Trisomy 13 (T13) and trisomy 18 (T18) are chromosomal abnormalities with high mortality rates in the first year of life. Understanding differences in long-term survival between children with full vs mosaic or partial trisomy is crucial for prognosis and health care planning. To examine the differences in 10-year survival between children with full T13 and T18 vs those with mosaic or partial trisomy. This retrospective, population-based cohort study assessed liveborn infants with T13 and T18 in the Texas Birth Defects Registry (deliveries from January 1, 1999, to December 31, 2008). Follow-up was through December 31, 2018 (the last date available at the time of analyses) to allow for 10 years of follow-up for all infants. All analyses were conducted from January 1, 2022, to December 31, 2024. Cytogenetic status (full trisomy vs mosaic or partial trisomy). The primary outcome was survival to 10 years of age, assessed using Kaplan-Meier survival estimates. The association between cytogenetic status and mortality by 10 years of age was assessed using Cox proportional hazards regression to generate hazard ratios (HRs). Population attributable fraction was calculated to determine the percentage of survival attributable to mosaic or partial trisomy status. The study cohort included 798 infants (463 female infants [58.0%]; mean [SD] maternal age, 30.9 [8.0] years) with T13 (n = 295) or T18 (n = 503). Among all cases with T13, 25 infants (8.5%; 95% CI, 5.5%-12.3%) survived to 10 years of age. Similarly, among all infants with T18, 43 (8.6%; 95% CI, 6.3%-11.3%) survived to 10 years of age. Kaplan-Meier survival estimates to 10 years of age were statistically significantly higher among children with mosaic or partial trisomy (13 [25.0%] and 14 [43.8%], respectively) compared with full trisomy (12 [4.9%] and 29 [6.6%], respectively) (both P < .001). Infants with full trisomy had statistically significantly increased 10-year mortality hazards compared with those with mosaic or partial trisomy for both T13 (HR, 2.00; 95% CI, 1.42-2.82) and T18 (HR, 3.34; 95% CI, 2.08-5.38). The results of the calculated proportion of 10-year survival due to the presence of nonfull trisomy status (population attributable fraction) was 41.7% for children with T13 and 27.9% for children with T18. The findings of this cohort study of infants with T13 and T18 support differences in long-term survival based on cytogenetic status and emphasize the need to potentially reassess the context of these conditions generally being considered incompatible with life, particularly for those with mosaic trisomies. These findings offer context surrounding treatment decisions, such as withholding interventions, for affected infants in the future.

Identification of cytogenetic abnormalities is critical for the classification and risk stratification of myelodysplastic syndromes (MDS). Optical genome mapping (OGM) is an emerging cytogenomic platform that enables high-resolution genome-wide cytogenetic analysis. We analyzed bone marrow specimens of 236 MDS patients, 149 newly diagnosed and 87 with relapsed/refractory disease, using OGM, conventional karyotyping, and next-generation sequencing analysis. OGM and karyotyping showed concordant results in 68% of cases, including 34% with normal findings by both assays. OGM provided additional information in 27% of patients. Common abnormalities detected exclusively by OGM included chromoanagenesis (n = 33), KMT2A partial tandem duplication (n = 7), and MECOM rearrangement (n = 4). These OGM findings led to disease reclassification and/or changes in risk stratification in 14 patients (9.4%) with newly diagnosed MDS. In contrast, OGM failed to detect small clones or subclones in 5% of patients, resulting in risk group changes in 2% of newly diagnosed MDS patients. We conclude that OGM enhances the cytogenetic assessment of MDS in approximately 25% of patients and leads to a change in disease classification and/or risk stratification in approximately 10% of patients. However, low sensitivity for detecting small clones or subclones remains a limitation of OGM.

Chromosome 15q duplication (Dup15q) syndrome is a rare genetic disorder that presents with a range of psychiatric and neurological symptoms. To date, no cases have been reported involving a patient with a 300 kb microduplication on chromosome 15 presenting with developmental delay, intellectual disability, attention-deficit/hyperactivity disorder (ADHD), and epilepsy. We describe a 20-year-old male diagnosed with Dup15q syndrome at the age of nine. His early development was marked by congenital strabismus, global developmental delay, and intellectual disability, which required enrollment in a special education program until age 11. He also exhibited hyperactivity, aggression, and self-injurious behavior. Since then, both his motor and cognitive functions have progressively declined. At age 14, he was diagnosed with ADHD. Treatment with atomoxetine, methylphenidate, and risperidone provided partial symptom relief. However, escitalopram triggered episodes of severe tantrums and was subsequently discontinued. From the age of 16, he began experiencing epilepsy, characterized by focal seizures, generalized tonic-clonic seizures, and absence seizures. Valproic acid (VPA) was effective in significantly reducing his seizure activity. This case highlights that Dup15q syndrome associated with a 300 kb microduplication can predominantly affect the central nervous system and may respond favorably to atomoxetine, methylphenidate, risperidone, and VPA. Dup15q syndrome should be considered in the differential diagnosis of individuals presenting with developmental delay, intellectual disability, ADHD, and epilepsy.

The 16p11.2 deletion syndrome is a clinically heterogeneous disorder, characterized by developmental delay, intellectual disability, hyperphagia, obesity, macrocephaly and psychiatric problems. Cases with 16p11.2 duplication syndrome have similar neurodevelopmental problems, but typically show a partial 'mirror phenotype' with underweight and microcephaly. Various copy number variants (CNVs) of the chromosomal 16p11.2 region have been described. Most is known about the 'typical' 16p11.2 BP4-BP5 (29.6-30.2 Mb; ~600 kb) deletions and duplications, but there are also several published cohorts with more distal 16p11.2 BP2-BP3 CNVs (28.8-29.0 Mb; ~220 kb), who exhibit clinical overlap. We assessed 100 cases with various pathogenic 16p11.2 CNVs and compared their clinical characteristics to provide more clear genotype-phenotype correlations and raise awareness of the different 16p11.2 CNVs. Neurodevelopmental and weight issues were reported in the majority of cases. Cases with distal 16p11.2 BP2-BP3 deletion showed the most severe obesity phenotype (73.7% obesity, mean BMI SDS 3.2). In addition to the more well defined typical 16p11.2 BP4-BP5 and distal 16p11.2 BP2-BP3 CNVs, we describe the clinical features of five cases with other, overlapping, 16p11.2 CNVs in more detail. Interestingly, four cases had a second genetic diagnosis and 18 cases an additional gene variant of uncertain significance, that could potentially help explain the cases' phenotypes. In conclusion, we provide an overview of our Dutch cohort of cases with various pathogenic 16p11.2 CNVs and relevant second genetic findings, that can aid in adequately recognizing, diagnosing and counseling of individuals with 16p11.2 CNVs, and describe the personalized medicine for cases with these conditions.

To explore the prenatal ultrasound phenotype and genetic basis of two fetuses with Wolf-Hirschhorn syndrome (WHS). A retrospective analysis was conducted on the ultrasound imaging data of two fetuses suspected for WHS at the Prenatal Diagnostic Center of Qingyuan People's Hospital in July 2017 and August 2019, respectively. Amniotic fluid samples of the two fetuses were subjected to chromosomal karyotyping and chromosomal microarray analysis (CMA). This study was approved by the Qingyuan People's Hospital (Ethics No. IRB-2022-064). Prenatal ultrasound examination of the two fetuses had consistently revealed WHS-associated traits including intrauterine growth restriction (IUGR), craniofacial abnormalities and cardiovascular anomalies. Karyotyping analysis suggested that both fetuses had harbored cryptic chromosomal translocations involving partial deletion of 4p. And parental verification revealed that it was de novo for fetus 1 and paternal for fetus 2. CMA has confirmed that fetus 1 had an approximately 8.7 Mb deletion at 4p16.3p16.1 and a 6.8 Mb duplication at 8p23.1p23.1, whilst fetus 2 had a 20.05 Mb deletion at 4p16.3p15.31 and a 7.66 Mb duplication at 9p24.3p24.1. The karyotype of fetus 1 was determined as 46,XN,der(4)t(4;8)(p16.1;p23.1)dn.arr[hg19]4p16.3p16.1(68345_8721580)×1, 8p23.3p23.1(158048_6933745)×3, and that of fetus 2 was determined as 46,XN,der(4)t(4;9)(p15.3;p24)pat.arr[hg19]4p16.3p15.31(68345_20116061)×1, 9p24.3p24.1(208454_7868292)×3. The 4p deletion is probably the main cause for the WHS phenotype in both fetuses. WHS should be suspected when IUGR, renal anomalies, craniofacial and cardiovascular abnormalities are detected upon prenatal ultrasound screening.