Marker chromosomes: cytogenetic characterization and implications for prenatal diagnosis

Area of Science:

• Cytogenetics
• Human Genetics
• Prenatal Diagnostics

Background:

• Satellited marker chromosomes are rare genetic findings.
• Their clinical significance, especially in prenatal diagnosis, can be challenging to ascertain.
• Accurate characterization is crucial for genetic counseling.

Observation:

• Four unrelated individuals with satellited marker chromosomes were identified.
• One case originated from amniotic fluid cell cultures during prenatal diagnosis.
• Chromosome-banding techniques were employed for detailed analysis.

Findings:

• Precise identification of satellited marker chromosomes originating from chromosome 15 was achieved.
• A supernumerary bisatellited derivative (der(15)) marker chromosome was characterized.
• This specific marker, containing the proximal long arm of chromosome 15, is linked to developmental and intellectual disabilities.

Implications:

• Chromosome-banding techniques are vital for characterizing complex chromosomal abnormalities.
• Accurate identification of marker chromosomes improves genetic counseling accuracy.
• Understanding the implications of der(15) markers aids in predicting developmental outcomes.