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Microduplication 3p26.3p24.3 and 4q34.3q35.2 Microdeletion Identified in a Patient with Developmental Delay

Georgeta Cardos1, Nicolae Gica1,2, Corina Gica1,2

  • 1Filantropia Clinical Hospital, 011132 Bucharest, Romania.

Diagnostics (Basel, Switzerland)
|November 26, 2022
PubMed

Insights

Molecular karyotyping analysis (MCA) detects microdeletions and microduplications, aiding the diagnosis of rare genetic diseases. SNP-array MCA identified specific genomic imbalances in a child with developmental delay and brain malformations.

Area of Science:

  • Genetics
  • Developmental Biology
  • Medical Diagnostics

Background:

  • Microdeletions and microduplications are key factors in multiple congenital malformations (MCM), developmental delay/intellectual disability (DD/ID), and autism spectrum disorders (ASD).
  • Molecular karyotyping analysis (MCA) using DNA microarray technology is crucial for diagnosing rare genetic diseases caused by copy number variations (CNVs).
  • MCA offers higher resolution than traditional G-banded karyotyping for detecting microdeletions and microduplications, identifying approximately 10% more pathogenic genomic imbalances.

Purpose of the Study:

  • To highlight the diagnostic utility of MCA, particularly SNP-array, in identifying pathogenic genomic imbalances.
  • To present a case study illustrating the application of MCA in diagnosing a child with complex developmental and neurological abnormalities.
  • To emphasize the role of MCA in precise etiological diagnosis of rare genetic disorders.

Main Methods:

  • Utilized Molecular Karyotyping Analysis (MCA) via Single Nucleotide Polymorphism-array (SNP-array).
  • Applied MCA as a first-tier diagnostic test for patients presenting with MCM, DD/ID, or ASD.
  • Performed comprehensive genetic analysis to detect copy number variations (CNVs) and identify regions of loss of heterozygosity and uniparental disomy.

Main Results:

  • MCA identified a 3p26.3p24.3 microduplication and a 4q34.3q35.2 microdeletion in a five-year-old patient.
  • These specific genomic imbalances were found to be the underlying cause of the patient's global developmental delay, bilateral fronto-parietal lysencephaly, and pachygyria.
  • SNP-array MCA successfully elucidated the genetic basis of the patient's phenotype, enabling a precise diagnosis.

Conclusions:

  • MCA, especially SNP-array, is a powerful tool for diagnosing genetic disorders associated with CNVs.
  • The precise identification of microdeletions and microduplications through MCA is essential for understanding disease etiology and establishing accurate diagnoses.
  • This case underscores the clinical significance of MCA in pediatric genetics, particularly for complex neurodevelopmental disorders.
Keywords:
SNP-arrayintellectual disabilitymolecular karyotyping

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