practice – utility vs complexity. Mixed phenotype of duplication 15q11.2q13.1 and deletion 16p11.2
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Advisor(s)
Abstract(s)
Introduction: There’s a consensus to perform chromosomal microarray
technique as first-tier clinical diagnostic test for individuals with developmental
disabilities. However, given the complexity of clinical presentations, often several
diagnostic methods are held before conducting microarray.
Method: We report the case of a 5 year-old boy referred to Medical Genetics due
to short stature, developmental disabilities and facial dysmorphic features.
He was born from eutocic delivery after an uneventful pregnancy. He had
psychomotor milestones delayed like sitting at 9 months and walking at 24
months, holding an immature broad-based gait. There was history of learning
difficulties from both parents, and the mother has also short stature.
On examination it was noted some facial dysmorphic features like high forehead,
conical canines and rarefaction of the distal portion of the eyebrows.
Due to the history of an episode of transient ataxia, and suspicion of an inherited
metabolic disorder, he had already performed various analytical and imaging
screenings, all normal.
Results: Chromosomal microarray analysis revealed two pathogenic Copy
Number Variants (CNV’s): 16p11.2 deletion and 15q11.2q13.1 duplication.
The 15q11q13 microduplication syndrome (OMIM # 608636) is a very rare clinical
entity with about 30 reported cases with maternal origin, and it is characterized by
neurobehavioral disorder, hypotonia, cognitive impairment, epilepsy and short
stature.
The 16p11.2 microdeletion syndrome (OMIM # 613444) is also a rare clinical
entity, with high penetrance, associated with obesity and developmental
disabilities.
Discussion: Despite the unquestionable utility of microarray, the correlation of
the CNV's with the phenotype is often difficult by the rarity of these new
microdeletion/duplication clinical entities. In this case the interpretation has
increased difficulty because of the simultaneous existence of two distinct clinical
entities. Segregation studies, which in the first step include parental analysis, are
essential for genetic counseling and determining the risk of recurrence but also
for a more accurate correlation genotype-phenotype.
Description
Keywords
Doenças genéticas Duplicação Deleção 15q11.2q13.1 16p11.2 Microarray Doenças Genéticas