✦ LIBER ✦

Mosaicism for a full mutation and a normal size allele in two fragile X males

✍ Scribed by Schmucker, Beatrice; Seidel, J�rg

Publisher: John Wiley and Sons
Year: 1999
Tongue: English
Weight: 20 KB
Volume: 84
Category: Article
ISSN: 0148-7299
DOI: 10.1002/(sici)1096-8628(19990528)84:3<221::aid-ajmg11>3.0.co;2-m

No coin nor oath required. For personal study only.

✦ Synopsis

Confirmation of the clinical diagnosis of fragile X syndrome by molecular tests is based on both the presence of a full mutation and methylation of the promotor region of the FMR1 gene. The mechanism leading to mosaic alleles of repeat number and the role of methylation in this process is still under discussion. We report two cases of males who show mosaic patterns for both number of CGG repeats and methylation status. In the first patient, a mosaic pattern of a normal allele of 34+/-1 CGGs, a borderline premutation/full mutation, and a full mutation was observed. The mother exhibited alleles of 30+/-1 and approximately 100 CGGs. The second patient was mosaic for a normal allele of 47+/-1 CGGs and a full mutation. His mother carried alleles of 40+/-1 and approximately 100 CGGs. Chromosomal analysis in the patients showed normal male karyotypes with no evidence that they had inherited both maternal X chromosomes. Furthermore, haplotyping excluded disomy of the repeat flanking region in these patients. So far, it is not clear whether the normal alleles in the patients, leukocytes of 34 and 47 CGGs, respectively, may be caused by the contraction of the maternal premutations of 100 CGGs or be caused by the deletion from the full mutation alleles.

📜 SIMILAR VOLUMES

Mosaicism for full mutation and normal-s

Mosaicism for full mutation and normal-sized allele of the FMR1 gene: A new case

✍ Orrico, Alfredo; Galli, Lucia; Dotti, Maria Teresa; Plewnia, Katrin; Censini, St 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 15 KB 👁 1 views

The main mutation in fragile X patients is the expansion of the CGG repeat in the first exon of the FMR1 gene, associated with hypermethylation of the proximal CpG island. An increasing number of atypical cases have been reported showing the coexistence of full mutation and premutated or normalsized

Nonrandom X inactivation and selection o

Nonrandom X inactivation and selection of fragile X full mutation in fetal fibroblasts

✍ Sun, Y.J.; Baumer, A. 📂 Article 📅 1999 🏛 John Wiley and Sons 🌐 English ⚖ 11 KB

In the fragile X female carriers the degree of cognitive impairment appears to be correlated with activation status of the X chromosome bearing the expanded trinucleotide repeat in the promoter of the FMR1 gene. In this study we asked if the deviations from the primarily random pattern of X inactiva

Mosaicism for the full mutation and a mi

Mosaicism for the full mutation and a microdeletion involving the CGG repeat and flanking sequences in theFMR1 gene in eight fragile X patients

✍ Grasso, M.; Faravelli, F.; Nigro, C. Lo; Chiurazzi, P.; Sperandeo, M.P.; Argusti 📂 Article 📅 1999 🏛 John Wiley and Sons 🌐 English ⚖ 32 KB 👁 1 views

The molecular mechanism of the fragile X syndrome is based on the expansion of an unstable CGG repeat in the 5 untranslated region of the FMR1 gene in most patients. This expansion is associated with an abnormal DNA methylation leading to the absence of production of FMR1 protein (FMRP). Such expans

Somatic and germ line mosaicism and muta

Somatic and germ line mosaicism and mutation origin for a mutation in theL1 gene in a family with X-linked hydrocephalus

✍ Du, Jian-Sheng; Bason, Lynne; Woffendin, Hayley; Zackai, Elaine; Kenwrick, Susan 📂 Article 📅 1998 🏛 John Wiley and Sons 🌐 English ⚖ 11 KB 👁 2 views

X-linked hydrocephalus is caused by mutations in the gene for neural cell adhesion molecule L1 (L1CAM). In this report, we describe identification of a mutation in an isolated case of hydrocephalus with adducted thumbs. Tracing the origin of the mutation within the family showed a degree of somatic

Postmortem examination of two fragile X

Postmortem examination of two fragile X brothers with anFMR1 full mutation

✍ Reyniers, Edwin; Martin, Jean-Jacques; Cras, Patrick; Van Marck, Eric; Handig, I 📂 Article 📅 1999 🏛 John Wiley and Sons 🌐 English ⚖ 19 KB 👁 1 views

Large expansions of the CGG repeat in the 5' untranslated region of the FMR1 gene are found in patients with the fragile X syndrome. Amplified CGG repeats in FMR1 are unstable and show intergenerational increase from mother to offspring. The exact timing of repeat amplification, however, is unknown.

Tissue heterogeneity of theFMR1 mutation

Tissue heterogeneity of theFMR1 mutation in a high-functioning male with fragile X syndrome

✍ Taylor, Annette K.; Tassone, Flora; Dyer, Pamela N.; Hersch, Steven M.; Harris, 📂 Article 📅 1999 🏛 John Wiley and Sons 🌐 English ⚖ 33 KB 👁 1 views

Few studies have been conducted comparing the FMR1 mutation in multiple tissues of individuals affected with fragile X syndrome. We report a postmortem study of the FMR1 mutation in multiple tissues from a high-functioning male with fragile X syndrome. This man was not mentally retarded and had only