8p 11 Microduplication Is Associated with Neonatal Stridor

Chromosome 8p Syndromes Clinical Presentation and Management Guidelines

Rearrangements of the p-arm of Chromosome 8 can result in a spectrum of neurodevelopmental challenges, along with increased risk of epilepsy, structural brain and cardiac malformations, persisting developmental delays, and other health challenges. The majority of patients reported on in this sample are characterized by an inverted-duplication deletion rearrangement, but deletions, duplications, and mosaic ring changes in 8p result in similar phenotype. In this report, we add to the phenotypic and functional description of these patients according to their specific chromosomal rearrangement, share neuro-psychometric values, and propose surveillance care guidelines for caregivers and medical providers of patients with Chromosome 8p Syndromes. Observations from clinical experience with 24 patients seen at our 8p-dedicated Multi-Disciplinary Neurogenetics program are shared.

Prenatal diagnosis of 18p deletion and 8p trisomy syndrome: literature review and report of a novel case

18p deletion syndrome constitutes one of the most frequent autosomal terminal deletion syndromes, affecting one in 50,000 live births. The syndrome has un-specific clinical features which vary significantly between patients and may overlap with other genetic conditions. Its prenatal description is extremely rare as the fetal phenotype is often not present during pregnancy. Trisomy 8p Syndrome is characterized by heterogenous phenotype, with the most frequent components to be cardiac malformation, developmental and intellectual delay. Its prenatal diagnosis is very rare due to the unspecific sonographic features of the affected fetuses. We present a very rare case of a fetus with multiple anomalies diagnosed during the second trimester whose genomic analysis revealed a 18p Deletion and 8p trisomy Syndrome. This is the first case where this combination of DNA mutations has been described prenatally and the second case in general. The presentation of this case, as well as the detailed review of all described cases, aim to expand the existing knowledge regarding this rare condition facilitating its diagnosis in the future.

Clinical and genomic characterization of 8p cytogenomic disorders

PURPOSE

To provide a detailed clinical and cytogenomic summary of individuals with chromosome 8p rearrangements of invdupdel(8p), del(8p), and dup(8p).

METHODS

We enrolled 97 individuals with invdupdel(8p), del(8p), and dup(8p). Clinical and molecular data were collected to delineate and compare the clinical findings and rearrangement breakpoints. We included additional 5 individuals with dup(8p) from the literature for a total of 102 individuals.

RESULTS

Eighty-one individuals had recurrent rearrangements of invdupdel(8p) (n = 49), del(8p)_distal (n = 4), del(8p)_proximal (n = 9), del(8p)_proximal&distal (n = 12), and dup(8p)_proximal (n = 7). Twenty-one individuals had nonrecurrent rearrangements. While all individuals had neurodevelopmental features, the frequency and severity of clinical findings were higher in individuals with invdupdel(8p), and with larger duplications. All individuals with GATA4 deletion had structural congenital heart defects; however, the presence of structural heart defects in some individuals with normal GATA4 copy number suggests there are other potentially contributing gene(s) on 8p.

CONCLUSION

Our study may inform families and health-care providers about the associated clinical findings and severity in individuals with chromosome 8p rearrangements, and guide researchers in investigating the underlying molecular and biological mechanisms by providing detailed clinical and cytogenomic information about individuals with distinct 8p rearrangements.

De novo 8p21.3→ p23.3 Duplication With t(4;8)(q35;p21.3) Translocation Associated With Mental Retardation, Autism Spectrum Disorder, and Congenital Heart Defects: Case Report With Literature Review

Duplications of chromosome 8p lead to rare genetic conditions characterized by variable phenotypes. 8p21 and 8p23 duplications were associated with mental retardation but only 8p23 duplication was associated with heart defects. 8p22→ p21.3 duplications were associated with an autism spectrum disorder in several cases. We present a rare case with a de novo duplication of the entire 8p21.3→ p23.3 region, documented by karyotype, FISH, and array CGH, with t(4;8)(q35;p21.3) translocation in a 7 years-old girl. She was referred for genetic counseling at the age of 20 months due to mild dysmorphic facial features, psychomotor retardation, and a noncyanotic heart defect. Another examination carried out at the age of 5 years, enabled the diagnosis of autism spectrum disorder and attention deficit hyperactivity disorder. Upon re-examination after two years she was diagnosed with autism spectrum disorder, attention deficit hyperactivity disorder, liminal intellect with cognitive disharmony, delay in psychomotor acquisitions, developmental language delay, an instrumental disorder, and motor coordination disorder. Cytogenetic analysis using GTG technique revealed the following karyotype: 46,XX,der(4),t(4;8)(q35;p21.3). The translocation of the duplicated 8pter region to the telomeric region 4q was confirmed by FISH analysis (DJ580L5 probe). Array CGH showed: arr[GRCh37]8p23.3p21.3(125733_22400607) × 3. It identified a terminal duplication, a 22.3 Mb copy number gain of chromosome 8p23.3-p21.3, between 125,733 and 22,400,607. In this case, there is a de novo duplication of a large chromosomal segment, which was translocated to chromosome 4q. Our report provides additional data regarding neuropsychiatric features in chromosome 8p duplication. The phenotypic consequences in our patient allow clinical-cytogenetic correlations and may also reveal candidate genes for the phenotypic features.

New Insights into the Impact of Genome-Wide Copy Number Variations on Complex Congenital Heart Disease in Saudi Arabia

Congenital heart diseases (CHDs) are complex traits that manifest in diverse clinical phenotypes such as the Tetralogy of Fallot (TOF), valvular and ventricular/atrial septal defects. Genetic mechanisms of CHDs have remained largely unclear to date. Copy number variations (CNVs) have been implicated in many complex diseases but their impact has not been examined extensively in various forms of CHD lesions. We report in this study, to the best of our knowledge, the largest cohort of Saudi Arab CHD patients to date who were evaluated using genome-wide CNV analysis. In a sample of 134 Saudi Arab patients with CHD, 66 exhibited pathogenic or likely pathogenic CNVs. Notably, 21 copy number gains and 11 copy number losses were detected that encompassed 141 genes and 146 genes, respectively. The most frequent gains were on 17q21.31, 8p11.21, and 22q11.23, whereas the losses were primarily localized to 16p11.2. Interestingly, all lesions have had gains at 17q21.31. Septal defects had also gains at 8p11.21 and 22q11.23, valvular lesions at 8p11.21, 22q11.23, and 2q13, and TOF at 16p11.2. Functional and network analyses demonstrated that cardiovascular and nervous system development and function as well as cell death/survival were most significantly associated with CNVs, thus highlighting the potentially important genes likely to be involved in CHD, including NPHP1, PLCB1, KANSL1, and NR3C1. In conclusion, this genome-wide analysis identifies a high frequency of CNVs mostly in patients with septal defects, primarily influencing cardiovascular developmental and functional pathways, thereby offering a deeper insight into the complex networks involved in CHD pathogenesis.