Novel manifestations of immune dysregulation and granule defects in gray platelet syndrome.

Gray platelet syndrome (GPS) is a rare recessive disorder caused by biallelic variants in NBEAL2 and characterized by bleeding symptoms, the absence of platelet α-granules, splenomegaly, and bone marrow (BM) fibrosis. Due to the rarity of GPS, it has been difficult to fully understand the pathogenic processes that lead to these clinical sequelae. To discern the spectrum of pathologic features, we performed a detailed clinical genotypic and phenotypic study of 47 patients with GPS and identified 32 new etiologic variants in NBEAL2. The GPS patient cohort exhibited known phenotypes, including macrothrombocytopenia, BM fibrosis, megakaryocyte emperipolesis of neutrophils, splenomegaly, and elevated serum vitamin B12 levels. Novel clinical phenotypes were also observed, including reduced leukocyte counts and increased presence of autoimmune disease and positive autoantibodies. There were widespread differences in the transcriptome and proteome of GPS platelets, neutrophils, monocytes, and CD4 lymphocytes. Proteins less abundant in these cells were enriched for constituents of granules, supporting a role for Nbeal2 in the function of these organelles across a wide range of blood cells. Proteomic analysis of GPS plasma showed increased levels of proteins associated with inflammation and immune response. One-quarter of plasma proteins increased in GPS are known to be synthesized outside of hematopoietic cells, predominantly in the liver. In summary, our data show that, in addition to the well-described platelet defects in GPS, there are immune defects. The abnormal immune cells may be the drivers of systemic abnormalities such as autoimmune disease.

Treatment of transfusion-dependent congenital dyserythropoietic anemia Type I patients with pegylated interferon alpha-2a.

OBJECTIVE: Pegylated IFN-α2a has been reported in two case reports as being efficacious in treating CDA-I patients. This study aims to assess its efficacy on a series of CDA-I patients. METHODS: Study sample consisted of seven CDA type 1 transfusion-dependent patients. They received pegylated interferon alpha-2a at an initial dose of 90-180 µg once a week, tapered according to clinical response and side effects. Good response was defined as Hb ≥ 10 g/dL for ≥3 months, partial response was defined as 7 ≤ Hb<10 g/dL for ≥3 months, and no response was defined as HB < 7 g/dL for over 3 months on treatment. Time to response was defined as the time needed to achieve hemoglobin levels ≥ 10 g/dL without transfusion. Patients were evaluated periodically by abdominal ultrasounds to rule out liver adenomas. RESULTS: Five patients (71%) had a good response to treatment. One patient stopped treatment due to side effects. One patient had partial response. One patient, with more severe phenotype and poor compliance, had poor response to treatment. No abnormal findings were found in ultrasound examination. No effect on serum ferritin level could be established. CONCLUSION: Pegylated interferon α2a therapy is efficacious in CDA-I patients with a reasonable safety profile.

Inherited thrombocytopenia associated with mutation of UDP-galactose-4-epimerase (GALE).

Severe thrombocytopenia, characterized by dysplastic megakaryocytes and intracranial bleeding, was diagnosed in six individuals from a consanguineous kindred. Three of the individuals were successfully treated by bone marrow transplant. Whole-exome sequencing and homozygosity mapping of multiple family members, coupled with whole-genome sequencing to reveal shared non-coding variants, revealed one potentially functional variant segregating with thrombocytopenia under a recessive model: GALE p.R51W (c.C151T, NM_001127621). The mutation is extremely rare (allele frequency = 2.5 × 10-05), and the likelihood of the observed co-segregation occurring by chance is 1.2 × 10-06. GALE encodes UDP-galactose-4-epimerase, an enzyme of galactose metabolism and glycosylation responsible for two reversible reactions: interconversion of UDP-galactose with UDP-glucose and interconversion of UDP-N-acetylgalactosamine with UDP-N-acetylglucosamine. The mutation alters an amino acid residue that is conserved from yeast to humans. The variant protein has both significantly lower enzymatic activity for both interconversion reactions and highly significant thermal instability. Proper glycosylation is critical to normal hematopoiesis, in particular to megakaryocyte and platelet development, as reflected in the presence of thrombocytopenia in the context of congenital disorders of glycosylation. Mutations in GALE have not previously been associated with thrombocytopenia. Our results suggest that GALE p.R51W is inadequate for normal glycosylation and thereby may impair megakaryocyte and platelet development. If other mutations in GALE are shown to have similar consequences, this gene may be proven to play a critical role in hematopoiesis.

Morphological features of congenital dyserythropoietic anemia type I: The role of electron microscopy in diagnosis.

INTRODUCTION: Congenital dyserythropoietic anemias are rare blood disorders characterized by congenital anemia and a wide range of morphological and functional abnormalities of erythroid precursors. OBJECTIVES: To analyze the relative frequency of both light microscopic (LM) and electron microscopic (EM) morphological features of erythroblasts in a large group of patients with molecular proven congenital dyserythropoietic anemia type I (CDAI). METHODS: We retrospectively evaluated the LM and EM of bone marrow (BM) erythroblasts in 35 patients with CDAI. Thirty-four patients carried the CDAN1 Arg1042Trp founder mutation and one the p.Pro1130Leu mutation. BM slides of 24 patients were available for LM examination. EM studies were performed in all 35 patients. RESULTS: On LM, marked erythroid hyperplasia, binuclear erythroblasts, and various non-specific dyserythropoietic features were documented in every case; internuclear chromatin bridges were detected in 19 patients (79%). In all, EM of erythroblasts revealed a spongy appearance of heterochromatin, a widening of nuclear pores, and invagination of cytoplasm into the nuclear region. CONCLUSIONS: EM studies revealed high morphological frequency of specific ultrastructural changes in erythroblasts which facilitate prompt diagnosis of CDAI. Due to low specificity of BM LM findings, when BM EM is unavailable diagnostic approach should also include other inherited anemias.

Morbidity and mortality of adult patients with congenital dyserythropoietic anemia type I.

Congenital dyserythropoietic anemia type I (CDAI) is a rare autosomal recessive disease characterized by macrocytic anemia, ineffective erythropoiesis, and secondary hemochromatosis. To better define the natural history of the disease among adult patients, we studied 32 Bedouin patients (median age 34 yr; range 21-60) all carrying the same CDAN1 founder mutation. Follow-up studies included complete blood count, blood chemistry, abdominal ultrasound, echocardiography, and T2*MRI. Main complications were due to anemia and ineffective erythropoiesis [osteoporosis (8/9, 89%), cholelithiasis (21/30, 70%), pulmonary arterial hypertension (PAH) (6/25, 24%)] and iron overload [hypothyroidism (9/24, 38%), and diabetes mellitus (6/32, 19%)]. T2* MRI revealed increased liver iron but no cardiac iron (13/13). Anemia improved in the majority of patients who underwent splenectomy (5/6). Three patients died (9%) at the age of 46-56 due to PAH (1) and sepsis (2). All previously underwent splenectomy. Analyzing both our patients and the 21 patients previously described by Heimpel et al. (Blood 107:334, 2006), we conclude that adults with CDA I suffer significant morbidity and mortality. Careful monitoring of iron overload and prompt iron chelation therapy is mandatory. Due to possible complications and inconsistent response to splenectomy α-interferon, transfusion therapy or stem cell transplantation should be considered as alternatives to this procedure in severely affected patients.

Proton pump inhibitors use suppresses iron absorption in congenital dyserythropoietic anemia.

Congenital dyserythropoietic anemia type I (CDA I) is associated, as other anemic noninflammatory states, with ineffective erythropoiesis and increased iron absorption, which may lead to complication of iron overload. The latter complication requires iron-chelating therapy, which may be associated with adverse effects and toxicity. Gastric acid production is known to be an important factor that facilitates non-heme iron absorption. The purpose of this study was to examine whether treatment with proton pump inhibitors (PPIs) can decrease iron absorption in patients with CDA I. Eight CDA I patients (4 boys) aged 12-18 years with mild iron overload (not yet requiring chelating therapy) received 20 mg/d omeprazole for 6 months. Blood samples were obtained for ferritin, C-reactive protein, hemoglobin, calcium, and magnesium at baseline, at the end of months intervention and 6 months after its cessation. The mean ferritin level decreased from 585 ± 180 ng/ml at baseline to 522 ± 172 ng/ml at the end of 6-month treatment and 660 ± 256 ng/ml 6 months after cessation of omeprazole treatment (p  =  0.009). Omeprazole treatment caused a nonsignificant reduction in the mean iron level (iron 159 ± 42, 136 ± 54,167 ± 34 µg/dl, p  =  0.302). However, mean hemoglobin level was mildly but significantly reduced (Hg 10.0 ± 0.8, 9.55 ± 1.0, 10.4 ± 10.7 g/dl, p  =  0.002). No adverse effects were reported. Our investigation suggests that administration of PPI to patients with CDA I may reduce iron absorption and may lower iron overload and the need for chelation therapy.

Persistent pulmonary hypertension of the newborn associated with severe congenital anemia of various etiologies.

Among the many associated features of persistent pulmonary hypertension of the neonate (PPHN), severe congenital anemia has been described only occasionally and is not included in the list of conditions that may cause PPHN in the neonate. We describe the clinical course of a group of 12 full-term neonates with PPHN and congenital anemia due to congenital dyserythropoietic anemia (7/12), α thalasemia (1/12), Diamond-Blackfan (1/12), and epsilon gamma delta beta thalassemia (3/12). The association of congenital anemia and PPHN is more common than previously thought; it can exist with various etiologies and severity of anemia. Congenital anemia has not been described until now as a cause or risk factor for PPHN; it should be considered as such alone or in combination with other known causes to be recognized early and treated appropriately to improve outcome. In families with known cases of congenital anemia due to the above-mentioned diagnosis, closer prenatal follow-up should be offered to anticipate possible fetal distress and/or fetal anemia and PPHN after birth.

Normal hemoglobin at the age of 1 year does not protect infants from developing iron deficiency anemia in the second year of life.

BACKGROUND: Iron deficiency anemia (IDA) is the most common hematologic disorder worldwide. Measures to prevent IDA in infants have been successful with questionable sustainability. AIM: To evaluate the incidence of developing IDA in the second year of life, in infants who were nonanemic at the age of 1 year on routine blood test. METHODS: Blood samples were obtained from 193, 24-month-old toddlers, from 2 large clinics of both main sectors in Southern Israel, comparable for lower economic status. IDA was defined as hemoglobin < 11 gr% and microcytosis as mean corpuscular volume < 70 fL. RESULTS: IDA was detected in 8 of 118 Bedouins (5 males) and in 10 of 75 Jewish (6 males) infants (P < 0.01). The probability of a nonanemic child to develop IDA in the second year of life for the whole study population was 9.3% (18 of 193 infants) and significantly higher in the Jewish population (13.3.0% vs. 6.8%, P < 0.01). CONCLUSIONS: Given the difficulty of toddlers to maintain a non-IDA status, and the very low probability of iron overload, our results clearly support the need to continue iron supplementation into the second year.

[Childhood genetic renal diseases in southern Israel].

Genetic kidney diseases (GKDs) are an important and well-known entity in pediatric nephrology. Advances in genetic and molecular approaches in the last 15 years have enabled elucidation of the underlying molecular defects in many of these disorders. Herein, the authors summarize the progress that has been made over this period in disclosing the molecular basis of several novel GKDs which were characterized in this area and include Bartter syndrome type IV, type II Bartter syndrome and transient neonatal hyperkalemia, cystinuria and mental retardation, familial hypomagnesemia with secondary hypocalcemia, infantile nephronophthisis and familial hemolytic uremic syndrome with factor H deficiency. Retrospective analysis of the authors' data reveals that GKDs are over-represented among the pediatric population in southern Israel. GKD are seen 4 times more often than end-stage renal disease (ESRD) and comprise 38% of all cases of ESRD in our area. This high rate of GKD is mainly due to the high frequency of consanguineous marriages that prevails in this area. Understanding of the genetic and molecular background of these diseases is a result of a fruitful collaboration between the pediatric nephrologists and scientists, and has a direct implication on the diagnosis and treatment of the affected families.

Identification and characterization of the first mutation (Arg776Cys) in the C-terminal domain of the Human Molybdenum Cofactor Sulfurase (HMCS) associated with type II classical xanthinuria.

Classical xanthinuria type II is an autosomal recessive disorder characterized by deficiency of xanthine dehydrogenase and aldehyde oxidase activities due to lack of a common sulfido-olybdenum cofactor (MoCo). Two mutations, both in the N-terminal domain of the Human Molybdenum Cofactor Sulfurase (HMCS), were reported in patients with type II xanthinuria. Whereas the N-terminal domain of HMCS was demonstrated to have cysteine desulfurase activity, the C-terminal domain hypothetically transfers the sulfur to the MoCo. We describe the first mutation in the C-terminal domain of HMCS identified in a Bedouin-Arab child presenting with urolithiasis and in an asymptomatic Jewish female. Patients were diagnosed with type II xanthinuria by homozygosity mapping and/or allopurinol loading test. The Bedouin-Arab child was homozygous for a c.2326C>T (p.Arg776Cys) mutation, while the female patient was compound heterozygous for this and a novel c.1034insA (p.Gln347fsStop379) mutation in the N-terminal domain of HMCS. Cosegregation of the homozygous mutant genotype with hypouricemia and hypouricosuria was demonstrated in the Bedouin family. Haplotype analysis indicated that p.Arg776Cys is a recurrent mutation. Arg776 together with six surrounding amino acid residues were found fully conserved and predicted to be buried in homologous eukaryotic MoCo sulfurases. Moreover, Arg776 is conserved in a diversity of eukaryotic and prokaryotic proteins that posses a domain homologous to the C-terminal domain of HMCS. Our findings suggest that Arg776 is essential for a core structure of the C-terminal domain of the HMCS and identification of a mutation at this site may contribute clarifying the mechanism of MoCo sulfuration.

Familial steroid-sensitive nephrotic syndrome in Southern Israel: clinical and genetic observations.

Reports on genetically informative steroid-responsive (sensitive) idiopathic nephrotic syndrome (SSNS) families are lacking. We studied an extended SSNS Bedouin (B) family with a high rate of consanguinity. The clinical presentation and steroid response of its 11 affected individuals were similar to those of sporadic SSNS (spontaneous remission towards puberty and minimal change disease by kidney biopsy). Genome-wide linkage analysis, using a 382 microsatellite-markers mapping set and additional markers adjacent to 80 candidate genes of the index family, did not support linkage to any chromosomal locus. Retrospective analysis of all additional children with SSNS treated by our institution in the past 20 years (n=96, 50% of them of Jewish origin) revealed another five non-related B families with 2-3 first-degree cousins affected with SSNS in each. The overall familial SSNS rate among the B population (excluding the index family) was 28%, compared with 4% among Jews (Js) (OR 1.8-64, P<0.005). There were more Bs with simple SSNS than there were Js (71% and 40%, respectively; OR 3.58, 95% CI 1.41-9.23, P<0.01). In summary, SSNS in this index family was not linked to any of the presently known chromosomal loci nor predicted to be caused by mutation in any one of a list of genes associated with nephrotic syndrome (NS). The presence of other B families affected by SSNS supports the role for susceptibility genes enrichment, exposing highly consanguineous populations to an increased incidence of SSNS.

Transient severe metastatic calcification in acute renal failure.

Metastatic calcification, a known complication of prolonged end-stage renal disease, is herein described for the first time in a 10-month-old boy with acute renal failure, manifesting as a painful and swollen arm. Imaging revealed diffuse calcification and technetium-99 methylene diphosphonate (99Tc-MDP) uptake around the humerus and axilla. Calcium and vitamin D restriction, followed by intravenous administration of sodium thiosulfate caused a full symptomatic, radio- and scintigraphic improvement.

Genetic kidney diseases in the pediatric population of southern Israel.

Genetic kidney diseases (GKDs) are an important and well-known entity in pediatric nephrology. In the past decade advances in genetic and molecular approaches have enabled elucidation of the underlying molecular defects in many of these disorders. Herein we summarize the progress that has been made over the past decade in disclosing the molecular basis of several novel GKDs, which were characterized in our area and include Bartter syndrome type IV, type II Bartter syndrome and transient neonatal hyperkalemia, cystinuria and mental retardation, familial hypomagnesemia with secondary hypocalcemia, infantile nephronophthisis, familial hemolytic uremic syndrome with factor H deficiency, and non-cystic autosomal dominant nephropathy. Retrospective analysis of our data reveals that GKDs are over-represented among the pediatric population in southern Israel. GKDs are seen four-times more often than end-stage renal disease (ESRD) and comprise 38% of all cases of ESRD in our area. This high rate of GKDs is mainly due to the high frequency of consanguineous marriages that prevails in this area. Understanding of the genetic and molecular background of these diseases is a result of a fruitful collaboration between the pediatric nephrologists and scientists, and has a direct implication on the diagnosis and treatment of the affected families.

A comprehensive study of the neonatal manifestations of congenital dyserythropoietic anemia type I.

Congenital dyserythropoietic anemia (CDA) type I is an inherited disorder characterized by macrocytic anemia with pathognomonic morphologic ultrastructural features of the erythroid precursors. The authors recently cloned the CDAN1 gene and identified one founder missense mutation in all of their Bedouin patients. In a previous study, the authors found that the majority of their 31 Bedouin patients had anemia and jaundice during the first month of life and required blood transfusions; some had persistent pulmonary hypertension. In the present retrospective evaluation of 70 Bedouin patients with CDA type I, the authors more than doubled the number. Forty-five (64%) patients were symptomatic in the neonatal period, 29 (65%) had hepatomegaly, 24 (53%) had early jaundice, 11 (27%) were born small for gestational age, 7 (15%) had persistent pulmonary hypertension, and 6 (13%) had direct hyperbilirubinemia and another 6 (13%) had transient thrombocytopenia. Thirty-six of the symptomatic neonates (80%) required at least one blood transfusion. These results confirm the authors' previous findings and add neonatal manifestations not previously described, particularly hyperbilirubinemia and thrombocytopenia. Early diagnosis of CDA type I may be beneficial in light of the potential efficacy of alpha-interferon in avoiding transfusions in some patients.

Congenital dyserythropoietic anemia type I is caused by mutations in codanin-1.

Congenital dyserythropoietic anemias (CDAs) constitute a rare group of inherited red-blood-cell disorders associated with dysplastic changes in late erythroid precursors. CDA type I (CDAI [MIM 224120], gene symbol CDAN1) is characterized by erythroid pathological features such as internuclear chromatin bridges, spongy heterochromatin, and invagination of the nuclear membrane, carrying cytoplasmic organelles into the nucleus. A cluster of 45 highly inbred Israeli Bedouin with CDAI enabled the mapping of the CDAN1 disease gene to a 2-Mb interval, now refined to 1.2 Mb, containing 15 candidate genes on human chromosome 15q15 (Tamary et al. 1998). After the characterization and exclusion of 13 of these genes, we identified the CDAN1 gene through 12 different mutations in 9 families with CDAI. This 28-exon gene, which is transcribed ubiquitously into 4738 nt mRNA, was reconstructed on the basis of gene prediction and homology searches. It encodes codanin-1, a putative o-glycosylated protein of 1,226 amino acids, with no obvious transmembrane domains. Codanin-1 has a 150-residue amino-terminal domain with sequence similarity to collagens and two shorter segments that show weak similarities to the microtubule-associated proteins, MAP1B (neuraxin) and synapsin. These findings, and the cellular phenotype, suggest that codanin-1 may be involved in nuclear envelope integrity, conceivably related to microtubule attachments. The specific mechanisms by which codanin-1 underlies normal erythropoiesis remain to be elucidated.