A patient with constitutional ring 1 chromosome characterized by SNP array CGH

Area of Science:

• Genetics
• Human Molecular Genetics
• Clinical Genetics

Background:

• Ring chromosome 1 (r(1)) is a rare chromosomal abnormality associated with diverse clinical phenotypes.
• Microdeletions on chromosome 1, specifically at the 1q43q44 region, are linked to a distinct set of developmental abnormalities.
• Comparative genomic hybridization (CGH) is a molecular-cytogenetic technique used to detect chromosomal copy number variations.

Observation:

• A male patient presented with a constitutional ring 1 chromosome.
• Genetic analysis revealed a 6 Mb deletion at the 1q43q44 locus in the patient.
• The patient exhibited clinical features consistent with both ring 1 chromosome and 1q43q44 microdeletion syndrome.

Findings:

• This is the first reported case of a constitutional ring 1 chromosome characterized by comparative genomic hybridization (CGH).
• The identified 6 Mb deletion at 1q43q44 provides a molecular basis for the observed clinical phenotype.
• The overlapping features highlight the complex genotype-phenotype correlations in chromosomal abnormalities.

Implications:

• This case expands the understanding of ring 1 chromosome phenotypes and the utility of CGH in diagnosing complex chromosomal disorders.
• Characterization of this patient aids in refining the critical region for 1q43q44 microdeletion syndrome.
• Further research into genotype-phenotype correlations in ring chromosomes is warranted for improved genetic counseling and clinical management.