Array-CGH characterization and genotype-phenotype analysis in a patient with a ring chromosome 6

Area of Science:

• Genetics
• Cytogenetics
• Molecular Biology

Background:

• Ring chromosome 6 is a rare constitutional abnormality with variable phenotypes.
• Phenotypic severity often correlates with the extent of genetic material loss from chromosome ends.
• Previous reports primarily relied on conventional cytogenetic methods.

Observation:

• A 16-month-old Caucasian girl presented with mild motor delay, cardiac defect, and facial anomalies.
• Karyotype analysis revealed a 46,XX,r(6)(p25q27) karyotype.
• Fluorescence in situ hybridization (FISH) indicated signal absence on both arms of the ring chromosome 6.

Findings:

• Array comparative genomic hybridization (array-CGH) confirmed terminal deletions on 6p25.3 (1.3 Mb) and 6q26.27 (6.7 Mb).
• This cyto-molecular characterization provides a detailed genetic profile of the ring chromosome 6 abnormality.
• The findings were compared with existing literature on ring chromosome 6.

Implications:

• This case highlights the utility of array-CGH in precisely characterizing ring chromosome abnormalities.
• Detailed genetic information can enhance genotype-phenotype correlation studies for rare chromosomal disorders.
• Accurate characterization is crucial for understanding the clinical manifestations associated with ring chromosome 6.