To inform clinicians of the first known case of a live born diagnosed with syndromic partial trisomy 15 and maternal uniparental disomy 15 resulting from a mosaic embryo transfer (MET). We believe that this case will highlight the need for standardized practice guidelines to address the potential risk of MET and the importance of prenatal follow-up after a pregnancy is achieved from a MET. Case report. In vitro fertilization with preimplantation genetic testing for aneuploidy (PGT-A) and MET was completed at a fertility clinic in Canada. Postnatal testing and diagnosis were performed at the Medical Genetics Department of a hospital in Canada. A newborn male with a diagnosis of partial trisomy 15 and uniparental disomy (UPD) 15. Mosaic embryo transfer after PGT-A was performed. Diagnostic testing performed after birth included a karyotype, fluorescence in situ hybridization analysis, chromosomal microarray, and microsatellite UPD testing. Confirmed nonmosaic partial aneuploidy of trisomy 15 and UPD15 in a symptomatic newborn conceived from MET. Singleton pregnancy was achieved after a double embryo transfer involving 1 embryo diagnosed by PGT-A with high-level mosaic trisomy 15 and high-level mosaic deletion on chromosome 20 (mos(del(20)(q11.23-qter)). Routine prenatal screening and detailed fetal ultrasound did not identify any concerns. Postnatal genetic investigations, triggered by feeding difficulties in the newborn period, diagnosed the proband with maternal UPD15 and a supernumerary marker chromosome composed of 2 noncontiguous regions of chromosome 15. This karyotype is likely resulting from incomplete trisomy rescue occurring on the paternal chromosome 15. This case highlights the need for better guidelines and management of pregnancies achieved after MET.

Copy number variations (CNVs) involving the JAG1 gene are rare and infrequently reported in the scientific literature. Recently, a generally healthy young patient presenting with a history of behavioural concerns was referred to us. Herein, we discuss the patient, a 7-year-old female possessing a 0.797 Mb microduplication within the short arm of chromosome 20 at band 12.2. The patient generates considerable curiosity due to the rarity of her case, which includes a de novo partial duplication involving the JAG1 gene. The patient exhibits a wide range of symptoms including facial dysmorphism (dolichocephaly, round face, tented philtrum, anteverted nares, and micrognathia), clinodactyly, and an inborn congenital heart defect. She presented with behavioural concerns including ADHD-I, SPD, motor clumsiness, and poor self-regulation. Deletions in JAG1 are often linked to Alagille Syndrome; however, complete duplications have not been specifically identified as disease-causing. JAG1 mutations are reported alongside various clinical features including facial dysmorphology, heart defects, vertebral abnormalities, and ocular dysmorphic features (strabismus, epicanthal folds, and slanted palpebral fissures). This particular microduplication is rare, and thus, limited data exist regarding its significance. To our knowledge, most reported duplications are larger than 0.797 Mb. This may define a critical region causing phenotypical changes in some patient cases.

Two chromosome anomalies are frequent in the bone marrow (BM) of patients with Shwachman-Diamond syndrome (SDS): an isochromosome of the long arm of chromosome 7, i(7)(q10), and an interstitial deletion of the long arm of chromosome 20, del(20)(q). These anomalies are associated with a lower risk of developing myelodysplasia (MDS) and/or acute myeloid leukemia. The chromosome anomalies may be due to an SDS-specific karyotype instability, reflected also by anomalies that are not clonal, but found in single cells in the BM or in peripheral blood (PB). Starting in 1999, we have monitored the cytogenetic picture of a cohort of 91 Italian patients with SDS by all suitable cytogenetic and molecular methods. Here, we report clonal chromosome anomalies that are different from the aforementioned, as well as changes found in single cells in BM/PB of the same patients. Some of the newly recognized clonal anomalies in BM reported here are recurrent, especially unbalanced structural anomalies of chromosome 7, a further complex rearrangement of the del(20)(q) with duplicated and deleted portions, and an unbalanced translocation t(3;6), with partial trisomy of the long arm of chromosome 3 and partial monosomy of the long arm of chromosome 6. Firm conclusions on the possible prognostic relevance of these anomalies would require further study with larger patient cohorts, but our data are sufficient to suggest that these patients necessitate more frequent cytogenetic monitoring. The results on anomalies found in single cells confirm the presence of an SDS-specific karyotype instability.