Two cases of mirror-image eye anomalies in monozygotic twins

We report two cases of mirror image anomalies in two different pairs of monozygotic twins. In case 1, the twins exhibited mirroring of strabismus and refractive errors. Twin 1 had 35 prism diopters (PD) right intermittent exotropia at distant fixation and myopic anisometropia that was spherical 2.00 diopters more myopic in the right eye. Twin 2 had 35 PD left intermittent exotropia at distant fixation and her left eye was more myopic by - spherical 1.00 diopters. In case 2, the twins were diagnosed with infantile nystagmus with upbeat jerk. Twin 1 exhibited a habitual head turn of 30° to the left with dampening of her nystagmus in dextroversion. Twin 2 also exhibited abnormal head position, but in his case the habitual turn was 30° to the right. We believe that this is the first report describing mirror imaged intermittent exotropia with anisometropia and infantile nystagmus with opposite abnormal head positions in pairs of monozygotic twins.     

Identifying Multiple Gestation Groups Using State-Level Birth and Fetal Death Certificate Data

Purpose: Birth and fetal death certificates classify individuals as twins or higher order multiples, but do not identify multiple gestation groups. As a result, multiple gestations are consistently excluded from maternal and child health research studies despite the surge in multiple births since the early 1980s and the health risks associated with them. A standardized methodology for states to identify multiple gestation groups is proposed to allow researchers to account for multiple gestations in analyses, improve the accuracy of the incidence of multiple gestations and further knowledge of the impact of multiple gestations on birth outcomes. Methods: Using 3 years of Massachusetts birth and fetal death certificate data from 1998 to 2000 (247,959 births and 1358 fetal deaths), we assigned matching multiple gestation group numbers to records with identical combinations of mother's first name, last name, date of birth, and month of delivery. To validate our methodology, we calculated plurality and compared it to plurality reported on the existing birth and fetal death data. Results: This method correctly identified 10,765 records out of 10,795 validated multiple gestation deliveries (99.8%). Our method identified 71 additional multiple gestation deliveries, which were not identified by the birth and fetal death files. This method resulted in only 4 false positives and 51 false negatives over 3 years. Conclusions: This algorithm provides much needed information on multiple gestation groupings, and as an additional benefit, improves the identification of multiple gestation deliveries. This method has proven easy to use, employs state-level data, and offers numerous new analytic opportunities. Presentations: Maternal and Child Health Epidemiology annual meeting, Clearwater, FL, December 2002. Annual meetings of the American Public Health Association, San Francisco, CA, November 2003.     

Monozygotic twins with discordant intestinal rotation

Previous case reports have suggested a strong concordance of intestinal malrotation among identical twins. This has led to the recommendation that the asymptomatic twin undergo screening when malrotation is discovered in the identical sibling. We present a case of monozygotic twins in which one twin presented with intestinal malrotation with midgut volvulus while the other twin was found to have normal gastrointestinal anatomy.     

Surgical management to conjoined twins in Shanghai area

Conjoined twins are very rare congenital malformation. The aim of this study was to summarize our experiences of surgical separation on seven sets of conjoined twins, and improve the treatment of conjoined twins in the future. A retrospective review of surgical separation included data of prenatal diagnosis, associated malformation, timing of separation, intra- and postoperative management, and follow-up of six sets of conjoined twins at Shanghai Xin-Hua Hospital from 1980 to 2005 and one set at Shanghai Children’s Hospital in 2002. Surgical separation was performed on seven sets of conjoined twins; six sets of thoracopagus–omphalapagus (including four sets of xipho-omphalopagus) and one set of ischiopagus. All sets presented varying degrees of severity of congenital cardiac malformations. Four sets were diagnosed prenatally by ultrasonography. Two sets of conjoined twins (case 2 and case 3) required emergent separation within 7 days after birth; both members of case 2 died within 2 days post operation, one member of case 3 died during operation while the other member survived. Five sets had scheduled separation undertaken more than 30 days after birth. One member of a set (case 6B) died 13 days after operation due to severe congenital cardiovascular anomalies. All other members of conjoined twins survived. Case 6A had a severe defect of the anterior thoracic cage and prosthesis of titanium alloy scaffold filled with silicone rubber was used to repair the defects successfully. Following up from 1980 to 2005, one member of a set (case 1A) died 4 years after operation due to pneumonia. Contact was lost to the surviving member of case 3 (ischiopagus). Other survivors of the separations had normal development. (1) Timing of operation and separation plan should be given according to the circumstances and the nature of the organ shared in each individual set of twins. (2) Prosthesis of titanium alloy scaffolds filled with silicone rubber may become one of viable methods for repairing severe defects of the thoracic cage.     

Blood chimerism in monochorionic twins conceived by induced ovulation: case report

A case of monochorionic twin boys delivered at 34 weeks of gestation following induced ovulation with clomiphene is described. One twin was typed as blood group AB and the other as B. Flow cytometry showed blood group chimerism. DNA polymorphism analysis of peripheral lymphocytes and hair root cells showed that the chimerism was confined to the blood cells and they were dizygotic.     

The paradox of declining fertility but increasing twinning rates with advancing maternal age

BACKGROUND: Advancing female age is associated with declining fertility potential due to decreasing numbers and quality of oocytes but also with a distinct increase in dizygotic twinning rates, a phenomenon that has never been explained. METHOD: An analysis of follicle development was made in 959 spontaneous ovulatory cycles of 507 women. RESULTS: Multiple ovarian follicular development (>1 follicle >14 mm) and, by implication, multiple rather than single ovulations occurred in 105 women whose mean age (36.1 versus 34.6 years) and mean basal FSH concentrations (10.3 versus 7.7 IU/l) were significantly greater than those with monofollicular development (P < 0.01). The prevalence of multifollicular development increased with age. CONCLUSIONS: Dizygotic twinning must be associated with the development of >1 large follicle, which we found to be a significantly more frequent occurrence in older women. It is hypothesized that the response of pituitary release of FSH to the decreased negative feedback induced by impending ovarian failure often 'overshoots', causing multiple follicular development. In the presence of two good-quality oocytes, a twin pregnancy may result.     

Association of a balanced chromosomal translocation (4; 12)(q21.3; q15), affective disorder and autism

This case report describes a set of monozygotic twins with severe intellectual disability, autism and affective disorder with a balanced translocation between chromosomes 4 and 12. Their mother, who carries the same balanced translocation, had severe postnatal depression. The association between autism affective disorder and these chromosome break points has not been reported previously. The implications are discussed.     

Selective intrauterine growth restriction in monochorionic diamniotic twin pregnancies

Selective intrauterine growth restriction (sIUGR) affects 10–15% of all monochorionic pregnancies. Early severe forms are associated with intrauterine demise or neurological adverse outcome for both twins. The characteristics of umbilical artery (UA) Doppler in the IUGR fetus determine three clinical types: (I) normal UA Doppler and associated with good prognosis; (II) persistently absent/reverse UA end-diastolic flow and associated with early deterioration of the IUGR twin and very preterm delivery; (III) intermittently absent/reverse end-diastolic flow in the UA, and associated with unexpected fetal demise or neurological injury in one or both twins. Types II and III pose important challenges for management. Placental laser or cord occlusions do not seem to increase survival, but they might improve the outcomes of the larger twin. The use of an algorithm with severity criteria may help in counseling and planning management.