OBJECTIVE: To assess the impact of vanishing twin syndrome (VTS) on the accuracy of non-invasive prenatal testing (NIPT). METHODS: Three pregnant women who underwent NIPT testing at Guangdong Women and Children's from November 2019 to February 2020 were selected as the study subjects. The three women had either vanish twin syndrome or had undergone fetal reduction for other reasons in one of their twins, and were subsequently subject to NIPT, chromosome karyotyping, chromosome microarray analysis (CMA), and short tandem repeat (STR) analysis. This study has been approved by the Medical Ethics Committee of Guangdong Maternal and Child Health Hospital (Ethics No.: 20230132). RESULTS: Case 1 underwent selective fetal reduction at 8⁺ weeks of gestation. At 17⁺ weeks, NIPT showed a fetal DNA fraction of 2.806%, with results indicating the presence of Y chromosome and abnormal sex chromosome ratios. However, the women had subsequent uncomplicated vaginal delivery of a female infant, and no abnormality noted. Case 2 experienced spontaneous demise of one twin at 13 weeks' gestation. At 19 weeks, NIPT indicated a high risk for chromosome 21 (Z-score 4.671) in the surviving fetus, but subsequent evaluation showed no abnormality. Case 3, a dichorionic diamniotic (DCDA) twin pregnancy, underwent selective reduction at 13⁺ weeks due to fetal abnormalities in one twin. At 22⁺ weeks, NIPT for the surviving fetus indicated a high risk for chromosome 21 (Z-score 17.549), but subsequent evaluation was unremarkable. CONCLUSION In twin pregnancies, the relatively low cell-free fetal DNA (cffDNA) concentration can compromise the success rate and accuracy of NIPT compared to singleton pregnancies. Residual DNA from the demised fetus may persist for weeks following VTS or selective reduction, potentially causing false-positive NIPT results and interfering with sex chromosome prediction for the surviving fetus. Additionally, determining chorionicity is critical for reliable interpretation of NIPT results in twin pregnancies.
Adult ; Female ; Humans ; Pregnancy ; Diseases in Twins/diagnosis* ; Karyotyping ; Noninvasive Prenatal Testing/methods* ; Pregnancy, Twin ; Prenatal Diagnosis/methods*

Jr(a) is a high-frequency antigen found in all ethnic groups. However, the clinical significance of the anti-Jr(a) antibody has remained controversial. Most studies have reported mild hemolytic disease of the newborn and fetus (HDNF) in Jr(a)-positive patients. Recently, fatal cases of HDNF have also been reported. We report the first case of HDNF caused by anti-Jr(a) alloimmunization in twins in Korea. A 33-yr-old nulliparous woman with no history of transfusion or amniocentesis was admitted at the 32nd week of gestation because of vaginal bleeding caused by placenta previa. Anti-Jr(a) antibodies were detected in a routine laboratory examination. An emergency cesarean section was performed at the 34th week of gestation, and 2 premature infant twins were delivered. Laboratory examination showed positive direct antiglobulin test and Jr(a+) phenotype in the red blood cells and the presence of anti-Jr(a) antibodies in the serum in both neonates. The infants underwent phototherapy for neonatal jaundice; this was followed by conservative management. They showed no further complications and were discharged on the 19th postpartum day. Preparative management to ensure the availability of Jr(a-) blood, via autologous donation, and close fetal monitoring must be performed even in cases of first pregnancy in Jr(a-) women.
Adult ; Blood Group Antigens/immunology ; *Blood Group Incompatibility ; Diseases in Twins/diagnosis/*immunology ; Erythroblastosis, Fetal/*diagnosis/immunology ; Female ; Gestational Age ; Humans ; Infant, Newborn ; Isoantigens/immunology ; Jaundice, Neonatal/complications/immunology/therapy ; Male ; Phenotype ; Phototherapy ; Pregnancy ; Pregnancy Complications, Hematologic/diagnosis/*immunology ; Twins

Although the incidence and prevalence rates of IBD in Korea are still lower than Western populations, they have been increasing rapidly during the past decades. Crohn's disease (CD) tends to run in families because it is thought to be related to genetic susceptibility coupled with environmental factors. A large number of monozygotic and dizygotic twin pairs with inflammatory bowel disease have been reported in western countries. The population relative risk in first-degree relatives is considered to be about equal in both Koreans and westerners. To our best knowledge, there is no report in monozygotic twins with CD in Korea. This case report is the first documented occurrence of concordant CD occurring in monozygotic twins in Korea.
Adolescent ; Antimetabolites/therapeutic use ; Azathioprine/therapeutic use ; Colonoscopy ; Crohn Disease/*diagnosis/drug therapy/genetics ; Diseases in Twins/*diagnosis/drug therapy/genetics ; Humans ; Male ; Pedigree ; Tomography, X-Ray Computed ; Twins, Monozygotic/*genetics

Although the incidence and prevalence rates of IBD in Korea are still lower than Western populations, they have been increasing rapidly during the past decades. Crohn's disease (CD) tends to run in families because it is thought to be related to genetic susceptibility coupled with environmental factors. A large number of monozygotic and dizygotic twin pairs with inflammatory bowel disease have been reported in western countries. The population relative risk in first-degree relatives is considered to be about equal in both Koreans and westerners. To our best knowledge, there is no report in monozygotic twins with CD in Korea. This case report is the first documented occurrence of concordant CD occurring in monozygotic twins in Korea.
Adolescent ; Antimetabolites/therapeutic use ; Azathioprine/therapeutic use ; Colonoscopy ; Crohn Disease/*diagnosis/drug therapy/genetics ; Diseases in Twins/*diagnosis/drug therapy/genetics ; Humans ; Male ; Pedigree ; Tomography, X-Ray Computed ; Twins, Monozygotic/*genetics

Brain ; abnormalities ; Diseases in Twins ; diagnosis ; genetics ; Eye Diseases ; genetics ; Female ; Humans ; Infant, Newborn ; Muscular Dystrophies ; genetics ; Syndrome

Kaposi's varricelliform eruption is a characteristic syndrome of disseminated vesiculopustules superimposed on variable pre-existing dermatoses. Among these, atopic dermatitis is most common disease. We report two cases of Kaposi's varicelliform eruption associated with atopic dermatitis in a pair of identical twins. Diagnosis was made by the history, clinical feature, histologic examination and serologic test. These patients' condition was much improved by the treatment with antiviral agent and antibiotics.
Anti-Bacterial Agents ; Dermatitis, Atopic ; Diagnosis ; Humans ; Kaposi Varicelliform Eruption* ; Serologic Tests ; Skin Diseases ; Twins, Monozygotic*