Mark Micale

Mutations in CEP57 cause mosaic variegated aneuploidy syndrome

Using exome sequencing and a variant prioritization strategy that focuses on loss-of-function variants, we identified biallelic, loss-of-function CEP57 mutations as a cause of constitutional mosaic aneuploidies. CEP57 is a centrosomal protein and is involved in nucleating and stabilizing microtubules. Our findings indicate that these and/or additional functions of CEP57 are crucial for maintaining correct chromosomal number during cell division.

Langerhans/dendritic cell sarcoma arising from hairy cell leukemia: a rare phenomenon.

Dear Editor, A 66-year-old female was diagnosed in 2000 with hairy cell leukemia (HCL). Flow cytometry from her bone marrow biopsy (BMB) demonstrated a monotypic B cell population expressing CD11c, CD22, CD25, and CD103. She was successfully treated with cladribine [1]; however, in 2003, she relapsed, and BMB showed a monotypic B cell population. Cytogenetic analysis revealed an abnormal hyperdiploid karyotype in 2 of 20 metaphase cells: 48,XX,+4,del(6)(q23), del(8)(p21)x2,+12,del(14)(q24), add(17)(p13) (Fig. 1). She was again treated with cladribine and rituximab [2]. In 2008, imaging revealed splenomegaly. Splenectomywas performed, and pathology showed HCL. BMB revealed extensive involvement by a monotypic B cell population negative for CD5, CD10, CD103, and CD25. This phenotype was the same as reported on previous BMB, but differed in that it was CD25 and CD103 negative. Five months later, the patient presented with a left pyriform sinus mass (SUV of 32.8 on PET scan) which was biopsied (Fig. 2). BMB revealed involvement by the previously diagnosed HCL with a monoclonal B cell population demonstrating a phenotype similar to that observed in previous studies. Based on histologic and immunophenotypic findings, this tumor was classified as Langerhans/dendritic cell sarcoma (L/DCS) (expression S100, CD1a; negative for B and T cell markers and CD30). Cytogenetic evaluation identified the hyperdiploid complex karyotype: 47,XX,+4,del(6)(q23),del(8)(p21)x2,+12, -13,del(14)(q24),add(17)(p13). This karyotype and the one obtained in 2003 BMB positive for HCL were essentially identical, although L/DCS presented with monosomy 13. In addition, clonal immunoglobulin gene rearrangements identified by polymerase chain reaction from both specimens were also identical. Combined, cytogenetic, and immunoglobulin gene rearrangement studies suggest that both the HCL and L/DCS developed from the same precursor cells. The patient was treated with three cycles of gemcitabine and docetaxel [3]. However, due to significant progression, the patient opted for hospice. Clinical data have shown that two hematopoietic populations in the same patient may share identical genetic changes or abnormalities, raising the possibility that tumors expressing the phenotype of one hematopoietic lineage might “transdifferentiate” into a genetically similar but phenotypically distinct tumor of a different lineage [4]. Histiocytic/dendritic cell sarcomas (H/DCS) arising from follicular lymphoma (FL) have been reported earlier (eight patients) [5]. In six of these patients, both lesions possessed the same genetic aberration, namely the FL-associated IGH/BCL2 gene rearrangement associated with the t(14;18)(q32;q21). The remaining two demonstrated identical BCL2/JH or clonal IGH gene rearrangements or both. Based on these observations, the authors suggested a clonal relationship between FL and H/DCS. Feldman et al. also demonstrated a common clonal origin in a patient with acute lymphoblastic leukemia and subsequent histiocytic sarcoma, based on identical IGH and TCRγ gene rearrangements in both lesions [6]. Zhang et al. described a Electronic supplementary material The online version of this article (doi:10.1007/s00277-011-1399-5) contains supplementary material, which is available to authorized users. A. Muslimani :M. M. Chisti (*) : I. Boxwala : I. Jaiyesimi Department of Hematology and Oncology, Oakland University William Beaumont School of Medicine, William Beaumont Hospital, 3577 W 13 Mile Rd, Suite 202, Royal Oak, MI 48073, USA e-mail: mohsinchisti@yahoo.com

Mosaic variegated aneuploidy without microcephaly: Implications for cytogenetic diagnosis

Mosaic variegated aneuploidy (MVA) is a rare condition characterized by multiple trisomies, rarely monosomies, and a non‐specific phenotype including microcephaly, growth and mental retardation, mild malformations, and an increased risk of malignancy. We describe a patient with MVA in whom trisomy 19 mosaicism was originally suspected. The patient was the product of an uncomplicated term pregnancy and delivery. Significant findings were mental retardation, obesity, mild epicanthal folds, tapering fingers, relatively small hands and feet, alternating exotropia, nasal speech limited to short phrases, and generalized hypotonia. There is no family history for birth defects, mental retardation, or consanguinity. The initial peripheral blood chromosome study showed trisomy 19 in 4 of 31 metaphase cells. Because mosaic trisomy 19 is rare, the study was extended to 100 cells, wherein two cells with trisomy 8 were identified. A second blood karyotype was obtained and found to be 47,XX,+8[3]/47,XX,+19[3]/47,XX, +18[2]/47,XX,+9[1]/46,XX[91]. Skin fibroblast chromosome studies revealed a 46,XX karyotype in 120 cells examined. There was no evidence of premature centromere separation. Mutations in the BUB1B gene that encodes a key mitotic spindle checkpoint protein have been described in MVA; however, no mutations of this gene were identified in our patient. This case illustrates the importance of considering other possibilities when confronted with an extremely rare diagnosis such as mosaic trisomy 19. In addition, it shows the importance of not simply interpreting a low percentage of multiple aneuploidies as cell culture artifact, because an additional work‐up to rule out MVA may be warranted since this diagnosis is associated with an increased risk of malignancy.

Pulmonary infiltrates in acute myeloid leukemia during induction treatment: how much do we know?

Background:During induction treatment, acute myeloid leukemia patients may develop pulmonary infiltrates due to infectious or noninfectious etiologies. The risk association and the clinical outcome of such pulmonary infiltrates are poorly characterized in the literature. Methods:We retrospectively reviewed 363 cases of acute myeloid leukemia patients who received induction therapy as inpatients over a period of 11 years at William Beaumont Health System. Of these 363 patients, 120 developed pulmonary infiltrates during induction therapy, those patients were divided into 2 groups based on distribution of the infiltrate presenting as localized or diffuse in nature. Data on patients characteristics, leukemia subtype, cytogenetic risk, microorganism type, white blood cell count at diagnosis, neutrophil count at the time the infiltrate was reported, response to antibiotic and/or antifungal therapy, using respiratory support, and mortality rate were retrieved through chart review. Results:Thirty-three percent of patients developed pulmonary infiltrates during their induction therapy. Sixty-three patients (52.5%) had a localized infiltrates and 57 patients (47.5%) had diffuse infiltrates. Of the 120 patients with pulmonary infiltrates, 48 (40%) had at least 1 pathogenic microorganism identified, and 58 (48.7%) required intubation and ventilatory support. Patients with localized pulmonary infiltrates were more likely to have positive pathogenic microorganisms (68.3% vs. 8.8%, P<0.001), to be neutropenic (96.8% vs. 21%, P<0.001), and tended to have potentially reversible infiltrates after treatment (87.3% vs. 21%, P<0.001). Whereas patients with diffuse infiltrates were more like to require intubation (78.9% vs. 21%, P<0.001), to have leukocytosis (white blood cell >100 billions/L) at diagnosis (54.4% vs. 0%, P<0.001), and had a higher mortality rate (70.2% vs. 9.5%, P<0.001). Conclusions:The radiologic patterns of pulmonary infiltrates showed specific etiological and prognostic associations. Diffuse infiltrates are an unfavorable characteristic with overall dismal outcome.

Macrocerebellum, epilepsy, intellectual disability, and gut malrotation in a child with a 16q24.1-q24.2 contiguous gene deletion

Macrocerebellum is a rare condition characterized by enlargement of the cerebellum with conservation of the overall shape and cytoarchitecture. Here, we report on a child with a distinctive constellation of clinical features including macrocerebellum, epilepsy, apparent intellectual disability, dysautonomia, gut malrotation, and poor gut motility. Oligonucleotide chromosome microarray analysis identified a 16q24.1–q24.2 deletion that included four OMIM genes (FBXO31, MAP1LC3B, JPH3, and SLC7A5). Review of prior studies describing individuals with similar or overlapping16q24.1–q24.2 deletions identified no other reports of macrocerebellum. These observations highlight a potential genetic cause of this rare disorder and raise the possibility that one or more gene(s) in the 16q24.1–q24.2 interval regulate cerebellar development.

Prenatal identification of two discontinuous maternally inherited chromosome 7q36.3 microduplications totaling 507 kb including the sonic hedgehog gene in a fetus with multiple congenital anomalies

Duplications of the SHH gene, an important developmental gene, are rare. Disruption of this gene produces a variable phenotype in humans from major anomalies to isolated facial defects. This is the first reported case of a maternally inherited 507 kb discontinuous chromosome 7q36.3 microduplication resulting in duplication of SHH and nearby enhancer sequences.

Secondary acute myelogenous leukemia (AML) with trisomy 10 and del(9q) following precursor B-cell acute lymphoblastic leukemia (ALL) with a hyperdiploid karyotype

Acute myelogenous leukemia (AML) secondary to acute lymphoblastic leukemia (ALL) in children is uncommon and usually occurs within 10 years of completing therapy for ALL. A variety of recurrent cytogenetic abnormalities have been described, suggesting significant biological heterogeneity. We report a case of highly refractory secondary AML with trisomy 10 and del(9q) occurring in an adolescent female 12 years after she was treated successfully for precursor B-cell ALL with chemotherapy only.