BACKGROUND: Trisomy 20p is a rare genetic condition caused by a duplication of the short arm of chromosome 20.
METHODS: We employed clinical observation and molecular genetic testing (SNP microarray), to study identical twin males with an unknown dysmorphic syndrome. We conducted a literature review of trisomy 20p and collated the clinical and molecular genetic findings on 20 affected subjects reported since 2000.
RESULTS: Identical twin males, whose prenatal course was complicated by a twin-to-twin transfusion, manifested profound language and neurocognitive delays as well as distinctive facial dysmorphisms when evaluated at 2 years of age. SNP microarray identified identical duplications of 20p13 with no other chromosomal aberrations. A literature survey of 20p trisomy syndrome identified 20 other examples of this condition reported since 2000, which we collated with 33 summarized by Sidwell et al. (2000). Within the combined total of 55 affected individuals, we found a distinctive clinical phenotype that provides insight on the effects of abnormal dosage of genes in 20p13. These loci include FAM110A (OMIM 611393), ANGPT4 (OMIM 603705), RSPO4 (OMIM 610573), PSMF1 (OMIM 617858), SNPH (OMIM 604942), SDCBP2 (OMIM 617358), FKBP1A (OMIM 186945), TMEM74B, C20orf202, and RAD21L1 (OMIM 619533). Gene profiling highlighted that syntaphilin (SNPH) is highly expressed in mammalian brain, where it is considered critical for mitochondrial transport in neuronal axons, and to directly influence axonal morphogenesis and function.
CONCLUSIONS: We propose that abnormal activity of syntaphilin engendered by the trisomy is primarily responsible for the language, neurocognitive, and gross motor delays reported in individuals with 20p trisomy. Additional studies, for example, characterization of cerebral organoids generated from affected patients may help to better understand this condition, and potentially suggest rational remedies to improve the lives of affected individuals and their families.

暂无摘要。

BACKGROUND: The etiology of osteochondrosis dissecans (OCD), a chondropathy associated with detachment of the subchondral bone and the overlaying cartilage, is not yet fully understood. While repetitive physical exercise-related stress is usually assumed to be the main risk factor for the occurrence of OCD, genetic predisposition could have an underestimated influence on the development of the disease.
METHODS: We report a case of monozygotic twins with almost identical stages of bilateral osteochondrosis dissecans of the knee joint. In both patients, initially, a unilateral lesion occurred; despite restricted physical exercise, in the further course of the disease a lesion also developed on the contralateral side. While the lesion found most recently demonstrated an ongoing healing process at a 6-month follow-up, the other three lesions showed a natural course of healing under conservative treatment with significant clinical as well as radiological improvements after one year and complete consolidation in magnetic resonance imaging (MRI) after 2 years.
CONCLUSIONS: There could be a genetic component to the development of OCD, although this has not yet been proven. Based on a two-year MRI follow-up, we were able to show the self-limiting characteristics of juvenile osteochondrosis dissecans.

因诉讼需要，某法院委托本鉴定所对吴某（男，33岁）和双胞胎男孩（吴某郎与吴某易，均为3岁）进行有无亲生血缘关系的鉴定。据法院提供的两子户籍证明及出生证明信息，可明确两者为同母双胞胎。按《亲权鉴定技术规范》（GB/T 37223—2018）要求对吴某、吴某郎与吴某易分别采集血样。.

Median arcuate ligament syndrome (MALS) is a rare clinical entity arising from the extrinsic compression of the coeliac axis by the median arcuate ligament. In this report, we detail a unique presentation involving monozygotic twins, both of whom demonstrated anatomical extrinsic compression of the coeliac axis by the median arcuate ligament. Intriguingly, only one twin manifested clinical symptoms consistent with MALS, despite comparable anatomical compression of the coeliac axis observed in both. This case highlights the potential interplay of a genetic or anatomical predisposition to coeliac axis compression and secondary, possibly environmental, factors that lead to the development of clinical symptoms. In this report, we explore various determinants potentially influencing symptomatology in MALS and advocate for the publication of similar case studies to further elucidate this rare condition.

BACKGROUND: Retinoblastoma (rb) is the most frequent intraocular tumor, accounting for 3% of all childhood cancers. Heritable rb survivors are germline carriers for an RB1 mutation and have a lifelong risk to develop non-ocular second primary tumors (SPTs) involving multiple other organs like the bones, soft tissues, or skin. These SPTs usually become manifest several years succeeding the diagnosis of rb. In our instance, however, a non-ocular SPT presented prior to the diagnosis of heritable rb.
METHODS: We report a rare case of a monozygotic twin who presented with primary rhabdomyosarcoma (RMS) preceding the manifestation of heritable rb. The rb was diagnosed when the child developed strabismus while already on therapy for the RMS. The child underwent therapy for both as per defined treatment protocols. The rb regressed well on treatment, but the RMS relapsed and the child developed multiple refractory metastatic foci and succumbed to his disease.
CONCLUSIONS: Non-ocular SPTs like sarcomas are usually known to manifest in heritable rb survivors with a lag of two to three decades (earlier if exposure to radiation is present) from the presentation of the rb. However, in our case, this seemed to be reversed with the RMS being manifest at an unusual early age and the rb being diagnosed at a later point in time.

Multiple pregnancies are associated with significant maternal, fetal, and neonatal risks, including prematurity, low birth weight, pre-eclampsia, anemia, postpartum hemorrhage, intrauterine growth restriction, neonatal morbidity, and increased neonatal and infant mortality rates. Assisted reproductive technology (ART) treatments should prioritize efforts to reduce such events, resisting patient demand for the transfer of multiple embryos at each transfer to increase success rates. Extended culture, embryo selection, and single blastocyst transfer can mitigate the risk of high-order multiple pregnancies. Intriguingly, elective single-embryo transfer (eSET) greatly reduces, but does not completely eliminate, the likelihood of multiple gestations. The occurrence of monozygotic twinning (MZT) gives rise to identical twins. It is more prevalent in women undergoing in vitro fertilization (IVF) compared with natural conception. In fact, the reported risks of monozygotic twinning in IVF and natural conception are 1.7 and 0.4%, respectively. The factors suspected to increase the risk of MZT in IVF are multiple embryo transfer, micromanipulation, and extended in vitro culture. Determining chorionicity and amnionicity is crucial in the assessment of multiple pregnancies during the first-trimester ultrasound examination. Dichorionic twins result from embryo splitting within 3 days after fertilization, while monochorionic twins occur when the splitting takes place between 4 and 8 days after fertilization. These timings are suggested by observations carried out in natural pregnancies. In ART, there is evidence of dichorionic twins derived from single embryo transfer (SET). Here, we report a case of dichorionic diamniotic triplets after a single blastocyst transfer occurred in our center. To our knowledge, this is the first case documented so far.

We report a case of monozygotic twin sisters with hereditary spastic paraplegia type 4 (SPG4) and epilepsy, only one of whom had a diagnosis of narcolepsy type 1 (NT1). The older sister with NT1 exhibited excessive daytime sleepiness, cataplexy, sleep-onset rapid eye movement period in the multiple sleep latency test, and decreased orexin levels in cerebrospinal fluid. Both sisters had HLA-DRB1*15:01-DQB1*06:02 and were further identified to have a novel missense mutation (c.1156A > C, p.Asn386His) in the coding exon of the spastin (SPAST) gene. The novel missense mutation might be involved in the development of epilepsy. This case is characterised by a combined diagnosis of SPG4 and epilepsy, and it is the first report of NT1 combined with epilepsy and genetically confirmed SPG4. The fact that only one of the twins has NT1 suggests that acquired and environmental factors are important in the pathogenesis of NT1.

The authors present the cases of monozygotic male twins with right-sided Legg-Calvé-Perthes disease (LCPD) with different formation of the lumbosacral junction. This is likely the fi rst description of a lumbosacral junction formation disorder associated with identical twins who were both treated for LCPD as children. The disease began at 6 and 9 years of age and during treatment as well as in adulthood signifi cantly different bone formation of the lumbosacral transitional vertebra, was observed in both brothers. Twin A has a unilateral right-sided fusion of the enlarged L5 transverse process with the ipsilateral sacral ala, twin B has a complete sacralization of the fi fth lumbar vertebra. The LCPD treatment outcomes in the twins were consistent with the results from large studies, i.e., age at the time of LCPD onset is the main factor infl uencing the prognosis, however the morphological difference in the transitional vertebrae in these monozygotic twins was signifi cantly. Key words: lumbosacral transitional vertebra, lumbosacral junction formation, sacralization of lumbar vertebra, megatransverse of vertebra L5.

BACKGROUND: Thrombosis of one of the umbilical arteries is a rare complication of pregnancy and is associated with adverse pregnancy outcomes, including stillbirth and intrauterine growth restriction. Although extremely rare, umbilical artery thrombosis (UAT) in monochorionic diamniotic twins is difficult to diagnose prenatally and manage. UAT has a poor prognosis and is associated with an increased perinatal mortality rate. In most previous cases, emergency cesarean section was performed or intrauterine fetal death occurred at the time of UAT diagnosis.
METHODS: Herein, we report an extremely rare case of sequential UAT in monochorionic diamniotic twins diagnosed via ultrasound at 29+ 5 weeks of gestation in a 34-year-old woman. Following expectant management with intensive monitoring for 16 days, two healthy infants were delivered through an emergency cesarean section. UAT in both fetuses was confirmed by pathological examination. The mother and twins described in this case underwent long-term follow-up and are currently in good health without any complications.
CONCLUSIONS: Based on our experience, we suggest that expectant management should be undertaken as long as the mother and infants are stable on ultrasonographic scans and are closely monitored. When UAT is suspected, we believe that the best delivery time should be determined by considering complaints of unusual fetal movements, non-stress test evidence, gestational age, amniotic fluid volume, and blood flow in the umbilical artery, middle cerebral artery, and ductus venosus. Obstetricians should ensure that the patients and their families are clearly informed about all potential risks of expectant management for UAT.