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Biomedical subjects

N Abbadi

Publications and source records attributed to N Abbadi.

10 recordsLinked to original sources
PubMed1997

Disorganization in mice and humans and its relation to sporadic birth defects.

Disorganization (Ds) is a mouse mutant best known for producing an exceptional variety of unusual developmental anomalies, such as mirror-limb duplications and hamartomatous skin papillae. So great is the range of malformations that no two affected mice are identical. Several patients with a similar variety of exceptional anomalies have been reported, raising the possibility of the existence of a human homologue of Ds. However, although these human cases represent the most striking findings seen in Ds mice, they do not represent the full range of defects. Most affected mice have only a single malformation, and most of these malformations are similar to both common (neural tube defects, orofacial clefting, gastroschisis, limb reductions) and rare (anophthalmia, duplicated rectum) human birth defects. It is therefore possible that the full spectrum of the human homologue of Ds includes not only patients with the unusual combination of anomalies but also common sporadic birth defects. We suggest that the low penetrance (approximately 0-30%) and highly variable expression of Ds make it a paradigm for understanding the genetic basis for many seemingly sporadic birth defects.

Abnormalities, Multiple↗
PubMed1996

X chromosome inactivation in 30 girls with Rett syndrome: analysis using the probe.

Rett syndrome (RS) is a neurologic disorder with an exclusive incidence in females. A nonrandom X-inactivation could provide insight into the understanding of this disease. We performed molecular analysis based on the differential methylation of the active and inactive X with probe M27 beta, taking into account the parental origin of the two Xs, in 30 control girls, 8 sisters, and 30 RS girls. In 27 control an 31 RS mothers, the inactivation status of the X transmitted to their daughters was also analyzed. The results showed a significantly increased frequency of partial paternal X inactivation (> 65%) in lymphocytes from 16/30 RS compared with 4/30 controls (P = 0.001). These results do not support the hypothesis of a monogenic X-linked mutation but should be taken into account when researching the etiology of this disease.

DNA↗
PubMed1994

Additional case of female monozygotic twins discordant for the clinical manifestations of Duchenne muscular dystrophy due to opposite X-chromosome inactivation.

A pair of female monozygotic (MZ) twins, heterozygous carriers for a deletion in the DMD gene and discordant for the clinical manifestations of Duchenne muscular dystrophy, were analyzed by molecular studies, in situ hybridization, and methylation pattern of X chromosomes to search for opposite X inactivation as an explanation of their clinical discordance. Results in lymphocytes and skin fibroblast cell lines suggest a partial mirror inactivation with the normal X chromosome preferentially active in the unaffected twin, and the maternal deleted X chromosome preferentially active in the affected twin. A review shows that MZ female twins discordant for X-linked diseases are not uncommon. Twinning and X inactivation may be interrelated and could explain the female twins discordant for X-linked traits.

Base Sequence↗
PubMed1993

Physical mapping of DNA markers in the q13-q22 region of the human X chromosome.

DNA probe screening of somatic cell hybrids derived from females with X;autosome translocations has enabled us to define eight new breakpoints within the Xq13-q22 region. Together with other X-chromosome rearrangements that have been described earlier, these breakpoints subdivide the Xq21-q22 region into 20 intervals. Our panel refines the physical assignment of 40 probes in the Xq21-q22 segment. Thus, these X-chromosome rearrangements are useful tools for ordering X-linked markers and genes on the proximal long arm of the human X chromosome.

Amenorrhea↗
PubMedDate not supplied

New polymorphism and a new chromosome breakpoint establish the physical and genetic mapping of DXS369 in the DXS98-FRAXA interval.

Recently some of us cloned a new probe RN1 (DXS369), which appears a close marker for the fragile X locus (FRAXA) [Oostra et al.: Genomics 1990]. We present here new evidence for its physical and genetic mapping in the DXS98--FRAXA interval. We used 2 different somatic cell hybrid lines with breakpoints in the Xq27-q28 region: L10B Rea and PeCHN, and we established the order: (DXS105, DXS98)-L10B Rea-DXS369-PeCHN- (DXS304, DXS52). We detected an additional TaqI RFLP at the DXS369 locus which increases its informativeness up to 57%. Two point linkage analysis in a large set of families gave high lod scores for the FRAXA-DXS369 linkage (z(theta) = 10.1 at theta = 0.044) and for DXS369-DXS304, a marker distal to FRAXA (z = 19.2 at theta = 0.070). By multipoint analyses we established the localization of DXS369 in the DXS98-FRAXA interval. DXS369 is a much closer proximal marker for FRAXA than DXS105 or DXS98 and any new probe mapping between the breakpoints in L10B Rea and PeCHN will be of potential interest as a marker for FRAXA.

Adult↗
PubMedDate not supplied

Myoblast transplantation between monozygotic twin girl carriers of Duchenne muscular dystrophy.

Monozygotic twin girls, both carriers of Duchenne muscular dystrophy, only one a severe symptomatic carrier and the other asymptomatic due to opposite lyonization, were studied. Myoblast clones were obtained from a muscle biopsy of the asymptomatic carrier. PCR amplification showed that most (94%) of these clones produced normal dystrophin mRNA. Roughly 704 million myoblasts were produced from 119 clones. These myoblasts were transplanted into the extensor carpi radialis (ECR) and in the biceps of one arm of the manifesting carrier while the other arm acted as the control. The strength of the patient was evaluated in a series of pre- and post-tests and a biopsy was obtained about 1 yr after the transplantation. The myoblast injections produced a significant force gain (12%-31%) in wrist extension but no force gain for elbow flexion. Muscle biopsies on the injected and control muscles obtained 1 yr after the injections showed only a small increase in the number of dystrophin positive fibers and the presence of numerous small type II fibers. The small beneficial effect of this transplantation cannot be attributed to immune problems, the donor and the recipient being identical twins, but may be due to a low level of spontaneous muscle regeneration.

Adolescent↗