Unique Combination of 22q11 and 14qter Microdeletion Syndromes Detected Using Oligonucleotide Array-CGH

Area of Science:

• Genetics
• Human Biology
• Pediatrics

Background:

• 22q11 deletion syndrome is a common genetic disorder with variable clinical manifestations.
• 14q terminal deletion syndrome is a rare chromosomal abnormality associated with distinct facial features and developmental issues.
• Co-occurrence of multiple chromosomal abnormalities can complicate diagnosis and management.

Purpose of the Study:

• To report and characterize a unique case of a pediatric patient with a concurrent 22q11 deletion and 14q terminal deletion.
• To investigate the genetic basis and inheritance pattern of these combined chromosomal abnormalities.
• To correlate the genotype with the observed clinical phenotype.

Main Methods:

• Karyotyping using G-banding and fluorescence in situ hybridization (FISH).
• Comparative genomic hybridization on oligonucleotide-based microarray (array-CGH) for precise deletion mapping.
• Clinical examination and assessment of familial genetic status.

Main Results:

• The proband presented with features of 22q11 deletion syndrome but lacked typical immunodeficiency.
• Genetic analyses revealed a karyotype of 45,XY,der(14)t(14;22)(q32.3;q11.2),-22, with deletions at 22q11.21 (∼4.25 Mb) and 14q32.33qter (∼3.24 Mb).
• The mother carried a balanced translocation with a deleted 14q telomere and exhibited mild symptoms consistent with terminal 14q deletion syndrome.

Conclusions:

• This case highlights the possibility of co-occurring 22q11 deletion and 14q terminal deletion syndromes.
• Array-CGH is crucial for accurate diagnosis and delineation of complex chromosomal rearrangements.
• The study emphasizes the phenotypic variability within these syndromes and the importance of comprehensive genetic evaluation.