Prenatal diagnosis of a de novo 9p terminal chromosomal deletion in a fetus with major congenital anomalies

Omphalocele and Associated Anomalies: Exploring Pulmonary Development and Genetic Correlations-A Literature Review

Omphalocele is a rare congenital abdominal wall defect, occurring in approximately 3.38 per 10,000 pregnancies. It is characterized by the herniation of abdominal organs through the base of the umbilical cord, enclosed by a peritoneal sac. While omphalocele can occur as an isolated anomaly, it is more commonly associated with congenital syndromes and structural abnormalities. Among its most significant complications, pulmonary hypoplasia (PH) and pulmonary hypertension (PPH) have been shown to negatively impact neonatal prognosis. These conditions result from impaired pulmonary vascular development, leading to respiratory distress and hypoxemia. Unlike many congenital disorders, there is no universally accepted surgical approach for omphalocele repair. The choice of surgical strategy depends on multiple factors, including the size of the abdominal wall defect, presence of herniated solid organs, associated anomalies, and severity of pulmonary complications. Notably, giant omphaloceles are frequently linked to lung hypoplasia, as reduced intra-abdominal space restricts fetal lung expansion, leading to structural lung abnormalities and increased pulmonary vascular resistance. These factors contribute to a higher risk of respiratory morbidity and mortality in affected neonates. This literature review examines the prevalence, significance, and clinical implications of the association between omphalocele and pulmonary abnormalities. Through a systematic analysis of published studies, we evaluated 157 full-text articles along with available titles and abstracts. Our findings indicate that infants with omphalocele often exhibit respiratory complications detectable prenatally and at birth. Severe respiratory insufficiency, particularly due to pulmonary hypoplasia and pulmonary hypertension, significantly increases neonatal morbidity and mortality. While surgical correction may initially exacerbate respiratory challenges, most patients demonstrate short-term recovery with appropriate multidisciplinary management. This review highlights the importance of early diagnosis, comprehensive prenatal assessment, and tailored postnatal management to improve outcomes in newborns with omphalocele and associated pulmonary complications. Further research is needed to establish standardized treatment protocols and optimize long-term respiratory outcomes in these patients.

Using a new analytic approach for genotyping and phenotyping chromosome 9p deletion syndrome

Using a new analytic method ("unique non-overlapping region" (UNOR) analysis), we characterized the genotypes and phenotypes of a large cohort of individuals diagnosed with chromosome 9p deletion syndrome (9PMS) and defined critical genomic regions. We extracted phenotypic information from 48 individuals with 9PMS from medical records and used a guided interview with caregivers to clarify ambiguities. Using high-resolution whole-genome sequencing for breakpoint definition, we aligned deletions and drew virtual breakpoints to obtain UNORs associated with phenotypic characteristics. We next extracted genotype and phenotype data for 57 individuals identified from a systematic review of the 9PMS literature and analyzed these as above. Common phenotypic features included developmental delay/intellectual disability, dysmorphic features, hypotonia, genital defects in XY individuals, psychiatric diagnoses, chronic constipation, atopic disease, vision problems, autism spectrum disorder, gastroesophageal reflux disease, trigonocephaly, congenital heart disease, and neonatal hypoglycemia. Our approach confirmed previous literature reports of an association of FREM1 with trigonocephaly and suggested a possible modifier element for this phenotype. In conclusion, the UNOR approach delineated phenotypic characteristics for 9PMS and confirmed the critical role of FREM1 and a possible long-distance regulatory element in pathogenesis of trigonocephaly that will need to be replicated in future studies.

[Clinical and cytogenetic study in a child with de novo chromosome 9 abnormality]

This study aimed to analyze the clinical phenotype of chromosome 9p deletion or duplication and its relationship with karyotype. A patient, female, aged 6 months, visited the hospital due to motor developmental delay. Karyotype analysis identified abnormalities of chromosome 9 short arm, and high-throughput sequencing found 9p24.3-9p23 deletion and 9p23-9p13.1 duplication. Her parents had a normal karyotype. Karyotype analysis combined with high-throughput sequencing is of great significance for improving the efficiency of etiological diagnosis in children with motor developmental delay or multiple congenital deformities and mental retardation.

Clinical findings and molecular cytogenetic study of de novo pure chromosome 9p deletion: Pre- and postnatal diagnosis

OBJECTIVE

The aim of this report is to describe the phenotype-genotype correlation of chromosome 9p deletion syndrome cases, particularly the prenatal cases.

MATERIALS AND METHODS

A 30-year-old woman was referred to a hospital at 19⁺¹ weeks of gestation because of omphalocele detected in the fetus. The conventional karyotyping analysis and array comparative genomic hybridization (aCGH) were utilized for the prenatal diagnosis and genetic counseling in the fetus. The prenatal abnormality and cytogenetic findings in the fetus were compared with other patients with 9p deletion.

RESULTS

Karyotype analysis of the fetus cell showed a karyotype of 46,XX,del(9)(p22). aCGH analysis detected a deletion as arr[hg19] 9p24.2p22.2(226,7812-1,7466,907)×1. Individuals with 9p deletions tend to have features with widely variable expressivity. The common clinical manifestations of the 9p deletion include development delay, learning difficulties, hypotonia and trigonocephaly.

CONCLUSION

Phenotypes of 9p deletion cases are broadly in line. The prenatal diagnosis of the omphalocele provides evidence for a correlation with distal 9q deletion.

Prenatal diagnosis and molecular cytogenetic characterization of a de novo unbalanced reciprocal translocation of der(9)t(9;14)(p24.2;q32.11) associated with 9p terminal deletion and 14q distal duplication

OBJECTIVE

We present molecular cytogenetic characterization of a prenatally detected derivative chromosome 9 [der(9)] of unknown origin.

CASE REPORT

A 35-year-old woman underwent amniocentesis at 18 weeks of gestation because of advanced maternal age, which revealed a der(9) chromosome of unknown origin. The parental karyotypes were normal. Array comparative genomic hybridization (aCGH) analysis revealed a 2.593 Mb deletion of 9p24.3-p24.2 encompassing DOCK8, KANK1, DMRT1, and VLDLR and a 16.65 Mb duplication of 14q32.11-q32.33 encompassing DLK1, RTL1, MEG3, RTL1as, and MEG8. Quantitative fluorescent polymerase chain reaction (QF-PCR) analysis using D9S937 (9p24.2) and D14S605 (14q32.2) showed a paternal origin of 9p24.2 deletion and a paternal origin of 14q32.2 duplication consistent with a paternal origin of the de novo aberrant chromosome of der(9)t(9p;14q). The fetal karyotype was 46,XX,der(9)t(9;14) (p24.2;q32.11). Metaphase fluorescence in situ hybridization (FISH) analysis using RP11-57K23 (14q32.33), RP11-31F19 (9p24.3), RP11-30O14 (9p21.1), and RP11-1105I14 (14q11.2) confirmed an unbalanced reciprocal translocation of der(9)t(9p;14q). We discuss 9p deletion syndrome and 14q duplication syndrome in this case.

CONCLUSION

Molecular cytogenetic techniques such as aCGH, FISH, and QF-PCR are useful in the determination of the origin and nature of a prenatally detected de novo derivative chromosome of unknown origin.