Prader-Willi syndrome and chromosomal mosaicism 46,XY/47,XY,+mar in two cases

Area of Science:

• Genetics
• Developmental Biology
• Clinical Medicine

Background:

• Prader-Willi syndrome is a complex genetic disorder characterized by developmental abnormalities.
• Chromosomal abnormalities are observed in a subset of Prader-Willi syndrome patients.
• Understanding the origin of these aberrations is crucial for genetic counseling.

Observation:

• This report details two cases of Prader-Willi syndrome exhibiting a specific chromosomal abnormality: 46,XY/47,XY,+mar.
• The identified abnormality involves a supernumerary marker chromosome in a male karyotype.
• This karyotype is less common among Prader-Willi syndrome patients with known chromosomal variations.

Findings:

• The majority of Prader-Willi syndrome cases with chromosomal anomalies involve 15/15 translocations or mosaicism.
• The 46,XY/47,XY,+mar aberration in these cases is presumed to arise post-fertilization.
• A potential correlation between advanced parental age and the occurrence of chromosomal abnormalities in Prader-Willi syndrome is suggested.

Implications:

• These findings contribute to the understanding of the diverse genetic landscape of Prader-Willi syndrome.
• Further research into the etiology of rare chromosomal aberrations in Prader-Willi syndrome is warranted.
• Investigating the parental age effect may refine risk assessment and genetic counseling for affected families.