Sharon Abish

High Incidence of Vertebral Fractures in Children With Acute Lymphoblastic Leukemia 12 Months After the Initiation of Therapy

PURPOSE Vertebral fractures due to osteoporosis are a potential complication of childhood acute lymphoblastic leukemia (ALL). To date, the incidence of vertebral fractures during ALL treatment has not been reported. PATIENT AND METHODS We prospectively evaluated 155 children with ALL during the first 12 months of leukemia therapy. Lateral thoracolumbar spine radiographs were obtained at baseline and 12 months. Vertebral bodies were assessed for incident vertebral fractures using the Genant semiquantitative method, and relevant clinical indices such as spine bone mineral density (BMD), back pain, and the presence of vertebral fractures at baseline were analyzed for association with incident vertebral fractures. RESULTS Of the 155 children, 25 (16%; 95% CI, 11% to 23%) had a total of 61 incident vertebral fractures, of which 32 (52%) were moderate or severe. Thirteen (52%) of the 25 children with incident vertebral fractures also had fractures at baseline. Vertebral fractures at baseline increased the odds of an incident fracture at 12 months by an odds ratio of 7.3 (95% CI, 2.3 to 23.1; P = .001). In addition, for every one standard deviation reduction in spine BMD Z-score at baseline, there was 1.8-fold increased odds of incident vertebral fracture at 12 months (95% CI, 1.2 to 2.7; P = .006). CONCLUSION Children with ALL have a high incidence of vertebral fractures after 12 months of chemotherapy, and the presence of vertebral fractures and reductions in spine BMD Z-scores at baseline are highly associated clinical features.

Clinical and genetic analysis of unclassifiable inherited bone marrow failure syndromes.

OBJECTIVE. Unclassified inherited bone marrow failure syndromes are a heterogeneous group of genetic disorders that represent either new syndromes or atypical clinical courses of known inherited bone marrow failure syndromes. The relative prevalence of the unclassified inherited bone marrow failure syndromes and their characteristics and the clinical and economic challenges that they create have never been studied. METHODS. We analyzed cases of inherited bone marrow failure syndrome in the Canadian Inherited Marrow Failure Registry that were deemed unclassifiable at study entry. RESULTS. From October 2001 to March 2006, 39 of the 162 patients enrolled in the Canadian Inherited Marrow Failure Registry were registered as having unclassified inherited bone marrow failure syndromes. These patients presented at a significantly older age (median: 9 months) than the patients with classified inherited bone marrow failure syndrome (median: 1 month) and had substantial variation in the clinical presentations. The hematologic phenotype, however, was similar to the classified inherited bone marrow failure syndromes and included single- or multiple-lineage cytopenia, severe aplastic anemia, myelodysplasia, and malignancy. Grouping patients according to the affected blood cell lineage(s) and to the presence of associated physical malformations was not always sufficient to characterize a condition, because affected members from several families fit into different phenotypic groups. Compared with the classified inherited bone marrow failure syndromes, the patients with unclassified inherited bone marrow failure syndromes had 3.2 more specific diagnostic tests at 4.5 times higher cost per evaluated patient to attempt to categorize their syndrome. At last follow-up, only 20% of the unclassified inherited bone marrow failure syndromes were ultimately diagnosed with a specific syndrome on the basis of the development of new clinical findings or positive genetic tests. CONCLUSIONS. Unclassified inherited bone marrow failure syndromes are relatively common among the inherited bone marrow failure syndromes and present a major diagnostic and therapeutic dilemma.

Improving diagnostic precision, care and syndrome definitions using comprehensive next-generation sequencing for the inherited bone marrow failure syndromes

Background Phenotypic overlap among the inherited bone marrow failure syndromes (IBMFSs) frequently limits the ability to establish a diagnosis based solely on clinical features. >70 IBMFS genes have been identified, which often renders genetic testing prolonged and costly. Since correct diagnosis, treatment and cancer surveillance often depend on identifying the mutated gene, strategies that enable timely genotyping are essential. Methods To overcome these challenges, we developed a next-generation sequencing assay to analyse a panel of 72 known IBMFS genes. Cases fulfilling the clinical diagnostic criteria of an IBMFS but without identified causal genotypes were included. Results The assay was validated by detecting 52 variants previously found by Sanger sequencing. A total of 158 patients with unknown mutations were studied. Of 75 patients with known IBMFS categories (eg, Fanconi anaemia), 59% had causal mutations. Among 83 patients with unclassified IBMFSs, we found causal mutations and established the diagnosis in 18% of the patients. The assay detected mutant genes that had not previously been reported to be associated with the patient phenotypes. In other cases, the assay led to amendments of diagnoses. In 20% of genotype cases, the results indicated a cancer surveillance programme. Conclusions The novel assay is efficient, accurate and has a major impact on patient care.

Possible new variant of Nijmegen breakage syndrome

We report on a child with microcephaly, small facial and body size, and immune deficiency. The phenotype is consistent with Nijmegen breakage syndrome (NBS), with additional clinical manifestations and laboratory findings not reported heretofore. Most investigations, including the results of radiation-resistant DNA synthesis, concurred with the diagnosis of NBS. Cytogenetic analysis documented abnormalities in virtually all cells examined. Along with the high frequency of breaks and rearrangements of chromosomes 7 and 14, we found breakage and monosomies involving numerous other chromosomes. Because of some variation in the clinical presentation and some unusual cytogenetic findings, we suggest that our patient may represent a new variant of Nijmegen breakage syndrome.

Comparative analysis of Shwachman-Diamond syndrome to other inherited bone marrow failure syndromes and genotype–phenotype correlation

Hashmi SK, Allen C, Klaassen R, Fernandez CV, Yanofsky R, Shereck E, Champagne J, Silva M, Lipton JH, Brossard J, Samson Y, Abish S, Steele M, Ali K, Dower N, Athale U, Jardine L, Hand JP, Beyene J, Dror Y. Comparative analysis of Shwachman‐Diamond syndrome to other inherited bone marrow failure syndromes and genotype–phenotype correlation.

An intronic mutation in dkc1 in an infant with høyeraal-hreidarsson syndrome

Toni Pearson, Fiona Curtis, Ayman Al-Eyadhy, Salem Al-Tamemi, Bruce Mazer, Yigal Dror, Sharon Abish, Sherri Bale, John Compton, Reena Ray, Patrick Scott, and Vazken M. Der Kaloustian* The McGill Department of Pediatrics, The Montreal Children’s Hospital (MUHC), Montreal, Quebec, Canada Departments of Human Genetics and Medical Genetics, McGill University, McGill University Health Center, Montreal, Quebec, Canada Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada GeneDx., Inc, Gaithersburg, Maryland Clinical Biochemistry and Genetics Diagnostic Services of Manitoba, Winnipeg, Manitoba, Canada

The impact of category, cytopathology and cytogenetics on development and progression of clonal and malignant myeloid transformation in inherited bone marrow failure syndromes

Inherited bone marrow failure syndromes are a group of rare, heterogeneous genetic disorders with a risk of clonal and malignant myeloid transformation including clonal marrow cytogenetic abnormalities, myelodysplastic syndrome and acute myeloid leukemia. The clinical characteristics, risk classification, prognostic factors and outcome of clonal and malignant myeloid transformation associated with inherited bone marrow failure syndromes are largely unknown. The aims of this study were to determine the impact of category, cytopathology and cytogenetics, the three components of the “Category Cytology Cytogenetics” classification of pediatric myelodysplastic syndrome, on the outcome of clonal and malignant myeloid transformation associated with inherited bone marrow failure. We used data from the Canadian Inherited Marrow Failure Registry. Among 327 patients with inherited bone marrow failure syndrome enrolled in the registry, the estimated risk of clonal and malignant myeloid transformation by the age of 18 years was 37%. The risk of clonal and malignant myeloid transformation varied according to the type of inherited bone marrow failure syndrome but was highest in Fanconi anemia. The development of clonal and malignant myeloid transformation significantly affected overall survival. Mortality varied based on cytopathological group. The largest group of patients had refractory cytopenia. Clonal marrow cytogenetic abnormalities were identified in 87% of patients with clonal and malignant myeloid transformation, and different cytogenetic groups had different impacts on disease progression. We conclude that category, cytopathology and cytogenetics in cases of clonal and malignant myeloid transformation associated with inherited bone marrow failure syndromes have an important impact on outcome and that the classification of such cases should incorporate these factors.

Primary Hyperparathyroidism Mimicking Vaso-occlusive Crises in Sickle Cell Disease

We report a case of bone pain associated with primary hyperparathyroidism in a patient with sickle cell disease. A 17-year-old girl with sickle cell disease (SS phenotype) was seen for bilateral knee and back pain. She had had recurrent severe vaso-occlusive crises and acute chest syndrome in the course of her disease. In the last 2 years, she had frequent visits to the emergency department for severe bone pain. She complained of long-standing fatigue and lethargy. Her physical examination was normal. Hydroxyurea treatment, as well as and long- and short-acting narcotics were given, with little improvement in symptoms. Poor compliance with medication, family dysfunction, and potential narcotic addiction were felt to be significant contributors to the patients symptoms. She was incidentally found to have an extremely elevated total calcium level of 3.19 mmol/L (range: 2.25–2.76) with an ionized calcium level of 1.9 mmol/L (range: 1.15–1.35). Phosphorus level was 0.82 mmol/L (range: 0.90–1.50), alkaline phosphatase level was elevated at 519 U/L (range: 10–170), and parathyroid hormone level was extremely high at 1645 pg/mL (range: 10–60). Her renal function was normal. Ultrasonography of the neck and a Sestamibi scan revealed a single left inferior parathyroid adenoma adjacent to the thyroid lobe. There was no evidence of an underlying multiple endocrine neoplasia. The patient was diagnosed with primary hyperparathyroidism. Fluid hydration, hydrocortisone, calcitonin, and bisphosphonates were initiated for acute hypercalcemia management before surgical excision of the left parathyroid adenoma. On review of previous blood work, a borderline calcium level of 2.72 was present 18 months before this admission. Two years postsurgery, she has normal renal function, calcium, and parathyroid hormone levels. The weekly visits to the emergency department for pain episodes decreased to 1 every 2 months within the first few months after her surgery. The decrease in pain episodes, even if it coincided with the treatment of primary hyperparathyroidism, may still reflect the natural evolution of sickle cell disease in this patient. However, the high morbidity associated with primary hyperparathyroidism was successfully prevented in this patient. Primary hyperparathyroidism is rare in childhood. In a recent study, it occurred more commonly in female adolescents and was because of a single adenoma, as in our patient. Significant morbidity, mainly secondary to renal dysfunction, was because of the delay in diagnosis after the onset of symptoms (2.0–4.2 years), emphasizing the need for a rapid diagnosis. Sickle cell disease affects ∼1 of every 600 blacks in North America. Acute episodes of severe vaso-occlusive crisis account for >90% of sickle cell-related hospitalizations and are a significant cause of morbidity in patients. There is no known association between sickle cell disease and primary hyperparathyroidism, and this case is most probably a random occurrence. However, as emphasized by this case report, pain may also be a harbinger of other disease processes in sickle cell disease. Because management may vary, we suggest that care providers consider the diagnosis of vaso-occlusive crisis as the diagnosis of exclusion and that other etiologies for pain be envisaged in this patient population, especially in the presence of prolonged pain or unusual clinical, radiologic, or biological findings.

Increased requirement for central venous catheter replacement in paediatric oncology patients with deep venous thrombosis: A multicentre study

Increased requirement for central venous catheter replacement in paediatric oncology patients with deep venous thrombosis: A multicentre study -

Exploring the Attitudes of Pediatric Oncologists Toward the Use of Laxatives for the Prevention of Constipation in Patients Undergoing Active Treatment: A Canadian Perspective

Background: Constipation is a common problem in pediatric oncology patients and may lead to significant consequences. There is a paucity of the published literature on the prevention of constipation in this population. The primary purpose of this study was to explore the current practice of pediatric oncologists in preventing constipation in children receiving active chemotherapy treatment, specifically during periods of intensive vincristine therapy. Methods: A Web-based survey of pediatric oncologists and pediatric oncology trainees in Canadian centers was conducted. Results: A 48% response rate was achieved. The majority of physicians had a lower threshold for defining constipation in oncology patients compared with the published literature. More than 90% of the respondents estimated the prevalence of constipation in pediatric oncology patients to be 30% or higher. The majority of respondents prescribed constipation prophylaxis in the presence of one or more of the following factors: history of constipation prior to or during previous phases of therapy, vincristine combined with either narcotics or immobility, multiple vincristine doses per month, spinal cord compression and immobility, and isolated narcotic therapy. Polyethylene glycol 3350, lactulose, and ducosate were the most commonly recommended first-line prophylactic therapies used. Conclusion: Constipation is a significant problem in patients during cancer treatment. Most oncologists suggest giving laxatives as prophylaxis in the presence of risk factors, as well as prompt treatment once any symptoms appear. Our results suggest a role for the introduction of guidelines in the prevention of constipation, especially for patients receiving frequent vincristine therapy.