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Biomedical subjects

M Baiget

Publications and source records attributed to M Baiget.

At least 127 records · Page 7Linked to original sources
PubMed1995

Influence of the sex of the transmitting grandparent in congenital myotonic dystrophy.

To analyse the influence of the sex of the transmitting grandparents on the occurrence of the congenital form of myotonic dystrophy (CDM), we have studied complete three generation pedigrees of 49 CDM cases, analysing: (1) the sex distribution in the grandparents' generation, and (2) the intergenerational amplification of the CTG repeat, measured in its absolute and relative values, between grandparents and the mothers of CDM patients and between the latter and their CDM children. The mean relative intergenerational increase in the 32 grandparent-mother pairs was significantly greater than in the 56 mother-CDM pairs (Mann-Whitney U test, p < 0.001). The mean expansion of the grandfathers (103 CTG repeats) was also significantly different from that seen in the grandmothers' group (154 CTG repeats) (Mann-Whitney U test, p < 0.01). This excess of non-manifesting males between the CDM grandparents' generation with a smaller CTG length than the grandmothers could suggest that the premutation has to be transmitted by a male to reach the degree of instability responsible for subsequent intergenerational CTG expansions without size constraints characteristic of the CDM range.

Base Sequence↗
PubMed1995

Inversion of intron 22 in isolated cases of severe hemophilia A.

Inversion involving intron 22 is the commonest type of mutation causing severe hemophilia A (HA). We investigated 15 families with isolated cases and 5 families with two or three brothers as the only affected members with hemophilia A, in order to determine the carrier status of the mothers, the origin of the mutation and the presence of germinal mosaicism. Our results show that all mothers tested were carriers of the inversion. In addition, three families whose unique hemophilic member was not available for analysis, were screened for the inversion. In one of these last families, the mother was diagnosed as a carrier and her sister and her niece as non-carriers. DNA haplotype analysis in 8 families with grandparents available for study demonstrated that the inversion originated almost exclusively in male germ cells. These findings have important relevance for genetic counselling in families with an isolated case or to exclude germinal mosaicism. Inversion analysis should constitute the first step in molecular diagnosis of severe hemophilia A.

Chromosome Inversion↗
PubMed1995

Various patterns of chimerism after allogeneic bone marrow transplantation for advanced chronic lymphocytic leukemia.

Chimerism studies after allogeneic BMT are performed to determine the donor and/or recipient origin of peripheral blood and marrow lymphoid and hematopoietic cells. These studies have been performed mostly in leukemias and aplastic anemia. We report DNA-based chimerism studies in three patients transplanted for advanced CLL from a histocompatible sibling. Following conditioning with chlorambucil, cyclophosphamide and TBI all three successfully engrafted. One has remained in continuous complete remission (CR) with a complete donor chimerism (CDC) for 110 months post-BMT. Another was in mixed chimerism (MC) with minimal residual disease (MRD) at 3 months post-BMT but was in CR and in CDC at 6 months, suggesting that the persistent CLL cells has disappeared between these two studies. The third patient has been in persistent MC since BMT (24 months follow-up), although he is in CR with no evidence of persistent CLL. We postulate that this patient's MC status is due to normal residual recipient lymphohematopoietic cells that survived the conditioning regimen. In conclusion, various patterns of chimerism can be observed in CLL patients after BMT while remaining in CR and with no evidence of residual CLL.

Adult↗
PubMed1995

[Basic concepts in molecular genetics].

Recombinant DNA technology has made great strides in recent years, enabling researchers to manipulate genetic material for the study of fundamental phenomena in biology and pathological processes that are well defined in clinical practice. Advances have been made toward defining some of these diseases in molecular biological terms with a diagnostic precision that was unimaginable only a few years ago. From a theoretical standpoint, the technical possibilities for studying the genome are unlimited, obliging the medical profession to focus on the molecular level, not only to further understanding of the pathophysiological processes that underpin disease but also to consider their diagnostic and therapeutic implications.

Blotting, Southern↗
PubMed1995

[Dystrophinopathies].

In 1987 a new concept in the X-linked muscular dystrophies was born with the identification of dystrophin, a cytoskeletal protein responsible for several muscular diseases previously grouped as Duchenne's or Becker's muscular dystrophies (DMD and BMD, respectively). Under the new concept these entities are referred to as dystrophinopathies. The discovery of dystrophin was made possible when polymerase chain reaction and reverse genetics opened the door to DNA examination. The DMD/BMD gene was located and sequenced and the protein product, dystrophin, was fully identified. The genetic study of dystrophinopathies was extended in the 1990's to include DNA analysis aimed at 1) discovering points of deletion or mutation that give rise to Xp21 myopathies, as dystrophinopathies are also known; 2) identifying the rules of protein translation (interruption or reading "signals" of the protein's genetic code), and 3) identifying atypical clinical phenotypes that can be diagnosed on a molecular level using anti-dystrophin antibodies or DNA probes.

Chromosome Aberrations↗
PubMed1994

Genetic fine localization of the arrestin (S-antigen) gene 4 cM distal from D2S172.

Arrestin is a component of the light transduction cascade that takes place in the outer segment of retinal rods. In situ hybridization and linkage analysis have localized the arrestin gene to a region of 50 cM between CRYG alpha and D2S23/D2S55 on chromosome 2q24-37. We have performed pairwise and multipoint linkage analysis between arrestin and four highly polymorphic markers from this region. The results indicate tight linkage between the gene and the microsatellite D2S172 (Zmax = 9.25 at theta = 0.038). This fine localization of the gene should provide a useful tool for cosegregation analyses involving the arrestin gene.

Antigens↗
PubMed1994

Hemophilia A or von Willebrand disease?

Seven members of the same family were studied on several occasions due to a history of hemorrhages. The propositus, a 12-year-old boy, his sister, one brother, and their father all had a low plasma factor VIII (FVIII) level. Von Willebrand factor (vWF) activity, vWF multimeric analysis, and vWF factor domain for binding to FVIII were normal in all seven subjects. The sister had a normal 46XX karyotype. The study of two intragenic restriction fragment length polymorphisms (RFLPs) and two closely linked, highly polymorphic extragenic markers showed a phenotypic expression of mild hemophilia A, which suggests that the sister of the propositus is homozygous or compound heterozygous at the hemophilia A locus. She would have inherited two hemophilic genes: one from her carrier mother and the other from her father, a mild hemophiliac.

Binding Sites↗
PubMed1994

Severe mental retardation in a young boy with an in-frame deletion in the dystrophin gene.

We report here a mentally retarded 32-month-old boy whose initial diagnosis was Angelman syndrome based on his clinical features. Cytogenetic studies showed a normal karyotype. Due to an elevated level of serum creatine kinase activity, we performed analyses to rule out a myopathic process. Although the electromyogram was normal, a few scattered necrotic fibres were seen in the muscle biopsy. DNA and dystrophin studies revealed an in-frame deletion in the 5' region of the dystrophin gene and an abnormal form of the protein product, consistent with a diagnosis of dystrophinopathy. We cannot totally rule out the possibility that this boy has the two separate conditions.

Child, Preschool↗
PubMed1994

Identification by molecular diagnosis of mosaic Turner's syndrome in an obligate carrier female for fragile X syndrome.

A case of mosaic Turner's syndrome with a 45,X/46,XX/47,XXX karyotype, who was also a fragile X obligate carrier as the mother of an affected boy, was identified by molecular diagnosis. Complete haplotyping and direct DNA analysis showed that the X chromosome in all metaphases was the normal X. At the age of 57, she is mentally normal. Her external appearance was typical of Turner's syndrome. This report shows that molecular studies in conjunction with cytogenetic analysis can help in the clinical diagnosis of a rare case and can show the uniqueness of a case such as the one here described.

Female↗
PubMed1994

Anticipation in myotonic dystrophy: a parental-sex-related phenomenon.

We report anticipation in an extensive sample of myotonic dystrophy (MyD) kindreds taken from an epidemiological survey recently conducted in Guipúzcoa, Spain. Analysis of the parent-child pairs ascertained showed a mean anticipation of 2.86 decades (range 0-6). Greater anticipation occurred when the transmissor parent was the mother. These results suggest a possible sex-related effect in the transmission of the MyD gene, and are in agreement with recent discoveries at the molecular level.

Adolescent↗
PubMed1994

Second bone marrow transplantation for leukemia in untreated relapse.

Seven patients with relapsed acute leukemia (4 ANLL, 3 ALL) and one with juvenile chronic myelomonocytic leukemia (JCMML) received a second BMT (BMT2). Patients were conditioned with CY/TBI (n = 7) or BU/CY (n = 1) for the first BMT (BMT1), with adequate recovery in all and without the appearance of acute GVHD (n = 3) or with mild forms (grade I, n = 2; grade II, n = 3). Relapse after BMT1 occurred in < 6 months (n = 2), between 6 and 12 months (n = 5) and > 12 months (n = 1), and the interval from BMT1 to BMT2 was < 6 months (n = 1), from 6 to 12 months (n = 5) or > 12 months (n = 2). Conditioning for BMT2 was done in untreated relapse and included combinations of BU/CY (n = 2), CY/TBI (n = 1) or BU 1 mg/kg at intervals of 6 h by mouth on days -7 to -4 and melphalan 180 mg/m2 i.v. on day -2, with the addition of VP-16 in the patient with JCMML. Two patients died on day +11 with no evidence of residual leukemia at autopsy. Six patients engrafted, one of whom had an uneventful BMT2, but he relapsed 6 months later. The other five developed severe acute GVHD (grades III-IV), with a fatal outcome in three cases, while two responded to treatment and are currently alive in continuous CR at 12 and 36 months. All patients had received conventional prophylaxis against acute GVHD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗