Genotype-phenotype correlation in 22q11.2 deletion syndrome

Elena Michaelovsky, Amos Frisch*, Miri Carmel, Miriam Patya, Omer Zarchi, Tamar Green, Lina Basel-Vanagaite, Abraham Weizman, Doron Gothelf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

81 Scopus citations

Abstract

Background: The 22q11.2 deletion syndrome (22q11.2DS) is caused by hemizygous microdeletions on chromosome 22q11.2 with highly variable physical and neuropsychiatric manifestations. We explored the genotype-phenotype relationship in a relatively large 22q11.2DS cohort treated and monitored in our clinic using comprehensive clinical evaluation and detailed molecular characterization of the deletion.Methods: Molecular analyses in 142 subjects with 22q11.2DS features were performed by FISH and MLPA methods. Participants underwent clinical assessment of physical symptoms and structured psychiatric and cognitive evaluation.Results: Deletions were found in 110 individuals including one with an atypical nested distal deletion which was missed by the FISH test. Most subjects (88.2%) carried the 3Mb typically deleted region and 11.8% carried 4 types of deletions differing in size and location. No statistically significant genotype-phenotype correlations were found between deletion type and clinical data although some differences in hypocalcemia and cardiovascular anomalies were noted.Analysis of the patient with the distal nested deletion suggested a redundancy of genes causing the physical and neuropsychiatric phenotype in 22q11.2DS and indicating that the psychiatric and cognitive trajectories may be governed by different genes.Conclusions: MLPA is a useful and affordable molecular method combining accurate diagnosis and detailed deletion characterization. Variations in deletion type and clinical manifestations impede the detection of significant differences in samples of moderate size, but analysis of individuals with unique deletions may provide insight into the underlying biological mechanisms.Future genotype-phenotype studies should involve large multicenter collaborations employing uniform clinical standards and high-resolution molecular methods.

Original languageEnglish
Article number122
JournalBMC Medical Genetics
Volume13
DOIs
StatePublished - 17 Dec 2012

Funding

FundersFunder number
March of Dimes Foundation5-FY06-590

    Keywords

    • Copy number variation (CNV)
    • Molecular diagnosis
    • Multiplex ligation probe amplification (MLPA)
    • Neuropsychiatric disorders
    • Velocardiofacial syndrome (VCFS)

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