Girl with combined cellular immunodeficiency, pancytopenia, malformations, deletion 11q23.3 --> qter, and trisomy 8q24.3 --> qter

Case report: ETS1 gene deletion associated with a low number of recent thymic emigrants in three patients with Jacobsen syndrome

Jacobsen syndrome is a rare genetic disorder associated with a terminal deletion in chromosome 11. The clinical presentation is variable. Although immunodeficiency has been described in patients with Jacobsen syndrome, a clear genotype-phenotype correlation has not yet been established. Here, we report on the immunologic phenotypes of four patients with Jacobsen syndrome. All four patients showed one or more atypical immunologic features. One patient suffered from recurrent viral infections, two patients had experienced a severe bacterial infection and one had received antibiotic prophylaxis since early childhood. One patient had experienced severe, transient immune dysregulation. Hypogammaglobulinemia and low B cell counts were found in two patients, while the number of recent thymic emigrants (CD31+CD45RA+ CD4 cells) was abnormally low in three. When considering the six immune-related genes located within the affected part of chromosome 11 (ETS1, TIRAP, FLI1, NFRKB, THYN1, and SNX19), only the ETS1 gene was found be deleted in the three patients with low numbers of recent thymic emigrants and non-switched memory B cells. Our findings support the hypothesis whereby Jacobsen syndrome is associated with a combined immunodeficiency with variable presentation. Further investigations of potential genotype-phenotype correlations are warranted and might help to personalize patient management in individuals lacking immune-related genes. In addition, we recommend immunologic follow-up for all patients with Jacobsen syndrome, as immune abnormalities may develop over time.

Patients with Chromosome 11q Deletions Are Characterized by Inborn Errors of Immunity Involving both B and T Lymphocytes

Disorders of the long arm of chromosome 11 (11q) are rare and involve various chromosomal regions. Patients with 11q disorders, including Jacobsen syndrome, often present with a susceptibility for bacterial and prolonged viral and fungal infections partially explained by hypogammaglobulinemia. Additional T lymphocyte or granular neutrophil dysfunction may also be present. In order to evaluate infectious burden and immunological function in patients with 11q disorders, we studied a cohort of 14 patients with 11q deletions and duplications. Clinically, 12 patients exhibited prolonged and repetitive respiratory tract infections, frequently requiring (prophylactic) antibiotic treatment (n = 7), ear-tube placement (n = 9), or use of inhalers (n = 5). Complicated varicella infections (n = 5), chronic eczema (n = 6), warts (n = 2), and chronic fungal infections (n = 4) were reported. Six patients were on immunoglobulin replacement therapy. We observed a high prevalence of low B lymphocyte counts (n = 8), decreased T lymphocyte counts (n = 5) and abnormal T lymphocyte function (n = 12). Granulocyte function was abnormal in 29% without a clinical phenotype. Immunodeficiency was found in patients with terminal and interstitial 11q deletions and in one patient with terminal 11q duplication. Genetically, FLI1 and ETS1 are seen as causative for the immunodeficiency, but these genes were deleted nor duplicated in 4 of our 14 patients. Alternative candidate genes on 11q may have a role in immune dysregulation. In conclusion, we present evidence that inborn errors of immunity are present in patients with 11q disorders leading to clinically relevant infections. Therefore, broad immunological screening and necessary treatment is of importance in this patient group.

Retrospective karyotype study in mentally retarded patients

OBJECTIVE

To describe the chromosomal alterations in patients with mental retardation (MR) using G-banding karyotype analysis.

METHOD

A retrospective study of the results G-banding karyotype analysis of 369 patients investigated for MR was performed. Based on the structural rearrangements found, the authors searched all chromosomal regions related with breakpoints, and these were compared with the literature on MR and databases.

RESULTS

338 (91.6%) normal cases, and 31 (8.4%) with some type of chromosomal abnormality were identified. Among the altered cases, 21 patients (67.8%) were identified with structural chromosomal alterations, nine (29%) with numerical alterations, and one (3.2%) with numerical and structural alterations.

CONCLUSION

Structural chromosomal abnormalities were observed more frequently in this study. G-banding karyotyping contributes to the investigation of the causes of MR, showing that this technique can be useful for initial screening of patients. However, higher resolution techniques such as array based comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MPLA) can detect submicroscopic alterations commonly associated with MR.

A palindrome-mediated recurrent translocation with 3:1 meiotic nondisjunction: the t(8;22)(q24.13;q11.21)

Palindrome-mediated genomic instability has been associated with chromosomal translocations, including the recurrent t(11;22)(q23;q11). We report a syndrome characterized by extremity anomalies, mild dysmorphia, and intellectual impairment caused by 3:1 meiotic segregation of a previously unrecognized recurrent palindrome-mediated rearrangement, the t(8;22)(q24.13;q11.21). There are at least ten prior reports of this translocation, and nearly identical PATRR8 and PATRR22 breakpoints were validated in several of these published cases. PCR analysis of sperm DNA from healthy males indicates that the t(8;22) arises de novo during gametogenesis in some, but not all, individuals. Furthermore, demonstration that de novo PATRR8-to-PATRR11 translocations occur in sperm suggests that palindrome-mediated translocation is a universal mechanism producing chromosomal rearrangements.

Characterization of trisomic natural killer cell abnormalities in a patient with constitutional trisomy 8 mosaicism

Malignancies found in children and adults with constitutional trisomy 8 mosaicism (CT8M) could be in part the consequence of dysfunction of trisomic immune cells. An adult patient exhibiting trisomy in the entire natural killer (NK) cell population has made possible the characterization of trisomy 8-positive NK cells. The study showed normal cytotoxic activity but predominance of an immunosenescent phenotype (CD56(dim)CD94/NKG2(bright)) characterized by a weak response to IL-2, increased upregulation of CD95/Fas, and impaired TNF-alpha production. As these defects may contribute to the escape and expansion of neoplastic cells, the authors hypothesize that cancer predisposition in CT8M may be partly a result of altered immunosurveillance.

Trisomy 8q and partial trisomy 22 in a 43-year-old man with moderate intellectual disability, epilepsy and large cell non-Hodgkin lymphoma

Partial trisomies are chromosome abnormalities resulting in a broad range of malformations depending on the size and location of the chromosomal rearrangement. Whereas diagnosis of these syndromes is usually made in early childhood, few descriptions exist about the clinical picture in adulthood. We report on a patient diagnosed at the age of 43 years with a 47,XY,+der(22)t(8;22)(q24.13;q11.21) karyotype and predominant clinical features of trisomy 8q. To our knowledge, this is the oldest patient described with a partial trisomy 8. The patient presented with moderate intellectual disability, a past history of epilepsy and facial anomalies. In addition, a large cell non-Hodgkin lymphoma was diagnosed in adulthood. Detailed breakpoint mapping by single nucleotide polymorphism (SNP) arrays showed that the derivative chromosome contains a full-length copy of the C-MYC oncogene. Given that trisomy 8q is the most frequent secondary chromosomal abnormality in hematological diseases, the possibility of a genetic predisposition for these disorders in patients with 8q duplication is raised.

Gene expression differences in normal esophageal mucosa associated with regression and progression of mild and moderate squamous dysplasia in a high-risk Chinese population

A randomized, double-blinded, placebo-controlled 2 x 2 factorial chemoprevention trial was conducted in Linxian, China to assess the effects of selenomethionine and celecoxib on the natural history of esophageal squamous dysplasia. Results from this study indicated that asymptomatic adults with mild dysplasia were more likely to show an improvement when treated with selenomethionine compared with placebo (P = 0.02). Prompted by this finding, we examined the molecular profiles associated with regression and progression of dysplastic lesions in normal mucosa from 29 individuals, a subset of the Linxian cohort, using the Affymetrix U133A chip. Twenty differentially expressed genes were associated with regression and 129 were associated with progression when we compared the change in gene expression over time. Genes associated with immune response (n = 15), cell cycle (n = 15), metabolism (n = 15), calcium transport or calcium ion activity (n = 10), regulation of transcription (n = 9), signal transduction (n = 7), cytoskeleton and microtubules (n = 5), nucleotide processing and biosynthesis (n = 4), G-coupled signaling (n = 4), and apoptosis (n = 3) were present in the list of 149 genes. Using the Expression Analysis Systematic Explorer pathway analysis program, only the immune response pathway was significantly overrepresented among these 149 genes. Individuals whose lesions regressed seemed to have higher expression of genes associated with immune stimulation, such as antigen presentation, survival of T cells, and T-cell activation (HLA-DRA, HLA-DPA1, HLA-DBQ1, CD58, and FCER1A). In contrast, individuals whose lesions progressed had higher expression of genes involved in immune suppression and inflammation (CNR2, NFATC4, NFRKB, MBP, INHBB, CMKLR1, CRP, ORMS, SERPINA7, and SERPINA1). These data suggest that local and systemic immune responses may influence the natural history of esophageal squamous dysplasia.

The 11q terminal deletion disorder: a prospective study of 110 cases

We performed a prospective study of 110 patients (75 not previously published) with the 11q terminal deletion disorder (previously called Jacobsen syndrome), diagnosed by karyotype. All the patients have multiple dysmorphic features. Nearly all the patients (94%) have Paris-Trousseau syndrome characterized by thrombocytopenia and platelet dysfunction. In total, 56% of the patients have serious congenital heart defects. Cognitive function ranged from normal intelligence to moderate mental retardation. Nearly half of the patients have mild mental retardation with a characteristic neuropsychiatric profile demonstrating near normal receptive language ability, but mild to moderate impairment in expressive language. Ophthalmologic, gastrointestinal, and genitourinary problems were common, as were gross and fine motor delays. Infections of the upper respiratory system were common, but no life-threatening infections were reported. We include a molecular analysis of the deletion breakpoints in 65 patients, from which genetic "critical regions" for 14 clinical phenotypes are defined, as well as for the neuropsychiatric profiles. Based on these findings, we provide a comprehensive set of recommendations for the clinical management of patients with the 11q terminal deletion disorder.

A multiple translocation event in a patient with hexadactyly, facial dysmorphism, mental retardation and behaviour disorder characterised comprehensively by molecular cytogenetics. Case report and review of the literature

We report a 13-year-old female patient with multiple congenital abnormalities (microcephaly, facial dysmorphism, anteverted dysplastic ears and postaxial hexadactyly), mental retardation, and adipose-gigantism. Ultrasonography revealed no signs of a heart defect or renal abnormalities. She showed no speech development and suffered from a behavioural disorder. CNS abnormalities were excluded by cerebral MRI. Initial cytogenetic studies by Giemsa banding revealed an aberrant karyotype involving three chromosomes, t(2;4;11). By high resolution banding and multicolour fluoresence in-situ hybridisation (M-FISH, MCB), chromosome 1 was also found to be involved in the complex chromosomal aberrations, confirming the karyotype 46,XX,t(2;11;4).ish t(1;4;2;11)(q43;q21.1;p12-p13.1;p14.1). To the best of our knowledge no patient has been previously described with such a complex translocation involving 4 chromosomes. This case demonstrates that conventional chromosome banding techniques such as Giemsa banding are not always sufficient to characterise complex chromosomal abnormalities. Only by the additional utilisation of molecular cytogenetic techniques could the complexity of the present chromosomal rearrangements and the origin of the involved chromosomal material be detected. Further molecular genetic studies will be performed to clarify the chromosomal breakpoints potentially responsible for the observed clinical symptoms.

CONCLUSION

This report demonstrates that multicolour-fluorescence in-situ hybridisation studies should be performed in patients with congenital abnormalities and suspected aberrant karyotypes in addition to conventional Giemsa banding.