1/38. 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.- - - - - - - - - - ranking = 1keywords = dent (Clic here for more details about this article) |
2/38. 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.- - - - - - - - - - ranking = 1keywords = dent (Clic here for more details about this article) |
3/38. Hypohydrotic ectodermal dysplasia: an unusual presentation and management in an 11-year-old Xhosa boy.ectodermal dysplasia (ED) is an inherited disorder in which two or more ectodermally derived structures fail to develop, or are abnormal in development. Hypohydrotic ectodermal dysplasia (HED) or Christ-Siemens-Touraine syndrome, is an X-linked recessive syndrome with an incidence of 1/10,000 to 1/100,000 births. Because of its X-linked inheritance pattern, it is more common in males. HED is characterised by hypohydrosis (diminished perspiration), hypotrichosis (decreased amount of hair) and microdontia (small teeth), hypodontia (lack of development of one or more teeth) or adontia (total lack of tooth development). These patients present diagnostic and treatment challenges because of variable oral manifestations. This report describes an 11-year-old Xhosa boy, who was referred to the University Dental faculty by his general medical practitioner because of hypodontia. General facial features included: frontal bossing, a depressed nasal bridge, 'butterfly' pattern of eczema over the nasal bridge to the malar process of each cheek, thinned out hair, loss of vertical dimension of face and dry skin. Intra-oral examination revealed hypodontia with peg-shaped anterior teeth and diastemas. Radiological examination revealed no developing permanent teeth or tooth buds. diagnosis was confirmed by doing a sweat gland count. Management included oral hygiene instruction, fluoride treatments, construction of a partial lower denture and counselling about his condition with particular reference to the danger of hyperthermia and control of allergies.- - - - - - - - - - ranking = 1keywords = dent (Clic here for more details about this article) |
4/38. A novel CACNA1F mutation in a french family with the incomplete type of X-linked congenital stationary night blindness.PURPOSE: To describe a French family with the incomplete type of X-linked congenital stationary night blindness (CSNB2) associated with a novel mutation in the retina-specific calcium channel alpha(1) subunit gene (CACNA1F). DESIGN: Interventional case report. methods: Two family members with a history of nonprogressive night blindness and subnormal visual acuity were clinically examined and the genotype determined by molecular genetic analysis. RESULT: Both patients had clinical manifestations characteristic of CSNB2. Electrophysiologically, we found a predominant reduction of the ERG B-wave in the maximal response. Both rod and cone function were subnormal, with the latter tending to be more attenuated. We identified a C deletion at nucleotide position 4548, resulting in a frameshift with a predicted premature termination at codon 1524. CONCLUSIONS: The clinical and genetic study of a novel mutation in the CACNA1F gene adds further support to the contention that CSNB2 represents a genetically distinct retinal disorder of a calcium channel.- - - - - - - - - - ranking = 1keywords = dent (Clic here for more details about this article) |
5/38. Disruption of the serine/threonine kinase 9 gene causes severe X-linked infantile spasms and mental retardation.X-linked West syndrome, also called "X-linked infantile spasms" (ISSX), is characterized by early-onset generalized seizures, hypsarrhythmia, and mental retardation. Recently, we have shown that the majority of the X-linked families with infantile spasms carry mutations in the aristaless-related homeobox gene (ARX), which maps to the Xp21.3-p22.1 interval, and that the clinical picture in these patients can vary from mild mental retardation to severe ISSX with additional neurological abnormalities. Here, we report a study of two severely affected female patients with apparently de novo balanced X;autosome translocations, both disrupting the serine-threonine kinase 9 (STK9) gene, which maps distal to ARX in the Xp22.3 region. We show that STK9 is subject to X-inactivation in normal female somatic cells and is functionally absent in the two patients, because of preferential inactivation of the normal X. Disruption of the same gene in two unrelated patients who have identical phenotypes (consisting of early-onset severe infantile spasms, profound global developmental arrest, hypsarrhythmia, and severe mental retardation) strongly suggests that lack of functional STK9 protein causes severe ISSX and that STK9 is a second X-chromosomal locus for this disorder.- - - - - - - - - - ranking = 1keywords = dent (Clic here for more details about this article) |
6/38. X-linked myotubular myopathy in a family with three adult survivors.We describe a family with an extremely mild form of X-linked myotubular myopathy. Three affected males survived to adulthood with sufficient muscle strength to enable them to carry out normal daily activities. The mildness of the myopathy in this family is highlighted by the following: no neonatal or infant mortality resulting from the myopathy; one affected male who did not have neonatal asphyxia and had normal early motor milestones - this affected male was able to increase his muscle bulk and strength to normal by weightlifting; and a 55-year-old male who still lives an independent life. dna sequencing identified a novel missense mutation - G469A (E157K) - in exon 7 of the MTM1 gene in this family. To our knowledge, this is the third X-linked myotubular myopathy family, with multiple adult survivors, to be reported in the literature.- - - - - - - - - - ranking = 2keywords = dent (Clic here for more details about this article) |
7/38. A frameshift mutation of the ED1 gene in sibling cases with X-linked hypohidrotic ectodermal dysplasia.X-linked hypohidrotic ectodermal dysplasia (XLHED; MIM 305100) is characterized by the absence or hypoplasia of hair, teeth, and sweat glands. The ED1 gene was identified as a responsive gene for XLHED. The patients were 2 Japanese brothers. Both had the same mutation in exon 1 of the ED1 gene, i.e. C deletion at nucleotide 49, which induced a frameshift starting from amino acid 17 and made a stop codon at amino acid 56, encoding the transmembrane site. The mutation caused the extracellular domain of ectodysplasin A to be completely absent. Their mother had a heterozygous allele; she congenitally lacked 1 tooth, and incisors appeared conical in form.- - - - - - - - - - ranking = 1keywords = dent (Clic here for more details about this article) |
8/38. Complete recovery from cryptosporidium parvum infection with gastroenteritis and sclerosing cholangitis after successful bone marrow transplantation in two brothers with X-linked hyper-IgM syndrome.We describe two brothers who suffered from hyper-IgM syndrome (HIGM1) with similar clinical features: recurrent infections, especially cryptosporidium gastroenteritis with cholangitis. Their activated T cells did not express CD40L. Nucleotide sequencing revealed a mutation in both boys with respect to intron 4 and exon 5 boundaries of the CD40L gene in Xq26. They underwent successful bone marrow transplantation (BMT) from HLA-geno-identical siblings. The Cryptosporidium infection and cholangitis resolved thereafter. At 6 months after BMT, expression of CD40L on activated T lymphocytes was normal. After 1 year, both boys are well, and immune reconstitution has improved. Based on these two successful experiences, BMT with a genoidentical sibling seems a reasonable therapeutic approach for HIGM1, if Cryptosporidium infection occurs.- - - - - - - - - - ranking = 2keywords = dent (Clic here for more details about this article) |
9/38. A new X-linked syndrome with agenesis of the corpus callosum, mental retardation, coloboma, micrognathia, and a mutation in the Alpha 4 gene at Xq13.We describe two brothers with a unique pattern of malformations that includes coloboma (iris, optic nerve), high forehead, severe retrognathia, mental retardation, and agenesis of the corpus callosum (ACC). Both boys have low-set cupped ears with sensorineural hearing loss, normal phallus, pectus excavatum, scoliosis, and short stature. One brother had choanal atresia and cardiac defects consisting of ventricular septal defect (VSD) and patent ductus arteriosus (PDA) which resolved spontaneously. Differential diagnosis between a number of clinical entities was considered, however, because ACC and the distinctive facial features were reminiscent of FG syndrome, dna was analyzed for markers linked to the FGS1 locus at Xq13-q21. Notably, the brothers were concordant for markers spanning this presumed FG region, and in both we have identified adjacent alterations (-57delT and T-55A) in the Alpha 4 gene located within this interval. Alpha 4 is a regulatory subunit of the major cellular phosphatase, PP2A, that has recently been shown to interact with MID1, the product of the gene mutated in X-linked Opitz GBBB syndrome. The double nucleotide change identified in this family was not observed in 410 control chromosomes, suggesting that it may be a pathogenetic change. Altered expression of Alpha 4, through either a change in translational efficiency, mRNA stability or splicing, could explain the clinical phenotype in these boys and the phenotypic overlap with Opitz GBBB syndrome.- - - - - - - - - - ranking = 2keywords = dent (Clic here for more details about this article) |
10/38. X-linked motor and sensory neuropathy with pyramidal signs and cerebral white matter lesions.We report two brothers with hereditary motor and sensory neuropathies and pyramidal signs. Electrophysiological evaluation revealed polyneuropathy and involvement of the central motor, somatosensory, and auditory pathways. brain magnetic resonance imaging studies showed diffuse white matter lesions, and sural nerve biopsy identified a reduction in the large myelinated nerve fibers. The patients' mother and sister exhibited similar, but milder neurologic findings suggesting that the genetic defect may be X-linked; however, a point mutation in the connexin 32 gene was negative.- - - - - - - - - - ranking = 1keywords = dent (Clic here for more details about this article) |
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