Anibal GaviriaCADENA ULLAURI, SANTIAGO ANDRESANTIAGO ANDRECADENA ULLAURIFrancisco CevallosGUEVARA RAMIREZ, ALEXANDRA PATRICIAALEXANDRA PATRICIAGUEVARA RAMIREZTAMAYO TRUJILLO, VICTOR RAFAELVICTOR RAFAELTAMAYO TRUJILLORUIZ POZO, VIVIANA ALEJANDRAVIVIANA ALEJANDRARUIZ POZOPAZ CRUZ, ELUIS ANDRESELUIS ANDRESPAZ CRUZZAMBRANO ESPINOSA, ANA KARINAANA KARINAZAMBRANO ESPINOSA2024-11-062024-11-062022-09-0510.1186/s13039-022-00618-whttps://cris.ute.edu.ec/handle/123456789/459<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>Hemophilia A is considered one of the most common severe hereditary disorders. It is an X-linked recessive disease caused by a deficiency or lack of function of the blood clotting factor VIII. Klinefelter syndrome is a genetic disorder that affects male individuals due to one or more extra X chromosomes, present in all cells or with mosaicism. The aneuploidy is due to either mitotic or meiotic chromosome non-disjunction. Chromosomal translocations are a group of genome abnormalities in which a region or regions of a chromosome break and are transferred to a nonhomologous chromosome or a new location in the same chromosome.</jats:p> </jats:sec><jats:sec> <jats:title>Case presentation</jats:title> <jats:p>Our subject was born in Ecuador at 36 weeks of gestation by vaginal delivery. At 3 months old, the Factor VIII activity measure showed a 23.7% activity indicating a diagnosis of mild hemophilia A. At 1 year old, the karyotype showed an extra X chromosome, consistent with a diagnosis of Klinefelter syndrome, and a translocation between the long arms of chromosomes 1 and 19, at positions q25 and q13, respectively.</jats:p> </jats:sec><jats:sec> <jats:title>Conclusions</jats:title> <jats:p>Klinefelter syndrome and hemophilia are a rare combination. In the present case report, the subject presents both, meaning that he has inherited one X chromosome from the father and one X chromosome from the mother. Since the father has severe hemophilia A; and the subject presents a below 40% Factor VIII activity, a skewed X inactivation is suggested. Additionally, the proband presents a translocation with the karyotype 47,XXY,t(1;19)(q25;q13). No similar report with phenotypic consequences of the translocation was found. The present report highlights the importance of a correct diagnosis, based not only on the clinical manifestations of a disease but also on its genetic aspects, identifying the value of integrated diagnostics. The subject presents three different genetic alterations, Klinefelter syndrome, hemophilia A, and a 1;19 chromosomal translocation.</jats:p> </jats:sec>text::journal::journal article