Sleep in Children With Pallister Killian Syndrome: A Prospective Clinical and Videopolysomnographic Study

Objectives: Pallister-Killian syndrome (PKS) is a rare genetic disorder with multi-organ involvement caused by mosaic tetrasomy of chromosome 12p. Although many caregivers report the presence of impaired sleep in their children, there are no clear data in the literature on this issue and no systematic study has ever been performed. With this study, we aimed to characterize the features of sleep in Pallister-Killian syndrome and identify the possible influence of clinical and demographic features. Moreover, our aim was to verify the effectiveness of conventional screening questionnaires in this particular group of patients.Methods: We prospectively enrolled 14 patients aged 1–17 years in collaboration with PKS Kids Italia ONLUS. The Sleep Disturbance Scale for Children (SDSC) questionnaire was administered to caregivers. Then, video polysomnography (VPSG) of at least 24 h was performed and results were compared with a same-aged control group.Results: A total of 92% of patients had abnormal SDSC scores, extremely high in the “disorder of initiating and maintaining sleep” (DIMS) and “sleep breathing disorders” (SBD) subscales. VPSG showed a significantly impaired macrostructure in PKS patients, with a higher Arousal Index (p < 0.00001) and percentage of time spent in N3 (p < 0.00001), and reduced Sleep Efficiency (p = 0.0006). After dividing both PKS and controls into two groups based on median age, some peculiarities emerged: the younger group had higher Awakenings Index (p = 0.0207) and percentage of time spent in N1 (p = 0.015) while the older group showed higher time in bed (TIB) (p = 0.0485), compared with controls. Due to poor compliance, the Apnea-Hypopnea Index (AHI) was evaluated only for 10 PKS children, being significantly increased (p = 0.0427) compared with controls. SBD subscale scores in SDSC were significantly related to AHI values in VPSG (p = 0.0099).Conclusions: This study constitutes the first attempt to describe the sleep pattern in PKS. Despite small numbers due to the rarity of the syndrome, our VPSG results confirm the high prevalence of sleep disorders (SDs) in these patients. It is therefore essential to investigate and treat them. The SDSC scale is a good screening tool for early detection also in these patients, with particular sensitivity in detecting breathing disorders.

Iso-chromosome 12p Analysis by Fluorescent In-Situ Hybridization: An Academic Institutional Experience

Introduction/Objective Chromosome 12 abnormalities like iso-chromosome 12p (i12p) and amplification of 12p are seen in majority (89%) of the primary and metastatic testicular germ cell tumors (TGCTs). i12p can be detected by karyotyping, fluorescent in-situ hybridization (FISH) or reverse transcriptase polymerase chain reaction. The aim of this study was to review i12p FISH data at our institution and assess the clinical utility. Methods/Case Report Laboratory information system was queried over a period of 15 years to search for cases where i12p FISH test was requested. FISH test was performed using TelVysion 12p telomeric probe and CEP 12 centromere probe on paraffin-embedded tissue or cell blocks. A ratio of 12ptel/CEP12 signal of 1.4 or greater was considered as positive. Patient demographics, clinical presentation, pathologic findings, and follow-up data were documented and correlated. Results (if a Case Study enter NA) Total 58 cases were identified with an age range of 14 to 76 years. Majority were male (M=52, F=6). Of these cases, 15 were testicular and 43 extra-testicular cases that included resection (n=35), biopsy (n=20) and cell-blocks (n=3). i12p was detected in 8 out of 15 testicular cases while i12p was detected in 16 out of the 43 extra-testicular cases. The extra- testicular cases included 17 retroperitoneal lesions, 8 lesions from the mediastinum, 6 lymph nodes from other sites and 12 miscellaneous lesions. Using pathology diagnosis with immunohistochemistry as gold standard, overall sensitivity was 60% and specificity was 86%. There were 3 false positive cases [Benign testicular parenchyma (n=1), suspicious for germ cell neoplasia in-situ (n=1) and undifferentiated epithelioid neoplasm (n=1)]. Conclusion Our results show that although the sensitivity was limited, FISH test for i12p demonstrated high specificity(86%) for diagnosis of primary or metastatic TGCTs. As an adjunct test, i12p FISH can help identify and further characterize a significant number of GCTs with unusual morphology or clinical presentation.

Structural variant evolution after telomere crisis

Telomere crisis contributes to cancer genome evolution, yet only a subset of cancers display breakage-fusion-bridge (BFB) cycles and chromothripsis, hallmarks of experimental telomere crisis identified in previous studies. We examine the spectrum of structural variants (SVs) instigated by natural telomere crisis. Eight spontaneous post-crisis clones did not show prominent patterns of BFB cycles or chromothripsis. Their crisis-induced genome rearrangements varied from infrequent simple SVs to more frequent and complex SVs. In contrast, BFB cycles and chromothripsis occurred in MRC5 fibroblast clones that escaped telomere crisis after CRISPR-controlled telomerase activation. This system revealed convergent evolutionary lineages altering one allele of chromosome 12p, where a short telomere likely predisposed to fusion. Remarkably, the 12p chromothripsis and BFB events were stabilized by independent fusions to chromosome 21. The data establish that telomere crisis can generate a wide spectrum of SVs implying that a lack of BFB patterns and chromothripsis in cancer genomes does not indicate absence of past telomere crisis.

Between a Rock and a Hard Place: An Epigenetic-Centric View of Testicular Germ Cell Tumors

Compared to many common solid tumors, the main genetic drivers of most testicular germ cell tumors (TGCTs) are unknown. Decades of focus on genomic alterations in TGCTs including awareness of a near universal increase in copies of chromosome 12p have failed to uncover exceptional driver genes, especially in genes that can be targeted therapeutically. Thus far, TGCT patients have missed out on the benefits of targeted therapies available to treat most other malignancies. In the past decade there has been a greater appreciation that epigenetics may play an especially prominent role in TGCT etiology, progression, and hypersensitivity to conventional chemotherapy. While genetics undoubtedly plays a role in TGCT biology, this mini-review will focus on the epigenetic “states” or features of testicular cancer, with an emphasis on DNA methylation, histone modifications, and miRNAs associated with TGCT susceptibility, initiation, progression, and response to chemotherapy. In addition, we comment on the current status of epigenetic-based therapy and epigenetic biomarker development for TGCTs. Finally, we suggest a unifying “rock and a hard place” or “differentiate or die” model where the tumorigenicity and curability of TGCTs are both dependent on common but still ill-defined epigenetic states.

Bifid cardiac apex in Pallister-Killian syndrome

Aim: Pallister-Killian syndrome (PKS) is a rare chromosomal disorder, caused by tissue-limited mosaicism for an isochromosome 12p. Prenatal diagnosis of PKS is generally incidental. Although clinical presentation of PKS varies, cytogenetic findings are constant, and include a tetrasomy of chromosome 12p. We report a case of prenatally diagnosed PKS with unique dysmorphic feature: bifid cardiac apex, a type of morphology that has not been documented before. Case presentation: Our patient was the 38-year-old pregnant woman who underwent amniocentesis. Cytogenetic analysis of amniotic fluid detected a mosaic karyotype with a supernumerary chromosome (SMC) in 64 % of fetal amniocytes. To determine the chromosomal origin of SMC, fluorescence in situ hybridization was performed and tetrasomy 12p was confirmed: mos 47,XY,+mar[18]/46,XY[10].ishi(12p)(8M16/SP6++,CEP12+,VIJyRM2196-). Ultrasound examination showed a fetus with cleft lip, echogenic focus in the left ventricle of the heart and shortened fetal long bones. After receiving a genetic counseling for PKS, the woman requested a termination of pregnancy. A postmortem inspection of the fetus revealed a complex heart anomaly that includes bifid cardiac apex and ventricular septal defect. Conclusions: This report expands the clinical manifestations of PKS with a unique feature of bifid cardiac apex, and highlights the targeted prenatal diagnosis of PKS if specific ultrasound markers are present.

Clinical Variability of Pallister–Killian Syndrome in Two Egyptian Patients

Pallister–Killian syndrome (PKS) is a rare sporadic genetic disorder caused by a mosaic tetrasomy of chromosome 12p, which mainly manifests with craniofacial dysmorphism, intellectual disability (ID), auditory disturbance, epilepsy, and a variety of congenital malformations. The diagnosis of PKS can be complicated due to the phenotypic variation, and an overlap with other syndromes makes the molecular cytogenetic test necessary for a correct diagnosis. We identified two unrelated patients with typical facial features of PKS, including bitemporal alopecia, hypertelorism, and abnormal ears. Furthermore, the two patients had pigmentary skin anomalies, broad and short hands and fingers, and hypotonia. However, they differed in the degree of ID and ophthalmological findings. Patient 1 showed profound ID and poor macular function, whereas patient 2 had moderate ID and normal fundus. Mosaic tetrasomy of chromosome 12p was found in 40 and 25% of the cells of patients 1 and 2, respectively, by fluorescent in situ hybridization of cultured skin fibroblasts. The higher percentage of mosaic cells with tetrasomy 12p found in patient 1 may explain the severe phenotype. This report expands the clinical manifestations of PKS and highlights the variable expressivity of clinical features in relation to the cytogenetics findings.