1/4. Submicroscopic Xpter deletion in a boy with growth and mental retardation caused by a familial t(X;14).In a 3-year-old boy with short stature, developmental delay, and dry skin, steroid sulphatase deficiency and a submicroscopic terminal deletion of Xp were found. Except for the short stature, no major clinical signs of X-linked recessive chondrodysplasia punctata could be observed. His mother had lowered steroid sulphatase activity compatible with carriership for X-linked ichthyosis and a submicroscopic translocation (X;14)(p22.31;p11.1). This finding combined with a normal amplification of exons 1, 5, and 10 of the STS gene from propositus' dna suggested a breakpoint upstream of the STS gene. The submicroscopic maternal translocation had important implications for genetic counseling. This case report illustrates that contiguous gene syndrome related to the Xpter region may have an atypical clinical presentation and the usefulness of combined clinical, biochemical, molecular, and fluorescence in situ hybridization analysis.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/4. An Xp; Yq translocation causing a novel contiguous gene syndrome in brothers with generalized epilepsy, ichthyosis, and attention deficits.PURPOSE: We describe two brothers with generalized epilepsy, attention deficits, congenital ichthyosis, and Leri-Weill dyschondrosteosis who harbor an unusual Xp; Yq translocation chromosome, resulting in a novel contiguous gene syndrome because of deletion of genes from the distal short arm of the x chromosome. methods: physical examination, neuropsychologic testing, EEG, and neuroimaging studies were performed. Because of their unusual phenotype, karyotyping, fluorescence in situ hybridization, and further molecular analyses were carried out to refine the break points of the underlying unbalanced sex chromosome rearrangement. RESULTS: The subjects had generalized epilepsy, X-linked ichthyosis, Madelung deformities, mesomelia, normal intelligence, and attention deficits. The brothers' karyotype was unbalanced; they inherited a maternal derivative x chromosome. Deleted distal Xp genes included short-stature homeobox on the x chromosome (SHOX), aryl sulfatase E (ARSE), variably charged X-chromosome mRNA gene A (VCX-A), and steroid sulfatase (STS). The final karyotype was 46,Y,der(X)t(X; Y)(p22.3; q11.2).ish der(X) (DXZ1 , KAL , STS-, SHOX-) mat. CONCLUSIONS: Loss of distal contiguous Xp genes resulted in a syndrome comprising bony deformities, ichthyosis, attention problems, and generalized epilepsy. Candidate epilepsy genes within the deleted segment, such as ASMT, a gene involved in the final synthesis of melatonin, are discussed. Cytogenetic analyses should be included in the clinical evaluation of patients with generalized epilepsy and complex phenotypes.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/4. prenatal diagnosis for placental steroid salfatase deficiency with fluorescence in situ hybridization: a case of X-linked ichthyosis.X-linked ichthyosis (XLI) is a relatively common genetic disorder that occurs in about one in every 2000-6000 male births. Clinically, XLI is characterized by a generalized scaling of the skin, with large, polygonal, dark brown scale, and more prominent on the extensor aspects of the limbs. It is known that an undetectable maternal serum, unconjugated estriol, associated with placental steroid sulfatase (STS) deficiency, may be the cause of cause of XLI. In most case, STS deficiency is caused by a complete or partial deletion of the STS gene mapped on chromosome Xp22.3. We describe here the prenatal detection of a male fetus affected with STS deficiency as a result of an undetectable unconjugated estriol in the second-trimester maternal serum screening. Microdeletion of the STS gene was confirmed by fluorescence in situ hybridization analysis of cultured amniotic fluid.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
4/4. prenatal diagnosis of X-linked ichthyosis using molecular cytogenetics.A case is presented in which X-linked ichthyosis was diagnosed prenatally using fluorescence in situ hybridization. Fetal sex was known by second trimester ultrasound in a woman with very low second trimester MSUE3. All of the 15 maternal peripheral blood metaphase spreads examined displayed two hybridization signals on one x chromosome (one in the steroid sulfatase region (Xp22.3) and one in the centromeric region), but only one hybridization signal (in the X centromeric region) on the other x chromosome. Thus, one of the x chromosome had a deletion in the Xp22.3 region, a result which was consistent with carrier status for steroid sulfatase deficiency and X-linked ichthyosis. In the 15 metaphase spreads that were examined from the amniotic fluid sample, the x chromosome displayed one hybridization signal in the control region, but no hybridization signal in the steroid sulfatase region. Thus, the x chromosome of this male fetus had a deletion in the steroid sulfatase region, a result that was consistent and demonstrated postpartum X-linked ichthyosis.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |