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1/131. Elective bone marrow transplantation in a child with X-linked hyper-IgM syndrome presenting with acute respiratory distress syndrome.

    We describe a 10-month-old boy diagnosed with X-linked hyper-IgM syndrome (XHIM) after suffering from life-threatening acute respiratory distress syndrome (ARDS) caused by pneumocystis carinii pneumonia (PCP), although his previous clinical history and first level laboratory tests investigating immunological function did not indicate immunodeficiency. When the patient's overall condition was good, elective bone marrow transplantation from an HLA-matched older brother was performed successfully. We describe how correct diagnosis and successful treatment were made possible thanks to the involvement of a network of specialists. ( info)

2/131. X-linked thrombocytopenia in a girl.

    We report X-linked thrombocytopenia (XLT) in a 6-year-old girl with petechiae and thrombocytopenia from the age of 3 months. Her 2-year-old brother was also diagnosed with XLT. The wiskott-aldrich syndrome protein (WASP) gene was detected as a replacement of 5th G to Aon intron 6 using sequence analysis, and the WASP expression levels in this patient were one-third those of a healthy control. The X-inactivation analysis of the patients lymphocytes showed a random pattern of X-chromosome inactivation. To our knowledge, this is the first confirmed report of XLT in a female. ( info)

3/131. Absent phenotypic expression of X-linked sideroblastic anemia in one of 2 brothers with a novel ALAS2 mutation.

    X-linked sideroblastic anemia (XLSA) is caused by mutations in the erythroid-specific 5-aminolevulinic acid synthase (ALAS2) gene. Hemizygous males have microcytic anemia and iron overload. A 38-year-old male presented with this phenotype (hemoglobin [Hb] 7.6 g/dL, mean corpuscular volume [MCV] 64 fL, serum ferritin 859 microg/L), and molecular analysis of ALAS2 showed a mutation 1731G>A predicting an Arg560His amino acid change. A 36-year-old brother was hemizygous for this mutation and expressed the mutated ALAS2 mRNA in his reticulocytes, but showed almost no phenotypic expression. All 5 heterozygous females from this family, including the 3 daughters of the nonanemic hemizygous male, showed marginally increased red-cell distribution width (RDW). Although variable penetrance for XLSA in males has been previously described, this is the first report showing that phenotypic expression can be absent in hemizygous males. This observation is relevant to genetic counseling, emphasizing the importance of gene-based diagnosis. ( info)

4/131. Two brothers with keratosis follicularis spinulosa decalvans.

    keratosis follicularis spinulosa decalvans is a rare, X-linked disorder affecting both the skin and eyes. There are few reports about this entity. The aim of this report is to describe 2 brothers with progressive scarring alopecia of the scalp, hypotrichosis with follicular prominence of the eyelashes, and extensive keratosis pilaris. The second patient has down syndrome with palmoplantar keratoderma and partial alopecia of the eyebrows. We also reviewed the literature about this uncommon entity. ( info)

5/131. pregnancy outcome following prenatal diagnosis of an isodicentric x chromosome: first case report.

    An isodicentric x chromosome, idic (X)(q27) was found in a female fetus during cytogenetic studies performed on amniotic cells due to advanced maternal age. No mosaicism was observed. Although segmental inversion duplications have been described for several other chromosomes, isodicentric chromosomes are reported only for gonosomes. Genetic counselling was based on ultrasound findings, cytogenetic replication studies and published cases of X chromosomes duplications ascertained pre- and postnatally. The pregnancy resulted in the birth of a healthy female infant. ( info)

6/131. von Recklinghausen disease in a patient with X-linked agammaglobulinemia.

    A 33-year-old man was referred to our hospital because of intractable cellulitis in his left lower leg. He was diagnosed with agammaglobulinemia at the age of 6 years and had been receiving gamma-globulin supplementation since then. Laboratory examination revealed a markedly reduced number of B cells, decreased protein amount of Bruton's tyrosine kinase (BTK) in monocytes, and a single base substitution of C994-->T(missense mutation of Arg288-->Trp) in BTK gene, confirming the diagnosis of X-linked agammaglobulinemia (XLA). The patient also had characteristic features of von Recklinghausen disease, such as numerous subcutaneous nodules, cafe-au-lait spots, Lisch nodules in the iris and spinal scoliosis. biopsy of a subcutaneous nodule confirmed a neurofibroma. Although the influence of XLA on the development of von Recklinghausen disease is unknown for the moment, this is, to our knowledge, the first report of a patient with XLA who also developed von Recklinghausen disease. ( info)

7/131. X-linked myotubular myopathy with probable germline mosaicism.

    X-linked myotubular myopathy is a disorder characterized by severe neonatal hypotonia and respiratory insufficiency. The mutation of MTMI gene results in a defective production of myotubularin, which is responsible for the maturational arrest of muscle development. An identical mutation in the carrier mother and the diseased child establishes the inheritance. We report the disease in a neonate with a mutation on exon 6 of the MTMI gene. Surprisingly, the mother was healthy and did not carry this mutation, she is likely to have germline mosaicism. ( info)

8/131. A novel mutation in the G4.5 (TAZ) gene in a kindred with barth syndrome.

    barth syndrome is an X-linked recessive disorder characterised by dilated cardiomyopathy and a variable expression of skeletal myopathy, short statue and neutropenia. Molecular genetic analysis is currently the most reliable diagnostic method. A kindred with a novel 535delC mutation in the G4.5 (TAZ) gene responsible for barth syndrome is presented. Beside the patient, the same mutation was detected in patient's mother and grandmother. In contrast to the so far reported patients with mutations in the same region of G4.5 (TAZ) gene, the patient described here has only a mild and transitory clinical presentation. This could be attributed to alternative splicing of G4.5 (TAZ) gene, since mRNA lacking exon 6 (with 535delC mutation) was detected. Genetic analysis of the G4.5 (TAZ) gene was helpful for establishing the precise diagnosis of barth syndrome and for adequate genetic counselling. Predicting the phenotype on the basis of mutations is unreliable especially if mutations are localised in alternatively spliced exons of the G4.5 (TAZ) gene which may result in a milder clinical presentation than expected. ( info)

9/131. Late-onset X-linked sideroblastic anemia following hemodialysis.

    X-linked sideroblastic anemia (XLSA) is due to deficient activity of erythroid-specific 5-aminolevulinate synthase (ALAS2). We report here a patient who developed sideroblastic anemia at the age of 81 years while undergoing hemodialysis. The diagnosis of sideroblastic anemia was established by the presence of ringed sideroblasts in the bone marrow, and treatment with oral pyridoxine completely eliminated the ringed sideroblasts. We identified a novel point mutation in the fifth exon of this patient's ALAS2 gene, which resulted in an amino acid change at residue 159 from aspartic acid to asparagine (Asp159Asn). in vitro analyses of recombinant Asp159Asn ALAS2 revealed that this mutation accounted for the pyridoxine-responsiveness of this disease. The very late onset in this case of XLSA emphasizes that nutritional deficiencies caused either by dietary irregularities in the elderly or, as in this case, by maintenance hemodialysis therapy, may uncover occult inherited enzymatic deficiencies in the heme biosynthetic pathway. ( info)

10/131. X-linked charcot-marie-tooth disease caused by a novel point mutation in the connexin-32 gene.

    We report the clinical and electrophysiological findings of a patient with X-linked charcot-marie-tooth disease and a novel point mutation in the connexin-32 gene. A 31-year-old man presented with a 5 year history of progressive imbalance and distal weakness in his legs. Electrophysiological studies confirmed an asymmetric, predominantly axonal sensorimotor neuropathy with some demyelinating features. genetic testing revealed a G/A transition (Ala40Thr) in a conserved transmembrane region of the connexin-32 gene. ( info)
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