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11/20. X-linked hypophosphatemia: dental and histologic findings.

    The recurrent spontaneous formation of abscesses affecting multiple noncarious primary as well as permanent teeth is the principle clinical dental feature in cases of hypophosphatemia, a condition inherited through the x chromosome. patients often have high pulp horns, large pulp chambers and dentinal clefts. We report a case of hypophosphatemic vitamin d-resistant rickets in a patient who reported to our department on multiple occasions with spontaneous abscesses in relation to his primary teeth. The aim of this article is to review the features of this disorder and to discuss the risks and benefits of the treatment options suggested in the literature.
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ranking = 1
keywords = hypophosphatemic, rickets
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12/20. A novel mutation in EFNB1, probably with a dominant negative effect, underlying craniofrontonasal syndrome.

    Craniofrontonasal syndrome (CFNS) is an X-linked disorder whose main clinical manifestations include coronal craniosynostosis and frontonasal dysplasia. Very recently, CFNS was shown to be caused by mutations in EFNB1 encoding ephrin-b1, and 20 mutations have been described. We report a Thai woman with CFNS, in whom a novel mutation was discovered: c.685_686insG, in exon 5 of EFNB1. It is the first insertion and the most 3' point mutation in EFNB1 reported to date. The mutation is expected to result in a truncated ephrin-b1 of 230 amino acids, composed of a nearly complete extracellular part of ephrin-b1 with no transmembrane and cytoplasmic domains. This truncated protein might become a soluble form of the ligand, which previously was shown to be able to bind to receptors, but fail to cluster and to activate them--in other words, acting as a dominant negative protein. Nonetheless, further studies to detect the protein are needed to substantiate the hypothesis.
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ranking = 0.00013172453573607
keywords = dominant
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13/20. child syndrome in 3 generations: the importance of mild or minimal skin lesions.

    BACKGROUND: child syndrome (congenital hemidysplasia with ichthyosiform nevus and limb defects, Online Mendelian Inheritance in Man 308050) is an X-linked dominant trait with lethality for male embryos. The disorder is caused by mutations in NSDHL (Online Mendelian Inheritance in Man 300275), a gene playing an important role in the cholesterol biosynthetic pathway. Most reports deal with sporadic cases, and only 5 cases of mother-to-daughter transmission have been documented. We present here a family with mild features of child syndrome in 3 generations. Molecular analysis was used to confirm the diagnosis. OBSERVATIONS: We studied 14 members of a family with child syndrome. The 23-year-old proposita, her mother, 2 aunts, and her grandmother presented with mild or minimal skin lesions that had been present since infancy. Analysis of the NSDHL gene showed missense mutation c.370G-->A in these 5 patients. This mutation was absent in the 9 clinically unaffected family members tested. CONCLUSIONS: In this family, we recognized child syndrome with mild or minimal features in 3 generations because we were able to verify our clinical diagnosis by means of molecular analysis. We assume that many cases that so far have been considered sporadic may in fact be familial when a meticulous physical examination of female family members is combined with molecular testing.
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ranking = 2.6344907147214E-5
keywords = dominant
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14/20. Bilateral periventricular heterotopias in an X-linked dominant transmission in a family with two affected males.

    We report on the case of dizygotic twin boys, born prematurely to an asymptomatic mother. Bilateral periventricular heterotopias with enlarged ventricles were discovered at birth in both twins. One of the twins died prematurely of bronchopulmonary complications, and was shown to have several neuropathological anomalies (microgyria, thin corpus callosum, and reduced white matter). The surviving twin had mental retardation, without epilepsy. MRI of the mother showed asymptomatic periventricular heterotopias without ventricular enlargement. She had two affected daughters also with asymptomatic periventricular heterotopias. A point mutation in the last coding exon 48 of the Filamin A (FLNA) gene (7922c > t) was discovered on sequencing and segregated with the affected individuals. This family has a classical X-linked dominant BPNH pathology, with greater severity in males than females. The location of the FLNA mutation is discussed in light of the neuropathological anomalies and mental retardation in male patients.
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ranking = 0.00013172453573607
keywords = dominant
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15/20. Mechanistic associations of a mild phenotype of immunodysregulation, polyendocrinopathy, enteropathy, x-linked syndrome.

    BACKGROUND & AIMS: The syndrome of immunodysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is a rare disorder resulting in the expression of multiple autoimmune and allergic features. Early onset enteropathy and type 1 diabetes (T1D) are the most common clinical features. The IPEX syndrome is caused by mutations of the FOXP3 gene, which is essential for the development of regulatory T cells (Treg). We describe 2 unrelated patients with IPEX syndrome with a mild clinical phenotype and with novel FOXP3 mutations and the phenotypic and functional characterization of their Treg cells. methods: The FOXP3 gene was analyzed by sequencing amplimers from genomic dna. Treg cells were characterized by evaluating the number of CD4 CD25 T cells and their functional ability to suppress the proliferation of autologous CD4 CD25- effector T cells stimulated with anti-CD3 and anti-CD28 antibodies. RESULTS: A 7-year-old boy and a 24-year-old man presented with autoimmune enteropathy characterized by early onset persistent diarrhea not associated with T1D or other endocrinopathies. These 2 patients carry novel FOXP3 mutations that do not abrogate the function of the forkhead domain. They have normal numbers of CD4 CD25 T lymphocytes, however, these show severely defective suppressive function in vitro. CONCLUSIONS: Our 2 patients show that IPEX patients may present with early onset enteropathy and long-term survival without T1D or other endocrinopathies. This milder phenotype may be associated with FOXP3 mutations that do not abrogate the function of the forkhead domain.
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ranking = 2.6322961460478
keywords = x-linked
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16/20. blepharophimosis-mental retardation (BMR) syndromes: A proposed clinical classification of the so-called Ohdo syndrome, and delineation of two new BMR syndromes, one X-linked and one autosomal recessive.

    We report on 11 patients from 8 families with a blepharophimosis and mental retardation syndrome (BMRS) phenotype. Using current nosology, five sporadic patients have Ohdo syndrome, associated with congenital hypothyroidism in two of them (thus also compatible with a diagnosis of Young-Simpson syndrome). In two affected sibs with milder phenotype, compensated hypothyroidism was demonstrated. In another family, an affected boy was born to the unaffected sister of a previously reported patient. Finally, in the last sibship, two affected boys in addition had severe microcephaly and neurological anomalies. A definitive clinical and etiologic classification of BMRS is lacking, but closer phenotypic analysis should lead to a more useful appraisal of the BMRS phenotype. We suggest discontinuing the systematic use of the term "Ohdo syndrome" when referring to patients with BMRS. We propose a classification of BMRS into five groups: (1) del(3p) syndrome, (possibly overlooked in older reports); (2) BMRS, Ohdo type, limited to the original patients of Ohdo; (3) BMRS SBBYS (Say-Barber/Biesecker/Young-Simpson) type, with distinctive dysmorphic features and inconstant anomalies including heart defect, optic atrophy, deafness, hypoplastic teeth, cleft palate, joint limitations, and hypothyroidism. BMRS type SBBYS is probably an etiologically heterogeneous phenotype, as AD and apparently AR forms exist; (4) BMRS, MKB (Maat-Kievit-Brunner) type, with coarse, triangular face, which is probably sex-linked; (5) BMRS V (Verloes) type, a probable new type with severe microcephaly, hypsarrhythmia, adducted thumbs, cleft palate, and abnormal genitalia, which is likely autosomal recessive. Types MKB and V are newly described here.
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ranking = 0.65807403651195
keywords = x-linked
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17/20. De novo mutation in the BTK gene of atypical X-linked agammaglobulinemia in a patient with recurrent pyoderma.

    BACKGROUND: X-linked agammaglobulinemia (XLA), characterized by a profound deficiency of all immunoglobulins and the absence of mature B cells, is caused by mutations in the gene encoding Bruton tyrosine kinase (BTK). Most patients have recurrent sinopulmonary infection. Infections usually occur in multiple locations across time, but single infection may be limited to one anatomic location. OBJECTIVES: To report a case of atypical XLA with recurrent pyoderma and to observe the immunologic changes in the patient in 10 years. methods: Immunologic investigations, skin wound culture, and molecular study with dna sequencing were performed. RESULTS: The patient was originally diagnosed as having common variable immunodeficiency disease because of the presence of circulating B cells (CD19 B cells: 7%) at 11 years old. On further evaluation at the age of 20 years, flow cytometric analysis of lymphocytes showed only 0.4% B cells. The molecular study with dna sequencing of the patient showed a point mutation in complementary dna 1630 A>G(p.R544G) in the BTK gene, indicating that the patient has XLA. The mutation analysis of the BTK gene revealed a normal dna sequence in the other family members. CONCLUSIONS: This case is an important example of a possible presentation of XLA with a predominant skin manifestation, and it demonstrates that maintaining a high level of clinical suspicion is essential for the diagnosis of XLA in a child with recurrent pyoderma.
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ranking = 2.6344907147214E-5
keywords = dominant
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18/20. The high-resolution chest CT findings in an adult with Melnick-needles syndrome.

    Melnick-needles syndrome is an X-linked dominant skeletal dysplasia in which patients often succumb at an early age to chronic pulmonary disease. Radiographic findings of Melnick-needles syndrome consist of characteristic bony abnormalities and interstitial lung disease. We present the high-resolution computed tomographic (CT) findings in a 39-year-old survivor of Melnick-needles syndrome. The clinical and physical exam findings also demonstrate an association between Melnick-needles syndrome and obstructive sleep apnea.
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ranking = 2.6344907147214E-5
keywords = dominant
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19/20. A family with X-linked optic atrophy linked to the OPA2 locus Xp11.4-Xp11.2.

    Autosomal dominant optic atrophy (ADOA) is the most common inherited optic atrophy. Clinical features of ADOA include a slowly progressive bilateral loss of visual acuity, constriction of peripheral visual fields, central scotomas, and color vision abnormalities. Although ADOA is the most commonly inherited optic atrophy, autosomal recessive, X-linked, mitochondrial, and sporadic forms have also been reported. Four families with X-linked optic atrophy (XLOA) were previously described. One family was subsequently linked to Xp11.4-Xp11.2 (OPA2). This investigation studied one multi-generation family with an apparently X-linked form of optic atrophy and compared their clinical characteristics with those of the previously described families, and determined whether this family was linked to the same genetic locus. Fifteen individuals in a three-generation idaho family underwent complete eye examination, color vision testing, automated perimetry, and fundus photography. Polymorphic markers were used to genotype each individual and to determine linkage. Visual acuities ranged from 20/30 to 20/100. All affected subjects had significant optic nerve pallor. Obligate female carriers were clinically unaffected. Preliminary linkage analysis (lod score = 1.8) revealed that the disease gene localized to the OPA2 locus on Xp11.4-Xp11.2. Four forms of inherited optic neuropathy, ADOA, autosomal recessive optic atrophy (Costeff syndrome), Leber hereditary optic neuropathy, and charcot-marie-tooth disease with optic atrophy, are associated with mitochondrial dysfunction. Future identification of the XLOA gene will reveal whether this form of optic atrophy is also associated with a mitochondrial defect. Identification of the XLOA gene will advance our understanding of the inherited optic neuropathies and perhaps suggest treatments for these diseases. An improved understanding of inherited optic neuropathies may in turn advance our understanding of acquired optic nerve diseases, such as glaucoma and ischemic optic neuropathy.
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ranking = 2.6344907147214E-5
keywords = dominant
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20/20. Mutations of the mitochondrial holocytochrome c-type synthase in X-linked dominant microphthalmia with linear skin defects syndrome.

    The microphthalmia with linear skin defects syndrome (MLS, or MIDAS) is an X-linked dominant male-lethal disorder almost invariably associated with segmental monosomy of the Xp22 region. In two female patients, from two families, with MLS and a normal karyotype, we identified heterozygous de novo point mutations--a missense mutation (p.R217C) and a nonsense mutation (p.R197X)--in the HCCS gene. HCCS encodes the mitochondrial holocytochrome c-type synthase that functions as heme lyase by covalently adding the prosthetic heme group to both apocytochrome c and c(1). We investigated a third family, displaying phenotypic variability, in which the mother and two of her daughters carry an 8.6-kb submicroscopic deletion encompassing part of the HCCS gene. Functional analysis demonstrates that both mutant proteins (R217C and Delta 197-268) were unable to complement a saccharomyces cerevisiae mutant deficient for the HCCS orthologue Cyc3p, in contrast to wild-type HCCS. Moreover, ectopically expressed HCCS wild-type and the R217C mutant protein are targeted to mitochondria in CHO-K1 cells, whereas the C-terminal-truncated Delta 197-268 mutant failed to be sorted to mitochondria. Cytochrome c, the final product of holocytochrome c-type synthase activity, is implicated in both oxidative phosphorylation (OXPHOS) and apoptosis. We hypothesize that the inability of HCCS-deficient cells to undergo cytochrome c-mediated apoptosis may push cell death toward necrosis that gives rise to severe deterioration of the affected tissues. In summary, we suggest that disturbance of both OXPHOS and the balance between apoptosis and necrosis, as well as the X-inactivation pattern, may contribute to the variable phenotype observed in patients with MLS.
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ranking = 0.00013172453573607
keywords = dominant
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