Shwachman's syndrome. A review of 21 cases

Successful allogeneic hematopoietic stem cell transplantation (HSCT) for Shwachman-Diamond syndrome

Shwachman-Diamond syndrome (SDS) is a rare genetic disorder characterized by pancreatic insufficiency, short stature, skeletal abnormalities and bone marrow dysfunction. Patients with SDS have varying degrees of marrow aplasia, which can be severe or progress to leukemic transformation. While allogeneic hematopoietic stem cell transplantation (HSCT) can be curative for the hematologic disturbances of SDS, a recent review of the literature reveals few survivors. Poor outcome with HSCT is often related to excessive cardiac and other organ toxicity from transplant preparative therapy. We describe two young children with SDS who developed aplastic anemia and subsequently underwent successful allografting using a non-cardiotoxic conditioning regimen. Case 1 received marrow from an HLA-identical sibling while case 2 received partially matched umbilical cord blood from an unrelated donor. Both patients are presently alive and well with sustained donor engraftment and excellent hematopoietic function at 36 and 22 months post-HSCT.

Childhood myeloid leukaemias

Childhood myeloid leukaemias are a diverse collection of conditions. Although many are also seen in adults, some are peculiar to childhood. In childhood AML, as in adults, cytogenetic abnormalities are associated with specific clinical features and define prognostic groups. In infants under 1 year with AML, the incidence of 11q23 abnormalities is particularly high. The finding of identical 11q23 breakpoints in infant leukaemia as in therapy-related leukaemias suggests a role for in utero exposure to topoisomerase II inhibitors. There are a number of constitutional disorders that predispose children to develop AML, usually with a preceding myelodysplastic phase. Monosomy (or deletion of the long arm) of chromosome 7 is the most frequent chromosome abnormality in the bone marrow of such patients. Abnormalities of chromosome 7 are also common cytogenetic findings in all morphological subgroups of childhood myelodysplasia, either as a primary abnormality or associated with disease progression.

Implications of mutations in hematopoietic growth factor receptor genes in congenital cytopenias

Mutations in the genes of hematopoietic growth factor receptors as a cause of congenital cytopenia, such as congenital amegakaryocytic thrombocytopenia (CAMT) or severe congenital neutropenia (CN), are discussed. There are striking differences in the relevance of receptor mutations in these diseases. CAMT is a rare disease characterized by severe hypomegakaryocytic thrombocytopenia during the first years of life that develops into pancytopenia in later childhood. In patients with CAMT, we found inherited mutations in c-mpl, the gene coding for the thrombopoietin receptor, in 8 out of 8 cases. The type of mutation seems to correlate with the clinical course seen in the patients. Functional studies demonstrated defective thrombopoietin (TPO) reactivity in hematopoietic progenitor cells and platelets in CAMT patients. CN is a group of hematopoietic disorders characterized by profound, absolute neutropenia due to a maturation arrest of myeloid progenitor cells. About 10% of all patients develop secondary MDS/leukemia. The malignant progression is associated with acquired nonsense mutations within the G-CSF receptor gene that lead to the truncation of the carboxy-terminal cytoplasmic domain of the receptor protein involved in maturation of myeloid progenitor cells. This seems to be one important step in leukemogenesis in CN patients. CAMT is caused by inherited mutations in c-mpl, the gene for the thrombopoietin receptor, which lead to reduced or absent reactivity to TPO. In contrast, mutations in the G-CSF receptor in CN are acquired and are most probably connected with progression of the neutropenia into MDS/leukemia as a result of a loss of differentiation signaling.

Shwachman-Diamond syndrome with exocrine pancreatic dysfunction and bone marrow failure maps to the centromeric region of chromosome 7

Shwachman-Diamond syndrome (SDS) is an autosomal recessive disorder characterized by exocrine pancreatic insufficiency and hematologic and skeletal abnormalities. A genomewide scan of families with SDS was terminated at approximately 50% completion, with the identification of chromosome 7 markers that showed linkage with the disease. Finer mapping revealed significant linkage across a broad interval that included the centromere. The maximum two-point LOD score was 8.7, with D7S473, at a recombination fraction of 0. The maximum multipoint LOD score was 10, in the interval between D7S499 and D7S482 (5.4 cM on the female map and 0 cM on the male map), a region delimited by recombinant events detected in affected children. Evidence from all 15 of the multiplex families analyzed provided support for the linkage, consistent with a single locus for SDS. However, the presence of several different mutations is suggested by the heterogeneity of disease-associated haplotypes in the candidate region.

A practical approach to evaluating and treating neutropenia in the neonatal intensive care unit

Neutropenia is a relatively common problem in the NICU, recognized in as many as 8% of patients at some time during their hospital stay. In most instances, neutropenia among NICU patients is of short duration and has little influence on outcome. In other cases it is prolonged and severe, and constitutes a serious antimicrobial defense deficiency. When a neonatologist discovers a low blood neutrophil count, choices must be made regarding further evaluation and treatment. The authors hope that the information provided in this article is useful in making these choices.

Emergence of an unusual bone marrow precursor B-cell population in fatal Shwachman-Diamond syndrome

The Shwachman-Diamond syndrome (SDS) is a rare congenital disorder for which inheritance by an autosomal recessive trait has been suggested. Shwachman-Diamond syndrome is defined by exocrine pancreatic insufficiency combined with severe neutropenia. Moreover, SDS patients are at risk to develop neoplastic hematologic diseases. We describe 2 SDS-affected daughters of consanguine parents who were born 1 year apart, at 35 and 36 weeks of gestation, and who died at the age of 4 and 3.5 months, respectively, due to respiratory infections. Histologic bone marrow evaluation of the second-born child revealed a diffuse proliferation of immature B cells, which comprised 40% of the total cellularity. These cells were identified as precursor B cells by immunophenotyping studies (CD79a(+)/CD10(+)/CD20(-)/CD22(-)/CD34(-)/ terminal deoxynucleotidyl transferase(-)). Molecular determination of the immunoglobulin heavy-chain gene status did not reveal clonality. The emergence of this peculiar B-cell population was interpreted as a marked increase of hematogones. Although the clinical significance and the exact function of hematogones is still obscure, they may play a critical regenerative role in the regulation of hemopoiesis, but without malignant potential in SDS. Immunophenotyping and molecular studies, therefore, have potential value in the differential diagnosis of primary bone marrow failures. This report adds SDS to the spectrum of conditions in which a prominent number of hematogones may be observed.

Pancreatic aspects of cystic fibrosis and other inherited causes of pancreatic dysfunction

Causes of pancreatic dysfunction in childhood can be divided into two general categories: (1) hereditary conditions that directly affect the pancreas and (2) acquired disorders in which loss of pancreatic function is a secondary phenomenon. This article discusses genotypes and phenotypes, clinical features, Shwachman-Diamond syndrome, isolated enzyme deficiencies, and other topics.

Segregation analysis in Shwachman-Diamond syndrome: evidence for recessive inheritance

Shwachman-Diamond syndrome is a rare disorder of unknown cause. Reports have indicated the occurrence of affected siblings, but formal segregation analysis has not been performed. In families collected for genetic studies, the mean paternal age and mean difference in parental ages were found to be consistent with the general population. We determined estimates of segregation proportion in a cohort of 84 patients with complete sibship data under the assumption of complete ascertainment, using the Li and Mantel estimator, and of single ascertainment with the Davie modification. A third estimate was also computed with the expectation-maximization (EM) algorithm. All three estimates supported an autosomal recessive mode of inheritance, but complete ascertainment was found to be unlikely. Although there are no overt signs of disease in adult carriers (parents), the use of serum trypsinogen levels to indicate exocrine pancreatic dysfunction was evaluated as a potential measure for heterozygote expression. No consistent differences were found in levels between parents and a normal control population. Although genetic heterogeneity cannot be excluded, our results indicate that simulation and genetic analyses of Shwachman-Diamond syndrome should consider a recessive model of inheritance.

Discordant detection of monosomy 7 by GTG-banding and FISH in a patient with Shwachman-Diamond syndrome without evidence of myelodysplastic syndrome or acute myelogenous leukemia

The myelodysplastic syndromes (MDS) are a group of hematologic disorders commonly affecting elderly persons and often leading to acute myelogenous leukemia (AML). Although rare in children, when MDS does occur, it is frequently part of a congenital disorder such as Shwachman-Diamond syndrome (SDS). Monosomy 7 and/or deletion of part or all of 7q are poor prognostic signs in MDS and AML, although the pathophysiologic relationship between this finding and MDS or AML is unclear. Shwachman-Diamond syndrome is an inherited illness characterized by exocrine pancreatic insufficiency and by congenital neutropenia. Patients with SDS are at increased risk of developing myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). Because monosomy 7 is a poor prognostic sign in MDS and AML, establishing its presence is important. However, different methods of detection of monosomy 7 may lead to different results in some patients. We present the case of a 10-year-old girl known to have SDS, who had a bone marrow aspiration and biopsy done to rule out MDS and AML. By light microscopy, the patient's bone marrow was unremarkable. GTG-banding showed the following karyotype: 45,XX,-C[3]/47,XX,+C[1]/46,XX[45]. Fluorescence in situ hybridization (FISH) was performed with a chromosome 7-specific alpha-satellite probe (D7Z1). Almost all (373 of 376) cells exhibited only one chromosome 7 signal. A second marrow aspiration done 6 months later showed an essentially normal karyotype by GTG-banding. Fluorescence in situ hybridization with the same chromosome 7 probe showed 230 of 250 cells to be monosomic for chromosome 7. A whole chromosome 7 painting probe demonstrated disomy for chromosome 7 in 90 of 90 cells; however, subtle heteromorphism in the centromeric regions of the 2 copies of chromosome 7 was noted in some cells. This case demonstrates that FISH and GTG-banding can give discordant results, that the two should be viewed as complementary technologies, and that both have a place in a full karyotypic analysis. Furthermore, this case demonstrates for the first time that heteromorphism and/or subtle structural abnormalities of chromosome 7, previously associated with MDS and AML, can exist without clinical or morphologic signs of these illnesses. It will be of interest to further study the relationship, if any, between SDS and various structural abnormalities of chromosome 7 in MDS and AML, and to elucidate the molecular mechanisms of pathogenesis, physiology, and treatment of these disorders.

Shwachman's syndrome: pathomorphosis and long-term outcome

BACKGROUND

Shwachman's syndrome is the second most common cause of inherited/congenital pancreatic insufficiency after cystic fibrosis. The main associated features are usually cyclic neutropenia, metaphyseal dysostosis, and growth retardation. Other organs or functions may be involved in this syndrome, showing a wide range of abnormalities and symptoms. There are reports of Shwachman's syndrome in childhood, but little is known about the long-term clinical course of these patients. This article reports on the pathomorphosis and long-term follow-up of 13 patients with Shwachman's syndrome diagnosed in infancy focusing, in particular, on modifications of the exocrine pancreatic function over time.

METHODS

Exocrine pancreatic function was evaluated by duodenal intubation followed by a pancreatic stimulation test. Nutritional, biochemical, hematologic, radiologic, and psychological evaluations were performed at various intervals. Six patients were included in long-term follow-up evaluation.

RESULTS

At diagnosis, growth retardation was present in all patients, and all subjects showed pancreatic insufficiency. Hematologic features (intermittent neutropenia, anemia and thrombocytopenia), respiratory infection during the first years of life, and skeletal abnormalities were also frequently observed. Other associated features at diagnosis included hepatic involvement and occasional renal dysfunction. In the six patients followed up, a significant growth improvement was observed. In five of them the pancreatic stimulation test showed values of lipase within reference range outputs, whereas fat balance or fecal fat losses were normal in all but one subject. Of seven subjects assessed by psychological evaluation, IQ test results were markedly abnormal in one and bordered on abnormality in the others.

CONCLUSIONS

The present data on Shwachman's syndrome diagnosed in infancy underline the possibility of improvement or normalization of exocrine pancreatic function with age, suggesting the need for periodic checks on pancreatic activity in these subjects. It also indicates the possibility of diagnosis of this syndrome in the absence of pancreatic insufficiency; decreasing frequency of infections over time; and the usefulness of early neuropsychological evaluation.

Exclusion of linkage of Shwachman-Diamond syndrome to chromosome regions 6q and 12q implicated by a de novo translocation

Shwachman-Diamond syndrome is a rare genetic disorder of unknown pathogenesis involving exocrine pancreatic insufficiency and hematological and skeletal abnormalities. There is broad clinical variability; the extent of heterogeneity is unknown but comparisons within a large cohort of patients show no striking differences between patients of families with single or multiple affected offspring. Segregation analysis of a cohort of 69 families has suggested an autosomal recessive mode of inheritance. A single constitutional de novo chromosome rearrangement was reported in a Japanese patient involving a balanced translocation, t(6;12)(q16.2;q21.2), thereby suggesting possible loci for a genetic defect. Evenly spaced microsatellite markers spanning 26-32 cM intervals from D6S1056 to D6S304 and D12S375 to D12S346 were analyzed for linkage in members of 13 Shwachman-Diamond syndrome families with two or three affected children. Two-point lod scores were calculated for each marker under assumptions of recessive inheritance and complete penetrance. Negative lod scores indicated exclusion of both chromosome regions. Further, affected sibs were discordant for inheritance of chromosomes in most families based on constructed haplotypes. The cytogenetic abnormality is not associated with most cases of Shwachman-Diamond syndrome.

Shwachman syndrome: phenotypic manifestations of sibling sets and isolated cases in a large patient cohort are similar

OBJECTIVES

With the use of clinical data from a large international cohort, we evaluated and compared affected siblings and isolated cases.

STUDY DESIGN

Data from 116 families were collected, and patients conforming to our predetermined diagnostic criteria were analyzed. Phenotypic manifestations of affected siblings and singletons were compared with the use of t tests, Wilcoxon scores, and chi2 analysis.

RESULTS

Eighty-eight patients (33 female, 55 male; median age 5.20 years) fulfilled our predetermined diagnostic criteria for Shwachman syndrome; 63 patients were isolated cases, and 25 affected siblings were from 12 multiplex families. Steatorrhea was present in 86% (57 of 66), and 91% (78 of 86) displayed a low serum trypsinogen concentration. Patients older than 4 years more often had pancreatic sufficiency. Neutropenia occurred in 98%, anemia in 42%, and thrombocytopenia in 34%. Myelodysplasia or cytogenetic abnormalities were reported in 7 patients. Short stature with normal nutritional status was a prominent feature.

CONCLUSIONS

Clinical features among patients with Shwachman syndrome varied between patients and with age. Similarities in phenotype between isolated cases and affected sibling sets support the hypothesis that Shwachman syndrome is a single disease entity.

Cloning of translocation breakpoints associated with Shwachman syndrome and identification of a candidate gene

Shwachman syndrome is an autosomal-recessive disorder characterized by exocrine pancreatic insufficiency, bone-marrow dysfunction, and metaphyseal chondrodysplasia. A de novo balanced translocation was recently documented in a patient with this disease. Toward isolating the gene(s) responsible for Shwachman syndrome, we cloned and sequenced the translocation breakpoints in the DNA of this patient. The nucleotide sequences around the breakpoints contained neither repetitive elements nor motifs reported to be implicated in recombination events, although we did detect gains or losses of oligonucleotides at the translocation junctions. By large-scale genomic sequencing and in silico gene trapping, we identified two novel transcripts in the vicinity of the breakpoints that might represent candidate genes for Shwachman syndrome, one on chromosome 6 and the other on chromosome 12. The gene on chromosome 12 was actually disrupted by the translocation.

Pancreatic diseases (excluding cystic fibrosis)

Except for cystic fibrosis, which is the most frequent genetic disorder in the Caucasian population, diseases of the exocrine pancreas are relatively uncommon in children. However, they are many and varied in terms of their pathogenesis and clinical manifestation. They can be classified as: (1) congenital anatomical abnormalities, (2) congenital secretory insufficiencies, and (3) pancreatitis. In all of these diseases, when pancreatic insufficiency (whether partial or complete) is present, the nutritional status of the patients must be investigated regularly, and pancreatic enzymes as well as nutritional supplementations must be prescribed as soon as malnutrition is present, or even prophylactically. The preservation of good nutritional status is the guarantee of a better prognosis.

Pearson's syndrome without marrow involvement

A child with a mitochondrial DNA deletion who presented with pancreatic exocrine insufficiency is reported. Though she developed many other features of Pearson's syndrome, there was no bone marrow involvement. Syndromes associated with mitochondrial DNA defects are highly variable and absence of one feature should not inhibit investigation.

Immunodeficiency as a component of recognizable syndromes

Immunodeficiency occurs in numerous genetic syndromes. While it is the dominant manifestation in primary immunodeficiencies, immune deficits may also be seen in a variety of other recognizable syndromes. Immunodeficiency has been reported in 64 such conditions, adding to the 45 recognized primary immunodeficiencies. These uncommon syndromes with immune defects can present with: (a) growth deficiency (11 syndromes with disproportionate or proportionate short stature), (b) specific organ system dysfunction (18 with gastrointestinal, dermatologic, or neurologic abnormalities), (c) inborn errors of metabolism (13), (d) miscellaneous anomalies (10), or (e) chromosome anomalies (12). In most of the disorders, only some of the affected patients have immune defects. However, in 27 syndromes, immunodeficiency is a constant finding. We briefly review the clinical manifestations of each syndrome and delineate the specific associated immune defects. In most syndromes, the connection between the immune and other defects is unknown. Recognition of these conditions involving both the immune and other organ systems may facilitate accurate diagnosis and management as well as yield information regarding genes critical for the development of the involved systems.

Magnetic resonance imaging for diagnosis of Shwachman's syndrome

Shwachman's syndrome is a rare disease characterized by the association of chronic diarrhea due to exocrine pancreatic insufficiency, metaphyseal dysostosis, and neutropenia. The diagnosis requires demonstration of lipomatosis, or fatty replacement of the pancreas, which is the typical pathological feature of the disease. Magnetic resonance imaging (MRI) was performed in 13 patients with exocrine pancreatic insufficiency, 7 with Shwachman's syndrome, 2 with Pearson's syndrome, 1 with normal sweat test later diagnosed as cystic fibrosis, and 3 without identified syndrome, and in 7 control children. Ultrasonography in the patients did not differentiate between atrophy and lipomatosis and could not be performed in 3. MRI visualized the pancreas in all. The same image was noted in all patients with Shwachman's syndrome with a normal-sized or enlarged pancreas, a hyperintense signal on T1- and T2-weighted image, and a null signal on short time inversion recovery (STIR)-weighted image, characteristic of fat. In all other patients, the findings were very different: The pancreas was a small structure surrounded with fat. In 1 patient without identified syndrome, the pancreas appeared to be partially replaced with fat. MRI is an excellent imaging technique to correlate the nature of a tissue and its radiological representation, especially fat, which gives a very typical signal. In our brief series of patients with Shwachman's syndrome, MRI had 100% positive predictive value in demonstrating lipomatosis. In atypical cases of pancreatic insufficiency in which some of the clinical features of Shwachman's syndrome are absent. MRI is an invaluable aid in the diagnostic procedure.

Congenital Marrow Failure Syndromes and Malignant Hematopoietic Transformation

In the current era of advanced supportive care and administration of recombinant cytokines and other effective therapies, patients with congenital (inherited) marrow failure syndromes usually survive the early years of life and beyond. With the extended lifespan, a new “natural history” for these syndromes is evident. Although these disorders were always classified as “benign” historically, it is now evident that most of these conditions confer an inordinately high predisposition to myelodysplastic syndromes and acute myelogenous leukemia (MDS/AML). Since carcinogenesis occurs as a sequence of events that is driven by genetic damage and by epigenetic changes, the hypothesis is advanced that the first “hit” or leukemia-initiating step is the constitutional genetic mutation, itself, that initially manifests as a single lineage or multiple lineage marrow failure. The leukemic promotion and progression steps leading to MDS/AML can then ensue readily in the initiated pool of progenitors or stem cells. Thus, the distinction between benign and malignant hematology in the context of the inherited marrow failure disorders has become blurred and new definitions for these syndromes should be developed.

Severe Shwachman-Diamond syndrome and invasive parvovirus B19 infection

Parvovirus B19 (PVB19) is the causative agent of infectious erythema. In healthy children the virus causes transient erythroid aplasia, whereas in children with chronic hemolytic anemias it can cause severe aplastic crises, and in immunodeficient individuals it can produce chronic red cell aplasia. If contracted during pregnancy, the infection may induce serious damage to the fetus (abortion or hydrops fetalis). Shwachman-Diamond (S-D) syndrome, a rare autosomal recessive condition, consists of exocrine pancreatic insufficiency plus neutropenia; many patients develop either anemia or thrombocytopenia or both. We describe a newborn baby with severe congenital bone marrow failure who was diagnosed with S-D syndrome and persistence of PVB19 virus contracted by the mother in the third trimester of pregnancy.

Diagnosis and management of chronic neutropenia during childhood

The approach to the diagnostic evaluation of a patient with neutropenia can be guided largely by clinical history and physical examination and does not always require an extensive laboratory evaluation. Based on the history and bone marrow morphology, most children with chronic neutropenia can be classified and managed. Most patients with chronic neutropenia are free of infections and are able to maintain a normal lifestyle with no or minimal medical intervention. On the other hand, for patients with recurrent or severe infections, careful follow-up and institution of treatment are mandatory. The Food and Drug Administration has approved the use of rhG-CSF in patients with chronic neutropenia. As mentioned previously, the use of colony-stimulating factors has dramatically improved the outcome for many patients with the more severe neutropenia; however, this cytokine is expensive, so treatment should be reserved for more severely affected patients and not given just because the ANC is low. Although concerns exist regarding leukemogenic effects or eventual loss of the progenitor cell compartment driven by the continuous stimulation of rhG-CSF, at this moment, the long-term data available suggest that the chronic administration of rhG-CSF is safe.

Pancreatic diseases in children

The main congenital anomalies of the exocrine pancreas are reviewed, and several generalized and isolated hereditary pancreatic diseases are discussed. In contrast with adults, the most frequent causes of acute pancreatitis are viral infection, drug induction, and trauma. The dissimilarities between pediatric and acute and chronic pancreatitis are emphasized.

Shwachman syndrome associated with de novo reciprocal translocation t(6;12)(q16.2;q21.2)

We describe a de novo apparently balanced reciprocal translocation t(6;12)(q16.2; q21.2) in an 18 month old girl with Shwachman syndrome, characterised by exocrine pancreatic insufficiency and bone marrow dysfunction. The cause of this syndrome is unknown, although autosomal recessive inheritance has been proposed. The translocation breakpoints in the present patient may be candidate regions for a gene responsible for Shwachman syndrome.

An image processing procedure for the assessment of normality curves of motility of human granulocytes in micropore filters

With the conventional methods used in current practice, the results of human granulocyte motility assays are expressed by a numerical value that defines the leading front of cells into micropore filters. The authors have developed a fast procedure which allows the complete curve of polymorphonuclear leukocyte (PMN) migration to be obtained, from the initial plane of a filter to the maximum propagation depth. In this way, more information is given than that expressed by a single parameter. The paper describes the procedure used to determine the normality curves both for random and stimulated migration, according to a simple model which defines the PMN propagation in micropore filters. A normality band that defines variations due to the stochastic process is also reported.

Shwachman-Diamond syndrome: clinical, radiological and sonographic findings

Six children with Shwachman-Diamond syndrome have been diagnosed and treated in our hospital since 1986. We describe the radiological and sonographic findings of this rare disease, which is characterized by metaphyseal chondrodysplasia, neutropenia and exocrine pancreatic insufficiency. It presents with varying extremity shortening, "cup" deformation of the ribs, metaphyseal widening and hypoplasia of the iliac bones, as well as increased echogenicity of the normalized pancreas. We discuss the differential diagnosis and review the literature.

Shwachman-Diamond syndrome: clinical, radiological and sonographic aspects

Six children with Shwachman-Diamond syndrome have been diagnosed and treated in our hospital since 1986. We describe the radiological and sonographic findings of this rare disease which is characterized by metaphyseal chondrodysplasia, neutropenia and pancreatic exocrine insufficiency. It presents with variable extremity shortening, "cup" deformation of the ribs, metaphyseal widening and hypoplasia of the iliac bones, and increased echogenicity of the pancreas without change in size. We discuss the differential diagnosis and review the literature.

Acute leukemia complicating bone marrow hypoplasia in an adult with Shwachman's syndrome

Shwachman's syndrome is a rare congenital disorder associated with neutropenia and exocrine pancreatic insufficiency. We describe the development of acute myeloid leukemia in a 38-year-old patient with Shwachman's syndrome following three years of pancytopenia. After chemotherapy the leukemic clone was eradicated, however, the patient's bone-marrow hypoplasia persisted beyond 180 days with neutropenia that responded to administration of granulocyte colony-stimulating factor. Despite the patient's low erythropoietin levels, administration of erythropoietin did not improve his hemoglobin. We review previously reported cases of leukemia complicating Shwachman's syndrome with emphasis on the persistent risk of complications in patients with congenital bone-marrow failure syndromes.

Familial pancreatic enzyme insufficiency

A father and son with profound reduction of exocrine pancreatic activity and little visible pancreatic tissue on ultrasound or computed tomography are described. Both have some degree of liver disease, which is more marked in the son. The disorder, apparently familial, does not correspond to any reported previously.

Cartilage hair hypoplasia, metaphyseal chondrodysplasia type McKusick: description of seven patients and review of the literature

We describe 7 cases of cartilage hair hypoplasia (CHH) with emphasis on the clinical and immunological aspects. The literature on CHH is reviewed and symptoms in 63 non-Amish cases are summarized. In this autosomal recessive disorder the immunodeficiency, hair abnormalities, and severity of skeletal involvement show extremely variable expressivity, between and within families. Two of the 3 sib-pairs among our cases demonstrate the great difference in expression within one family. At adult age roentgenological abnormalities can be very mild, or even absent. An impairment in cell-mediated immunity is present in all of our cases and seems a consistent manifestation in CHH; however, sometimes it is very subtle and without clinical symptoms.

Chronic diarrhea. A practical approach for the pediatrician

Despite the high prevalence of chronic diarrhea there is no universal approach to its diagnosis and treatment. This article summarizes the pathophysiologic processes that result in chronic diarrhea and presents a diagnostic and therapeutic approach to this often distressing problem.

Increased whole blood chemiluminescence in patients with Shwachman syndrome: therapy trial with thiamine and alpha-tocopherol

Neutrophils purified from peripheral blood of patients with the Shwachman syndrome show enhanced chemiluminescence (CL) and depressed chemotaxis. Here we present data showing that the increased CL response can be demonstrated by using a whole blood CL assay. This assay is well-suited for studies in infants, because the blood sample volumes needed are small. Increase in CL was most distinct in the initial (1 min) activation induced by N-formyl-methionyl-leucyl-phenylalanine. The 1-min response is considered to derive from extracellular production of oxygen radicals. Such an extracellular oxygen radical production may render the patients susceptible to undue oxidant stress. We therefore treated the patients with two antioxidants, thiamine and alpha-tocopherol, for 3 months. This supplementation, however, failed to exert any significant effect on either whole blood CL or migration of the patients' neutrophils under agarose.

Psychological characteristics of children with Shwachman syndrome

Twelve children and young adults with Shwachman syndrome were compared with their unaffected siblings and with controls suffering from cystic fibrosis in terms of intellectual ability, motor skills, and behaviour. There were highly significant differences in intelligence quotient between those with Shwachman syndrome and the other two groups. Four of the index subjects but none of the control subjects were below the normal range. The differences between groups on other tests of cognitive and motor skills were not significant, though those with Shwachman syndrome tended to have the lowest scores. There was no evidence that those with Shwachman syndrome had more behavioural difficulties than the control subjects. We suggest that the intellectual difficulties of patients with Shwachman syndrome may be of neurological rather than social origin and that they may originate before birth.

Malabsorption of flucytosine in a pediatric patient with Shwachman syndrome

The malabsorption of drugs from the gastrointestinal tract in patients with pancreatic insufficiency is not well documented in the literature. We describe a case of flucytosine malabsorption in a pediatric patient with Shwachman syndrome, a rare disease in the pediatric age group characterized by pancreatic insufficiency. A significant increase in serum concentrations of flucytosine was noted when the drug was administered in a lipophilic vehicle, possibly due to enhanced absorption.

Nephrocalcinosis in Shwachman's syndrome

Nephrocalcinosis has been reported only infrequently in Shwachman's syndrome. We describe a case in which nephrocalcinosis occurred and speculate that this may be due to increased urinary oxalate excretion.

Immunoreactive trypsin in Shwachman's syndrome

We studied two infants with Shwachman's syndrome in whom the immunoreactive trypsin concentration was found to be abnormally low. Experience with several hundred assays for immunoreactive trypsin has not shown this low concentration. This finding is probably specific for pancreatic acinar deficiency at this age and strongly suggests Shwachman's syndrome.

Simplified oral pancreatic function test

The standard Bentiromide test and a new modified test using p-aminosalicylic acid (PAS) as a pharmacokinetic marker for p-aminobenzoic acid (PABA) have been evaluated in the detection of pancreatic exocrine insufficiency in children. The conventional two day test using a colorimetric assay for urinary PABA discriminated poorly between five children with pancreatic insufficiency and 13 others with normal pancreatic function. Two further groups of patients, comprising 28 with pancreatic exocrine insufficiency and 20 with normal pancreatic function underwent the modified test, and urine samples were analysed by high performance liquid chromatography. The results showed a complete separation between groups. The use of PAS eliminates a number of sources of error inherent in a two day Bentiromide test and provides a simplified and accurate diagnostic test for pancreatic insufficiency. The PABA-PAS modified test enables collection of the urine to be done during a single six hour period.