Partial trisomy 5q and partial monosomy 5q within the same family

Area of Science:

• Human Genetics
• Medical Genetics
• Developmental Biology

Background:

• Balanced reciprocal translocations can lead to unbalanced chromosomal rearrangements in offspring.
• Reciprocal translocation t(5;10)(q31.3;q26) identified in a phenotypically normal mother.

Observation:

• Two offspring from the same mother exhibited partial trisomy 5q and partial monosomy 5q.
• The trisomic female presented with multiple congenital anomalies including craniofacial dysplasia and arhinencephalia.
• The stillborn sister with monosomy 5q displayed severe malformations, including Potter syndrome and true hermaphroditism.

Findings:

• Concurrent partial trisomy and monosomy for the 5q31-5qter segment occurred in siblings.
• Significant phenotypic differences observed between trisomy 5q and monosomy 5q in the same family.
• Monosomy 5q manifestations were more pronounced than trisomy 5q manifestations.

Implications:

• This case highlights the differential impact of deletions versus duplications on development.
• Understanding chromosomal segment effects is crucial for genetic counseling and prenatal diagnosis.
• The study reinforces the sensitivity of the 5q31-5qter region to dosage imbalances.