Molecular cytogenetic and phenotypic characterization of ring chromosome 13 in three unrelated patients.
We report on the cytogenetic and molecular investigations of constitutional de-novo ring chromosome 13s in three unrelated patients for better understanding and delineation of the phenotypic variability characterizing this genomic rearrangement. The patient's karyotypes were as follows: 46,XY,r(13)(p11q34) dn for patients 1 and 2 and 46,XY,r(13)(p11q14) dn for patient 3, as a result of the deletion in the telomeric regions of chromosome 13. The patients were, therefore, monosomic for the segment 13q34 → 13qter; in addition, for patient 3, the deletion was larger, encompassing the segment 13q14 → 13qter. Fluorescence in situ hybridization confirmed these rearrangement and array CGH technique showed the loss of at least 2.9 Mb on the short arm and 4.7 Mb on the long arm of the chromosome 13 in patient 2. Ring chromosome 13 (r(13)) is associated with several phenotypic features like intellectual disability, marked short stature, brain and heart defects, microcephaly and genital malformations in males, including undescended testes and hypospadias. However, the hearing loss and speech delay that were found in our three patients have rarely been reported with ring chromosome 13. Although little is known about its etiology, there is interesting evidence for a genetic cause for the ring chromosome 13. We thus performed a genotype-phenotype correlation analysis to ascertain the contribution of ring chromosome 13 to the clinical features of our three cases.
Department of Cytogenetics and Reproductive Biology, Farhat Hached University Teaching Hospital, Sousse, Tunisia; Common Service Units for Research in Genetics, Sousse Faculty of Medicine, Avenue Mohamed Karoui, Sousse, Tunisia.
Inesse B
IB
Abdallah-Bouhjar
Department of Cytogenetics and Reproductive Biology, Farhat Hached University Teaching Hospital, Sousse, Tunisia; Common Service Units for Research in Genetics, Sousse Faculty of Medicine, Avenue Mohamed Karoui, Sousse, Tunisia.
Soumaya
S
Mougou-Zerelli
Department of Cytogenetics and Reproductive Biology, Farhat Hached University Teaching Hospital, Sousse, Tunisia; Common Service Units for Research in Genetics, Sousse Faculty of Medicine, Avenue Mohamed Karoui, Sousse, Tunisia.
Hanene
H
Hannachi
Department of Cytogenetics and Reproductive Biology, Farhat Hached University Teaching Hospital, Sousse, Tunisia.
Abir
A
Gmidène
Department of Genetics, University Hospitals of Lyon, Lyon, France.
Audrey
A
Labalme
Department of Pediatrics, Farhat Hached University Teaching Hospital, Sousse, Tunisia.
Najla
N
Soyah
Department of Genetics, University Hospitals of Lyon, Lyon, France.
Damien
D
Sanlaville
Department of Cytogenetics and Reproductive Biology, Farhat Hached University Teaching Hospital, Sousse, Tunisia; Common Service Units for Research in Genetics, Sousse Faculty of Medicine, Avenue Mohamed Karoui, Sousse, Tunisia.
Ali
A
Saad
Department of Cytogenetics and Reproductive Biology, Farhat Hached University Teaching Hospital, Sousse, Tunisia; Common Service Units for Research in Genetics, Sousse Faculty of Medicine, Avenue Mohamed Karoui, Sousse, Tunisia.
Hatem
H
Elghezal
Array-CGH; FISH; intellectual disability; ring chromosome 13