Journal: Annals of Hematology
Article Title: An unusual transfusion-dependent hemoglobin H disease caused by a novel complex inverted duplication involving the α-globin regulatory elements and α-thalassemia—-SEA deletion
doi: 10.1007/s00277-025-06223-2
Figure Lengend Snippet: A Family pedigree with hematological characterization, showing that all MCS dup (αα) QZ members presented borderline MCV and MCH levels. B MLPA studies showing heterozygous MCS regulatory elements duplications in the patient (III-1) and her mother (II-2). The patient also presents the – SEA deletion in a heterozygous state. C Schematic representation of optical genome mapping (OGM) in II-2, showing the locations of MCS duplication. Horizontal boxes are used to indicate the α-globin cluster reference maps (green, hg38) aligned to the sample maps (blue). The vertical lines within boxes are labels for locations on chromosome 16. Matching labels between reference genome map and the sample (II-2) map at the normal (blue) chromosomal positions are connected by gray lines, and matching labels between reference genome map and the sample (II-2) map at the abnormal (orange) chromosomal positions are connected by blue lines. On the rearranged chromosome, the duplication sequences are in an inverted orientation. The schematic representation of the rearrangement in red box shows inverted orientation for duplicated fragments. The locations of the two breakpoints can be roughly targeted, with one in the range ofchr16:96953–130508, and the other in the range of chr16:176157–197960 (GRCh37/hg19). D Identification of the structure and the precise breakpoints of the MCS duplication. The F1 and R1 primers for the first breakpoint lead to a 2834-bp fragment and the F2 and R2 primers for the other breakpoint generate a 5506-bp fragment only in carriers and the proband. Sequencing of the two PCR products reveald the duplication is inserted between chr16:199,348 and 199,349, which includes two fragments. One is the inverted fragment from chr16:102712 to 176193 (73481 bp) and the breakpoint is joined with a 22-bp sequence. Another direct repeat sequence comes from chr16:176209 to 199348 and is inserted between 102712 and 176209 (23139 bp). The duplication is about 96,620 bp with two breakpoint junctions
Article Snippet: To investigate the genomic rearrangement, optical genome mapping (OGM) testing (Bionano Genomics, San Diego, CA, USA) was performed in the proband’s mother according to its standard operating procedures and data analysis was performed using OGM specific pipelines managed via Bionano AccessTM (v.1.7) software, which detected a 97-kb inversion with two breakpoints located within chr16:96953–130508 and chr16:176157–197960 in the proband’s mother (GRCh37/hg19) (Fig. C) (Detailed materials and methods are described in the Supplementary data) [ ].
Techniques: Sequencing
