Hereditary 3;6 translocation : three cases of multiple malformations with partial trisomy 6p21 leads to pter

Area of Science:

• Human Genetics
• Clinical Cytogenetics
• Pediatric Genetics

Background:

• Balanced translocations can lead to unbalanced gametes, resulting in genetic disorders in offspring.
• Reciprocal translocations, like the t(3;6) observed, involve exchange of genetic material between chromosomes.
• Trisomy 6p syndrome is a rare genetic disorder associated with specific chromosomal abnormalities.

Purpose of the Study:

• To investigate the genetic basis of multiple malformations in a family with a balanced translocation t(3;6).
• To characterize the clinical features and karyotype of an infant with suspected trisomy 6p syndrome.
• To evaluate the inheritance pattern of the translocation within the family.

Main Methods:

• Karyotyping was performed on family members to identify chromosomal abnormalities.
• Clinical examination and phenotypic assessment of the proband were conducted.
• Human Leukocyte Antigen (HLA) typing was utilized to assess parental haplotype contribution.

Main Results:

• All four siblings were carriers of the balanced translocation t(3;6).
• Two siblings had children with multiple congenital malformations.
• The proband presented with a karyotype of 46,XY, t(3;6)(p26;p21)der(pat) and features consistent with trisomy 6p syndrome.
• HLA typing failed to demonstrate both paternal haplotypes in the proband.

Conclusions:

• The balanced translocation t(3;6) in this family is associated with recurrent unbalanced conceptions, leading to multiple malformations.
• The proband's phenotype is indicative of trisomy 6p syndrome, likely resulting from an unbalanced segregation of the parental translocation.
• Further investigation into the genetic mechanisms and phenotypic spectrum of this specific translocation is warranted.