Spontaneous remission and loss of monosomy 7: a window of opportunity for young children with SAMD9L syndrome.

Monosomy 7 is the most common cytogenetic abnormality in pediatric myelodysplastic syndrome (MDS) and associated with a high risk of disease progression. However, in young children, spontaneous loss of monosomy 7 with concomitant hematologic recovery has been described, especially in the presence of germline mutations in SAMD9 and SAMD9L genes. Here, we report on our experience of close surveillance instead of upfront hematopoietic stem cell transplantation (HSCT) in seven patients diagnosed with SAMD9L syndrome and monosomy 7 at a median age of 0.6 years (range, 0.4-2.9). Within 14 months from diagnosis, three children experienced spontaneous hematological remission accompanied by a decrease in monosomy 7 clone size. Subclones with somatic SAMD9L mutations in cis were identified in five patients, three of whom attained hematological remission. Two patients acquired RUNX1 and EZH2 mutations during the observation period, of whom one progressed to myelodysplastic syndrome with excess of blasts (MDS-EB). Four patients underwent allogeneic HSCT at a median time of 26 months (range, 14-40) from diagnosis for MDSEB, necrotizing granulomatous lymphadenitis, persistent monosomy 7, and severe neutropenia. At last follow-up, six patients were alive, while one passed away due to transplant-related causes. These data confirm previous observations that monosomy 7 can be transient in young children with SAMD9L syndrome. However, they also indicate that delaying HSCT poses a substantial risk of severe infection and disease progression. Finally, surveillance of patients with SAMD9L syndrome and monosomy 7 is critical to define the evolving genetic landscape and to determine the appropriate timing of HSCT (clinicaltrials gov. Identifier: NCT00662090).

¿Qué puede esconder el retraso global del desarrollo? A propósito de un caso de causa genética / What can Global Developmental Delay Conceal? Apropos of a Case with a Genetic Cause

Se presenta un niño de 6 años con antecedente de retraso del lenguaje que llevó a sus padres a realizar múltiples consultas. En un primer momento, su cuadro fue interpretado como parte de un retraso global del desarrollo. Posteriormente, el paciente presentó convulsiones y episodios de descompensación metabólica, comenzando desde entonces su seguimiento por los Servicios de neurología, genética y metabolismo. Finalmente, tras varios estudios complementarios, por medio de un exoma trío se arribó al diagnóstico de síndrome de microduplicación del cromosoma 7q11.23, lo que justifica tanto el retraso global de desarrollo del paciente como su clínica neurológica. (AU)

A six-year-old boy presents with a history of language delay that led his parents to make multiple consultations. At first, we interpreted his condition as part of a global developmental delay. Subsequently, the patient presented seizures and episodes of metabolic decompensation, and since then, he had to be followed up by neurology, genetics, and metabolism services. Finally, after several complementary studies, following a trio exome analysis, we diagnosed chromosome 7q11.23 microduplication syndrome, which explains his global developmental delay and neurological symptoms. (AU)

[Clinical features and genetic analysis of two children with Williams-Beuren syndrome].

OBJECTIVE: To explore the clinical and genetic characteristics of two children with Williams-Beuren syndrome (WBS). METHODS: Two children who had presented at the Department of Pediatrics, General Hospital of Ningxia Medical University respectively on January 26 and March 18, 2021 were selected as the study subjects. Clinical data and results of genetic testing of the two patients were analyzed. RESULTS: Both children had featured developmental delay, characteristic facies and cardiovascular malformation. Child 1 also had subclinical hypothyroidism, whilst child 2 had occurrence of epilepsy. Genetic testing revealed that child 1 has harbored a 1.54 Mb deletion in the 7q11.23 region, whilst child 2 has a 1.53 Mb deletion in the same region, in addition with a c.158G>A variant of the ATP1A1 gene and a c.12181A>G variant of the KMT2C gene. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.158G>A and c.12181A>G variants were rated as variants of unknown significance (PM1+PM2_Supporting+PP2+PP3；PM2_Supporting). CONCLUSION: Both children had characteristic features of WBS, for which deletions of the 7q11.23 region may be accountable. For children manifesting developmental delay, facial dysmorphism and cardiovascular malformations, the diagnosis of WBS should be suspected, and genetic testing should be recommended to confirm the diagnosis.

L-asparaginase as an efficient salvage therapy for refractory acute myeloid leukemia with chromosome 7 abnormalities: a case series.

Acute myeloid leukemia (AML) with chromosome 7 abnormalities has a dismal prognosis due to a poor complete remission (CR) rate after induction chemotherapy. Although various salvage therapies for refractory AML have been developed for adults, few salvage therapies are available for children. Here, we report the cases of three patients with refractory AML with chromosome 7 abnormalities (Patient 1, with inv(3)(q21;3q26.2) and monosomy 7; Patient 2, with der(7)t(1;7)(?;q22); patient 3, with monosomy 7) who were successfully treated with L-asparaginase (L-ASP) as salvage therapy. All three patients achieved CR several weeks after L-ASP treatment, and two patients successfully underwent hematopoietic stem cell transplantation (HSCT). Patient 2 relapsed after the second HSCT in the form of an intracranial lesion, but achieved and sustained CR for 3 years with weekly L-ASP maintenance therapy. Immunohistochemical staining for asparagine synthetase (ASNS), whose gene is located at 7q21.3, was performed for each patient. The result was negative in all patients, which suggests that haploid 7q21.3 and other chromosome 7 abnormalities leading to haploinsufficiency of ASNS contribute to a high susceptibility to L-ASP. In conclusion, L-ASP is a promising salvage therapy for refractory AML with chromosome 7 abnormalities, which are associated with ASNS haploinsufficiency.

Parallel deletion and duplication at 7q11.23 in a silent carrier for two reciprocal syndromic disorders.

Partial deletions at chromosome 7q11.23 are causative for the autosomal-dominant Williams-Beuren syndrome (WBS), whereas the partial duplication of this region leads to the 7q11.23 duplication syndrome. Both syndromes are highly penetrant and occur with a frequency of 1:7500-10,000 (WBS) and 1:13,000-20,000 (7q11.23 duplication syndrome). They are associated with multiple organ defects, intellectual disability, and typical facial dysmorphisms showing broad phenotypic variability. The 7q11.23 region is susceptible to chromosomal rearrangements due to flanking segmental duplications and regions of long repetitive DNA segments. Here, we report on a family with two children affected by WBS and clinically unaffected parents. Interestingly, metaphase fluorescence in situ hybridization (FISH) revealed a deletion on 7q11.23 in the father. Intensive genetic testing, using interphase FISH, whole genome sequencing and optical genome mapping led to the confirmation of a 1.5 Mb deletion at one 7q11.23 allele and the identification of a reciprocal 1.8 Mb duplication at the other allele. This finding is highly important regarding genetic counseling in this family. The father is a silent carrier for two syndromic disorders, thus his risk to transmit a disease-causing allele is 100%. To the best of our knowledge we, here, report on the first case in which the phenotype of a microdeletion/microduplication syndrome was compensated by its reciprocal counterpart.

Autoimmune Myelofibrosis in a 12-Year-old Male With Monosomy 7, Systemic Lupus Erythematous and Lupus Nephritis: A Case Report and Review of the Literature.

Complete or partial loss of chromosome 7 is a common and well-known cytogenetic abnormality associated with preleukemic myelodysplasia and myeloid leukemia but not with autoimmune myelofibrosis. Detection of this molecular change represents poor prognosis. When malignant transformation occurs, the condition tends to be chemotherapy-resistant requiring haematopoietic stem cell transplantation (HSCT) to obtain a cure. Disappearance after immunosuppressive therapy has been documented in children with hematological disorders but not in association with cyclophosphamide and systemic lupus erythematous.We present the interesting case of a 12-year-old male with monosomy 7, systemic lupus erythematous, and lupus nephritis with the resolution of the monosomy 7 and autoimmune myelofibrosis after treatment with cyclophosphamide, along with a review of the literature.

Clinical features and genetic analysis of two children with Williams-Beuren syndrome / 中华医学遗传学杂志

OBJECTIVE@#To explore the clinical and genetic characteristics of two children with Williams-Beuren syndrome (WBS).@*METHODS@#Two children who had presented at the Department of Pediatrics, General Hospital of Ningxia Medical University respectively on January 26 and March 18, 2021 were selected as the study subjects. Clinical data and results of genetic testing of the two patients were analyzed.@*RESULTS@#Both children had featured developmental delay, characteristic facies and cardiovascular malformation. Child 1 also had subclinical hypothyroidism, whilst child 2 had occurrence of epilepsy. Genetic testing revealed that child 1 has harbored a 1.54 Mb deletion in the 7q11.23 region, whilst child 2 has a 1.53 Mb deletion in the same region, in addition with a c.158G>A variant of the ATP1A1 gene and a c.12181A>G variant of the KMT2C gene. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.158G>A and c.12181A>G variants were rated as variants of unknown significance (PM1+PM2_Supporting+PP2+PP3；PM2_Supporting).@*CONCLUSION@#Both children had characteristic features of WBS, for which deletions of the 7q11.23 region may be accountable. For children manifesting developmental delay, facial dysmorphism and cardiovascular malformations, the diagnosis of WBS should be suspected, and genetic testing should be recommended to confirm the diagnosis.

Clinical and molecular profiling of AML patients with chromosome 7 or 7q deletions in the context of TP53 alterations and venetoclax treatment.

Deletions in chromosome 7 (del(7)) or its long arm (del(7q)) constitute the most common adverse cytogenetic events in acute myeloid leukemia (AML). We retrospectively analyzed 243 treatment-naive patients with AML and del(7) (168/243; 69%) or del(7q) (75/243; 31%) who did not receive any myeloid-directed therapy prior to AML diagnosis. This is the largest comprehensive clinical and molecular analysis of AML patients with del(7) and del(7q). Our results show that relapse-free survival was significantly longer for AML patients with del(7q) compared to del(7), but the overall survival and remission duration were similar. TP53 mutations and del5/5q were the most frequent co-occurring mutations and cytogenetic abnormalities, and conferred worse outcomes in del(7) and del(7q) patients. Venetoclax-based treatments were associated with worse outcomes in TP53 mutated AML patients with del(7) or del(7q), as well as del(7) with TP53 wildtype status, requiring further investigation.

A 79-kb paternally inherited 7q32.2 microdeletion involving MEST in a patient with a Silver-Russell syndrome-like phenotype.

Maternal uniparental disomy of human chromosome 7 [upd(7)mat] is well-characterized as a cause of the growth disorder Silver-Russell syndrome (SRS). However, the causative gene is not currently known. There is growing evidence that molecular changes at the imprinted MEST region in 7q32.2 are associated with a phenotype evocative of SRS. This report details a patient with a SRS-like phenotype and a paternally inherited microdeletion of 79 kilobases (35-fold smaller than the previously reported smallest deletion) in the 7q32.2 region. This microdeletion encompasses only five genes, including MEST, which corroborates the hypothesis that MEST plays a central role in the 7q32.2 microdeletion growth disorder, as well as further implicating MEST in upd(7)mat SRS itself.

Rare variants in previously identified linkage regions associated with carotid plaque in Dominican Republic families.

Carotid plaque is a subclinical measure of atherosclerosis. We have previously shown measures of carotid plaque to be heritable in a sample of 100 Dominican families and found evidence for linkage and association of common variants (CVs) on 7q36, 11p15, 14q32 and 15q23 with plaque presence. Our current study aimed to refine these regions further and identify rare variants (RVs) influencing plaque presence. Therefore, we performed targeted sequencing of the one LOD unit down region on 7q36, 11p15, 14q32 and 15q23 in 12 Dominican families with evidence for linkage to plaque presence. Gene-based RV analyses were performed using the Sequence Association Test for familial data (F-SKAT) under two filtering algorithms; 1. all exonic RVs and 2. non-synonymous RVs. Replication analyses were performed using a sample of 22 Dominican families and 556 unrelated Dominicans with Exome Array data. To identify additional non-synonymous RVs influencing plaque, we looked for co-segregation of RVs with plaque in each of the sequenced families. Our most strongly associated gene with evidence for replication was AMPD3 which showed suggestive association with plaque presence in the sequenced families (exonic RV p = 0.003, nonsynonymous RV p = 0.005) and replication families (exonic RV p = 0.04, nonsynonymous RV p = 0.02). Examination of the sequenced family pedigrees revealed two missense variants on chromosome 11 which co-segregated with plaque presence in one of our families; rs61751342 (located in DENND2B), and rs61760882 (located in RNF141). The rs61751342 missense variant is an eQTL for SCUBE2 in the atrial appendage. Notably, SCUBE2 encodes a protein which interacts with vascular endothelial growth factor (VEGF) receptor 2 to regulate VEGF-induced angiogenesis, thus providing biologic plausibility for this gene in atherosclerosis. In conclusion, using targeted sequencing of previously-identified linkage regions, we have identified suggestive evidence for the role of RVs in carotid plaque pathogenesis.

The significance of CUX1 and chromosome 7 in myeloid malignancies.

PURPOSE OF REVIEW: Loss of chromosome 7 has long been associated with adverse-risk myeloid malignancy. In the last decade, CUX1 has been identified as a critical tumor suppressor gene (TSG) located within a commonly deleted segment of chromosome arm 7q. Additional genes encoded on 7q have also been identified as bona fide myeloid tumor suppressors, further implicating chromosome 7 deletions in disease pathogenesis. This review will discuss the clinical implications of del(7q) and CUX1 mutations, both in disease and clonal hematopoiesis, and synthesize recent literature on CUX1 and other chromosome 7 TSGs. RECENT FINDINGS: Two major studies, including a new mouse model, have been published that support a role for CUX1 inactivation in the development of myeloid neoplasms. Additional recent studies describe the cellular and hematopoietic effects from loss of the 7q genes LUC7L2 and KMT2C/MLL3, and the implications of chromosome 7 deletions in clonal hematopoiesis. SUMMARY: Mounting evidence supports CUX1 as being a key chromosome 7 TSG. As 7q encodes additional myeloid regulators and tumor suppressors, improved models of chromosome loss are needed to interrogate combinatorial loss of these critical 7q genes.

Therapy-related Myeloid Neoplasms in Children: A Single-institute Study.

Therapy-related myeloid neoplasm (t-MN) in the pediatric population is not well characterized. We studied 12 pediatric patients diagnosed with t-MN in our institution since 2006. The median age at the t-MN diagnoses was 14.8 years (range, 9 to 20 y). The primary malignancies included 9 solid tumors and 3 hematopoietic malignancies. Rhabdomyosarcoma (n=4) was the most common primary malignancy. Five of the 9 patients with solid tumors and all 3 patients with hematopoietic malignancies had primary neoplasms involving bone marrow. The median latency period was 5.2 years (range, 1.8 to 13.8 y). Thrombocytopenia was present in all patients at the t-MN diagnoses. Complete or partial monosomy of chromosome 5 or 7 were the 2 most common cytogenetic abnormalities. A quarter of patients demonstrated a genetic predisposition to t-MN: 1 with Li-Fraumeni syndrome with a germline TP53 R248Q mutation, 1 with Noonan syndrome with a somatic mutation (PTPN11 S502T), and 1 with a constitutive chromosomal translocation [t(X;9)(p22;q34)] and a germline TP53 L130V mutation. Outcomes remain poor. Two patients survived 3 and 5.1 years after hematopoietic stem cell transplantation.

Prenatal ultrasound-assisted identification of multiple malformations caused by a deletion in the long-arm end of chromosome 7 and review of the literature.

Clinical cases of chromosome 7 long-arm end deletion are rare. Generally, 7q terminal deletion syndrome results in complex clinical phenotypes, such as microcephaly, growth and development retardation, holoprosencephaly, and sacral hypoplasia. Herein, we report the genetic and clinical features of a fetus with multiple malformations observed by prenatal ultrasound. The results showed that there was a large fragment deletion of approximately 27.7 Mb in 7q32.3-qter. The induced fetus showed facial abnormalities of cleft lip and palate, and some organ structural abnormalities (such as diaphragmatic hernia and polycystic renal dysplasia) were observed by autopsy and pathology. To provide more reliable information for disease diagnosis and genetic counseling, we reviewed and analyzed the reported cases of isolated 7q terminal syndrome.

Greig Cephalopolysyndactyly Contiguous Gene Syndrome: Case Report and Literature Review.

Greig cephalopolysyndactyly syndrome (GCPS) is a rare genetic disorder (about 200 cases reported), characterized by macrocephaly, hypertelorism, and polysyndactyly. Most of the reported GCPS cases are the results of heterozygous loss of function mutations affecting the GLI3 gene (OMIM# 175700), while a small proportion of cases arise from large deletions on chromosome 7p14 encompassing the GLI3 gene. To our knowledge, only 6 patients have been reported to have a deletion with an exact size (given by genomic coordinates) and a gene content larger than 1 Mb involving the GLI3 gene. This report presents a patient with Greig cephalopolysyndactyly contiguous gene syndrome (GCP-CGS) diagnosed with a large, 18 Mb deletion on chromosome 7p14.2-p11.2. Similar cases are reviewed in the literature for a more accurate comparison between genotype and phenotype.

Divergent leukaemia subclones as cellular models for testing vulnerabilities associated with gains in chromosomes 7, 8 or 18.

Haematopoietic malignancies are frequently characterized by karyotypic abnormalities. The development of targeted drugs has been pioneered with compounds against gene products of fusion genes caused by chromosomal translocations. While polysomies are equally frequent as translocations, for many of them we are lacking therapeutic approaches aimed at synthetic lethality. Here, we report two new cell lines, named MBU-7 and MBU-8, that differ in complete trisomy of chromosome18, a partial trisomy of chromosome 7 and a tetrasomy of the p-arm of chromosome 8, but otherwise share the same mutational pattern and complex karyotype. Both cell lines are divergent clones of U-937 cells and have the morphology and immunoprofile of monocytic cells. The distinct karyotypic differences between MBU-7 and MBU-8 are associated with a difference in the specific response to nucleoside analogues. Taken together, we propose the MBU-7 and MBU-8 cell lines described here as suitable in vitro models for screening and testing vulnerabilities that are associated with the disease-relevant polysomies of chromosome 7, 8 and 18.

Single cell T cell landscape and T cell receptor repertoire profiling of AML in context of PD-1 blockade therapy.

In contrast to the curative effect of allogenic stem cell transplantation in acute myeloid leukemia via T cell activity, only modest responses are achieved with checkpoint-blockade therapy, which might be explained by T cell phenotypes and T cell receptor (TCR) repertoires. Here, we show by paired single-cell RNA analysis and TCR repertoire profiling of bone marrow cells in relapsed/refractory acute myeloid leukemia patients pre/post azacytidine+nivolumab treatment that the disease-related T cell subsets are highly heterogeneous, and their abundance changes following PD-1 blockade-based treatment. TCR repertoires expand and primarily emerge from CD8+ cells in patients responding to treatment or having a stable disease, while TCR repertoires contract in therapy-resistant patients. Trajectory analysis reveals a continuum of CD8+ T cell phenotypes, characterized by differential expression of granzyme B and a bone marrow-residing memory CD8+ T cell subset, in which a population with stem-like properties expressing granzyme K is enriched in responders. Chromosome 7/7q loss, on the other hand, is a cancer-intrinsic genomic marker of PD-1 blockade resistance in AML. In summary, our study reveals that adaptive T cell plasticity and genomic alterations determine responses to PD-1 blockade in acute myeloid leukemia.

Overview of clinical and genetic features of CML patients with variant Philadelphia translocations involving chromosome 7: A case series.

Variant Philadelphia (Ph) translocations involving chromosome 7 are rarely seen in Chronic Myeloid Leukemia (CML) patients. It is aimed to contribute new cases to the literature by reviewing the cases in our archive and shed light into the understanding of the role of chromosome 7 in CML. This study was carried out in 237 newly diagnosed CML patients with variant Ph translocations. Among the patients, those with variant Ph translocation involving chromosome 7 were evaluated in terms of clinical and genetic characteristics. Chromosome analysis was performed on 24 and 48 h of bone marrow cultures. FISH analysis was performed with BCR-ABL1 dual color dual fusion translocation probes. BCR-ABL1 transcript levels were analysed by QRT-PCR and results were reported as BCR-ABL1/ABL1 (BCR-ABL1 (IS) %) according to international scale. Four of the patients had variant Ph translocations including chromosome 7. The karyotypes were 46,XX,t(7;9;22)(p13;q34;q11); 46,XX,t(7;9;22)(p21;q34;q11); 46,XX,t(7;9;22)(q22;q34;q11) and 46,XY,t(7;9;22)(q22;q34;q11). The breakpoints demonstrated by cytogenetic analysis were confirmed by FISH analysis. Monitoring by QRT-PCR showed that patients with variant Ph translocation including 7p13 and 7p21 had a dramatic decrease in BCR-ABL1 levels resulting in complete hematological, complete cytogenetic and deep molecular responses. Despite achieving complete hematological, complete cytogenetic response in two patients with variant Philadelphia translocation, including 7q22, no major molecular response was achieved and both patients are still in the warning category. Response to tyrosine kinase inhibitör therapy may be associated with both the variant translocation mechanism and new gene interactions that occur due to the breakpoints of additional chromosomes involved in translocation.

Autism Spectrum Disorders: Analysis of Mobile Elements at 7q11.23 Williams-Beuren Region by Comparative Genomics.

Autism spectrum disorders (ASD) are a group of complex neurodevelopmental disorders, characterized by a deficit in social interaction and communication. Many genetic variants are associated with ASD, including duplication of 7q11.23 encompassing 26-28 genes. Symmetrically, the hemizygous deletion of 7q11.23 causes Williams-Beuren syndrome (WBS), a multisystem disorder characterized by "hyper-sociability" and communication skills. Interestingly, deletion of four non-exonic mobile elements (MEs) in the "canine WBS locus" were associated with the behavioral divergence between the wolf and the dog and dog sociability and domestication. We hypothesized that indel of these MEs could be involved in ASD, associated with its different phenotypes and useful as biomarkers for patient stratification and therapeutic design. Since these MEs are non-exonic they have never been discovered before. We searched the corresponding MEs and loci in humans by comparative genomics. Interestingly, they mapped on different but ASD related genes. The loci in individuals with phenotypically different autism and neurotypical controls were amplified by PCR. A sub-set of each amplicon was sequenced by Sanger. No variant resulted associated with ASD and neither specific phenotypes were found but novel small-scale insertions and SNPs were discovered. Since MEs are hyper-methylated and epigenetically modulate gene expression, further investigation in ASD is necessary.