Central conducting lymphatic anomaly (CCLA) due to congenital maldevelopment of the lymphatics can result in debilitating and life-threatening disease with limited treatment options. We identified 4 individuals with CCLA, lymphedema, and microcystic lymphatic malformation due to pathogenic, mosaic variants in KRAS . To determine the functional impact of these variants and identify a targeted therapy for these individuals, we used primary human dermal lymphatic endothelial cells (HDLECs) and zebrafish larvae to model the lymphatic dysplasia. Expression of the p.Gly12Asp and p.Gly13Asp variants in HDLECs in a 2‑dimensional (2D) model and 3D organoid model led to increased ERK phosphorylation, demonstrating these variants activate the RAS/MAPK pathway. Expression of activating KRAS variants in the venous and lymphatic endothelium in zebrafish resulted in lymphatic dysplasia and edema similar to the individuals in the study. Treatment with MEK inhibition significantly reduced the phenotypes in both the organoid and the zebrafish model systems. In conclusion, we present the molecular characterization of the observed lymphatic anomalies due to pathogenic, somatic, activating KRAS variants in humans. Our preclinical studies suggest that MEK inhibition should be studied in future clinical trials for CCLA due to activating KRAS pathogenic variants.

Diagnosis of a chromosome 22q11.2 microdeletion and its associated deletion syndrome (22q11.2DS) is optimally made early. We reviewed the available literature to provide contemporary guidance and recommendations related to the prenatal period. Indications for prenatal diagnostic testing include a parent or child with the 22q11.2 microdeletion or suggestive prenatal screening results. Definitive diagnosis by genetic testing of chorionic villi or amniocytes using a chromosomal microarray will detect clinically relevant microdeletions. Screening options include noninvasive prenatal screening (NIPS) and imaging. The potential benefits and limitations of each screening method should be clearly conveyed. NIPS, a genetic option available from 10 weeks gestational age, has a 70–83% detection rate and a 40–50% PPV for most associated 22q11.2 microdeletions. Prenatal imaging, usually by ultrasound, can detect several physical features associated with 22q11.2DS. Findings vary, related to detection methods, gestational age, and relative specificity. Conotruncal cardiac anomalies are more strongly associated than skeletal, urinary tract, or other congenital anomalies such as thymic hypoplasia or cavum septi pellucidi dilatation. Among others, intrauterine growth restriction and polyhydramnios are additional associated, prenatally detectable signs. Preconception genetic counselling should be offered to males and females with 22q11.2DS, as there is a 50% risk of transmission in each pregnancy. A previous history of a de novo 22q11.2 microdeletion conveys a low risk of recurrence. Prenatal genetic counselling includes an offer of screening or diagnostic testing and discussion of results. The goal is to facilitate optimal perinatal care.

Interruption of the aortic arch (IAA) is a rare but life-threatening congenital heart defect if not corrected in the neonatal period. IAA type B is highly correlated with 22q11.2 deletion syndrome (22q11.2DS); approximately 50% of patients with IAA type B also have 22q11.2DS (Peyvandi et al.; Goldmuntz et al.). Early identification and repair of IAA can prevent severe morbidity and death. However, IAA is challenging to identify prenatally, or even in the neonatal period. In this study, we examined infants with IAA, diagnosed during pregnancy and prior to discharge (PPTD) from the birth hospital vs. those diagnosed following discharge (FD) from the newborn nursery. Our goals were to determine: (1) if early diagnosis improved outcomes; and (2) if patients with IAA and without 22q11.2DS had similar outcomes. In total, 135 patients with a diagnosis of 22q11.2DS and IAA were ascertained through the 22q and You Center at the Children’s Hospital of Philadelphia (CHOP). The examined outcomes included: timing of diagnosis; age at diagnosis (days); hospital length of stay (LOS); duration of intensive care unit (ICU) stay; mechanical ventilation (days); duration of inotrope administration (days); year of surgical intervention; birth hospital trauma level; and overall morbidity. These outcomes were then compared with 40 CHOP patients with IAA but without 22q11.2DS. The results revealed that the PPTD neonates had fewer days of intubation, inotrope administration, and hospital LOS when compared to the FD group. The outcomes between deleted and non-deleted individuals with IAA differed significantly, in terms of the LOS (40 vs. 39 days) and time in ICU (28 vs. 24 days), respectively. These results support the early detection of 22q11.2DS via prenatal screening/diagnostics/newborn screening, as IAA can evade routine prenatal ultrasound and postnatal pulse oximetry. However, as previously reported in patients with 22q11.2DS and congenital heart disease (CHD), patients with 22q11.2DS tend to fare poorer compared to non-deleted neonates with IAA.

Agenesis of the corpus callosum (ACC) has a wide spectrum of anatomic manifestations associated with incompletely understood clinical variability. In this retrospective cohort study, 161 children with ACC were classified into complete ACC and partial ACC. Partial and complete ACC diagnoses were confirmed by postnatal magnetic resonance imaging (MRI) and further classified as isolated or complex (associated with other brain abnormalities or genetic diagnoses). Clinical characteristics, clinical outcomes, and co-occurring genetic variations were collected by chart review. Median age at last neurologic evaluation for the complete and partial ACC cohorts were 2.8 years and 2.3 years, respectively; thus, an average of 2-3 years of follow-up data were analyzed per patient. Results showed that children with complete and partial ACC had similar birth characteristics. Children with complete ACC were more frequently diagnosed prenatally; additionally, complete ACC patients had lower rates of cerebral palsy. When comparing complex complete ACC and complex partial ACC to isolated complete ACC and isolated partial ACC, respectively, the complex subcohorts had a higher level of motor delay, assistive device use, cerebral palsy, ventriculoperitoneal shunt placement, epilepsy, language delay, and cognitive delay than the isolated subcohorts. About 50% of children had genetic variants associated with neurodevelopmental disorders in this cohort. Additionally, >50% of our patients with motor and nonmotor developmental delays, as well as >60% of patients that required assistive devices and had cerebral palsy, were also found to have genetic anomalies. Although research describing ACC and its outcomes is expanding, there is still a need for large cohort studies with robust follow-up data to help further understand the disease.

Purpose: Genetic counselors (GCs) increasingly play key roles in advancing genomic medicine through innovative research. Here, we examine one large cohort of GCs’ evolving contributions to the literature, with the goal of facilitating worldwide professional development for GCs through scholarly activities. Methods: Publications were cataloged by members of the Section of Genetic Counseling (Section), established at the Children’s Hospital of Philadelphia and the University of Pennsylvania in 2014, including publication year, journal, impact factor, and author position. Data were organized using the “My Bibliography” tool on the National Center for Biotechnology Information website and a Research Electronic Data Capture database created to initially collect manuscripts published through 30 June 2020. A subsequent survey captured publications through 5 February 2024. Results: An amount of 52 of 120 (43%) GCs shared their curriculum vitae/papers. 992 unique publications were identified from 1986 to 2024. Since 2013, no less than 32 papers were published annually by Section members and no less than 10 GCs contributed to publications yearly. Impact factors typically averaged >5.0 per year. Areas of foci diversified considerably since 2015. Conclusions: Here, we establish that GCs indeed contribute to scholarly work as evidenced by the number of publications alone. The establishment of an academic home may have contributed, given publications increased concurrent to launching the Section, providing a model for organizing GCs at institutions nationally and internationally. Highlighting such achievements will foster the expansion of GC roles in the era of precision genomic medicine and therapy. Considering ways to support GCs towards expanding these activities is equally important.

Variants in COL4A1 and COL4A2 are associated with a multisystem disorder characterized by prominent neurologic involvement that includes intracranial hemorrhages, white matter injury, neurodevelopmental impairment, and epilepsy. The phenotypic spectrum, however, is broad, and disease subgroups have not been robustly identified. The objective of this study was to distinguish pediatric subgroups based on age at symptom onset. This was a retrospective cohort study of pediatric patients with variants in COL4A1 or COL4A2 seen at a single center between January 2008 and October 2024. Patients were included if they had likely pathogenic/pathogenic variants or variants of uncertain significance with consistent clinical phenotype and were followed for ≥6 months. Medical records, laboratory data, and neuroimaging were reviewed. Patients were stratified by age at symptom onset into perinatal, early childhood, and late childhood onset (up to 28 days, up to 4 years, and up to 18 years, respectively). Of the 44 patients meeting inclusion criteria, 33 had variants in COL4A1, 10 in COL4A2, and 1 in both. Neurologic features, such as global developmental delay, cerebral palsy, and epilepsy, were common in perinatal and early childhood cases. In COL4A1-related disease, such neurologic features were present in 14/17 and 8/9 cases, respectively. These features similarly occurred in all patients with perinatal (n = 3) and early childhood (n = 6) onset of COL4A2-related disease. Conversely, these manifestations were less common in late childhood presentations of either disorder (n = 6 total), occurring in 33% of patients. Extracentral nervous system manifestations, particularly ocular abnormalities and renal disease, were predominantly seen in COL4A1-related disease. Neuroimaging in perinatal and early childhood presentations frequently demonstrated periventricular hemorrhagic infarction (20/26 and 6/9 of COL4A1 and COL4A2 patients). Isolated leukoencephalopathy was universally present in late childhood onset patients. The pediatric phenotype of COL4A1/2-related disorder varies by age at disease onset. Perinatal and early childhood presentations (≤4 years) have a prominent neurologic phenotype with severe developmental delays, cerebral palsy, and epilepsy, correlating on imaging with sequelae from brain injury during prenatal brain development. Late childhood presentations (>4 years) have a milder phenotype, typically with isolated leukoencephalopathy on imaging.