A PATIENT WITH PARTIAL CHROMOSOME 12q DUPLICATION AND 10q DELETION

Area of Science:

• Genetics
• Cytogenetics
• Molecular Biology

Background:

• Chromosomal abnormalities, including deletions and duplications, are common causes of various clinical phenotypes.
• Conventional karyotyping may not detect all candidate genes responsible for complex genetic disorders.
• Advanced analytical technologies like array-CGH improve the detection of submicroscopic chromosomal alterations.

Observation:

• An 18-month-old girl presented with prenatal and postnatal growth retardation, secundum atrial septal defect (ASD), patent ductus arteriosus (PDA), and distinctive facial dysmorphic features.
• Chromosome analysis revealed a complex karyotype: 46,XX del(10)(q26.3),dup(12)(q24.11-q24.33) dn.
• Facial dysmorphia included frontal bossing, arched eyebrows, hypertelorism, and a wide nasal bridge, alongside chronic diarrhea.

Findings:

• Array comparative genomic hybridization (array-CGH) analysis was performed to identify genes within the deleted and duplicated regions.
• The deletion on chromosome 10q involved the CALY gene.
• The duplication on chromosome 12q encompassed the PTPN11 and TBX5 genes.

Implications:

• The identified deletion of CALY and duplication of PTPN11 and TBX5 are potentially linked to the patient's observed phenotype.
• This case underscores the utility of array-CGH in pinpointing candidate genes in complex chromosomal abnormalities.
• Understanding these gene-phenotype correlations aids in diagnosing and managing rare genetic disorders.