Multifocal Lymphangioendotheliomatosis with Thrombocytopenia: Presentation of Two Cases Treated with Sirolimus.

Multifocal lymphangioendotheliomatosis with thrombocytopenia (MLT) is a rare disease characterized by congenital and progressive vascular lesions of the skin and gastrointestinal tract that may be associated with thrombocytopenia and possibly life-threatening gastrointestinal bleeding. Reports published on the disease and treatment strategies are scarce. We present two cases of MLT treated with sirolimus.

Novel TMPRSS6 mutations associated with iron-refractory iron deficiency anemia (IRIDA).

Mutations leading to abrogation of matriptase-2 proteolytic activity in humans are associated with an iron-refractory iron deficiency anemia (IRIDA) due to elevated hepcidin levels. In this paper we describe 12 IRIDA patients belonging to 7 unrelated families and identify 10 (9 novel) TMPRSS6 mutations spread along the gene sequence: 5 missense, 1 non sense and 4 frameshift. The frameshift and non sense mutations are predict to result in truncated protein lacking the catalytic domain. The causal role of missense mutations (Y141C, I212T, R271Q, S304L and C510S) is demonstrated by in silico analysis, their absence in 100 control chromosomes and the high conservation of the involved residues. The C510S mutation in the LDLRA domain in silico model causes an intra-molecular structural imbalance that impairs matriptase-2 activation. We also assessed the in vitro effect on hepcidin promoter and the proteolytic activity of I212T and R271Q variants demonstrating a reduced inhibitory effect for the former mutation, but surprisingly a normal function for R271Q which appears a silent mutation in vitro. Based on mRNA expression studies I212T could also decrease the total amount of protein produced, likely interfering with mRNA stability. Collectively, our results extend the pattern of TMPRSS6 mutations associated with IRIDA and propose a model of causality for some of the novel missense mutation.

[Beta thalassemia major in Argentina]. / Beta talasemia mayor en la Argentina.

An analysis of beta thalassemia major patients seen at Hospital Juan P. Garrahan was carried out in order to determine the characteristics and outcome of the population. From August 1987 to July 2000, 45 patients were admitted (27 males-18 females). The most common beta globin gene defects were C-39 (30.7%); IVS-I nt 110 (20%); IVS-I nt 6 (13.3%); IVS-I nt 1(4%). alpha globin genes were normal in 42 patients, 1 patient had triplicate and cuadriplicate alpha globin genes and 2 patients were not analyzed. Six patients of 5 families were heterozygous for -158G gamma mutation. Allogeneic stem cell transplantation was performed in 7 patients, with an identical sibling. Transfusion-related infections and alloantibodies were detected in 6.7% patients. Growth assessment showed no significant difference in the stature of girls compared to the reference population, but 5 boys had short stature. There is a tendency to short trunk. Growth velocity was normal at prepubertal age. No X-ray lesions related to desferrioxamine were observed. Delayed puberty and hypogonadotropic hypogonadism were found in 35.7% and abnormalities in GH/IGF-I axis in 12.5% of the patients. Impaired glucose tolerance was found in 2 patients. No patient developed diabetes mellitus, thyroid or adrenal insufficiency. One patient had cardiac complications. Forty-two patients are alive and 3 died (cardiac failure 1, central nervous system bleeding 1, sepsis 1). We conclude that beta thalassemia major, originated mainly from Italian immigrants, has a cumbersome treatment and is severely hindered by the lack of adequate economic resources in our patients.

Management of transfusional iron overload in Latin America: current outlook and expert panel recommendations.

The results of a meeting of physicians convening in Latin America to develop expert opinions on the diagnosis, monitoring and treatment of iron overload are as follows. An accurate diagnosis can be obtained by neonatal screening for haemoglobinopathies, especially sickle cell disease and the thalassaemias. Disease-specific registries are needed to demonstrate the extent of the problem to health authorities. Disparities in the quantity and quality of blood products must be addressed, and uniform transfusion guidelines are necessary. Serum ferritin level is a feasible marker for iron overload in the region, while magnetic resonance imaging assessment can improve the diagnosis and monitoring of cardiac and liver iron content. Medical specialists, including radiologists, pathologists and others, and health authorities, can help to implement these methods and provide adequate resources. The recently available oral deferasirox can be used to conveniently administer iron chelation to transfusional iron-overloaded patients.

ATR-16 due to a de novo complex rearrangement of chromosome 16.

We describe a child with ATR-16 [alpha-thalassemia (thal)/mental retardation], who was referred for genetic evaluation because of minor anomalies and developmental delay. Cytogenetic analysis demonstrated a de novo complex rearrangement of chromosome 16. Fluorescence in situ hybridization (FISH) analysis, using chromosome 16 subtelomeric probes, showed that this patient had a deletion of the distal short arm of chromosome 16 that contains the alpha-globin genes and a duplication of 16q. Analysis of the alpha-globin locus by Southern blot showed a half normal dose of the alpha-globin gene. Microsatellite marker studies revealed that the duplicated 16q region was maternal in origin. Hematological studies revealed anemia, hypochromia and occasional cells with Hb H inclusion bodies. A hematological screening for alpha-thal should be considered in patients with mild developmental delay and a suggestive phenotype of ATR-16 with microcytic hypochromic anemia and normal iron status. The stellate pattern of the iris, a new finding in our patient, may contribute to a better clinical delineation of both syndromes, ATR-16 and/or duplication of 16qter.

Beta talasemia mayor en la Argentina / [Beta thalassemia major in Argentina]

An analysis of beta thalassemia major patients seen at Hospital Juan P. Garrahan was carried out in order to determine the characteristics and outcome of the population. From August 1987 to July 2000, 45 patients were admitted (27 males-18 females). The most common beta globin gene defects were C-39 (30.7

). alpha globin genes were normal in 42 patients, 1 patient had triplicate and cuadriplicate alpha globin genes and 2 patients were not analyzed. Six patients of 5 families were heterozygous for -158G gamma mutation. Allogeneic stem cell transplantation was performed in 7 patients, with an identical sibling. Transfusion-related infections and alloantibodies were detected in 6.7

patients. Growth assessment showed no significant difference in the stature of girls compared to the reference population, but 5 boys had short stature. There is a tendency to short trunk. Growth velocity was normal at prepubertal age. No X-ray lesions related to desferrioxamine were observed. Delayed puberty and hypogonadotropic hypogonadism were found in 35.7

and abnormalities in GH/IGF-I axis in 12.5

of the patients. Impaired glucose tolerance was found in 2 patients. No patient developed diabetes mellitus, thyroid or adrenal insufficiency. One patient had cardiac complications. Forty-two patients are alive and 3 died (cardiac failure 1, central nervous system bleeding 1, sepsis 1). We conclude that beta thalassemia major, originated mainly from Italian immigrants, has a cumbersome treatment and is severely hindered by the lack of adequate economic resources in our patients.