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T Vulliamy

Publications and source records attributed to T Vulliamy.

At least 19 recordsLinked to original sources
PubMed2005

New haplotype for the Glu104Asp mutation in triose-phosphate isomerase deficiency and prenatal diagnosis in a Spanish family.

First-trimester prenatal diagnosis was undertaken by chorionic villus DNA analysis in a Spanish family with the inherited Glu104Asp triose-phosphate isomerase deficiency. The fetus was heterozygous for the mutation and therefore predicted to be clinically unaffected. To investigate the evolutionary origin of this mutation, studies were conducted on the intragenic 2262A/G polymorphism and the CD4 pentameric tandem repeat marker. A different haplotype was found to the one previously described, suggesting a different origin of the Spanish mutation.

Aspartic Acid↗
PubMed2005

An Ashkenazi Jewish woman presenting with favism.

The case of a 44 year old Ashkenazi Jewish woman of Russian origin who presented with a typical clinical and haematological picture of favism is reported. There was initial difficulty in confirming glucose-6-phosphate dehydrogenase (G6PD) deficiency because the enzyme concentrations were normal at presentation, but later fell to a concentration compatible with heterozygosity for the Mediterranean type of G6PD deficiency. The diagnosis was also later confirmed by gene analysis. The reasons for the difficulties in the initial confirmation of the diagnosis and the normal G6PD enzyme activity at presentation are discussed.

Adult↗
PubMed2004

Lymphoid transformation in a CML patient in complete cytogenetic remission following treatment with imatinib.

We describe here a patient with Philadelphia (Ph) chromosome-positive chronic myeloid leukemia who achieved a complete cytogenetic response following treatment with imatinib and then progressed abruptly to lymphoid blastic transformation. The sequence of events suggests that at least in some cases patients who respond well to imatinib may still harbor residual leukemia progenitor or 'stem' cells that are susceptible to acquisition of molecular events that underlie progression to advanced phase disease. The case highlights the need for molecular monitoring of responders and the need to develop strategies for reducing to a minimum or totally eradicating leukemia cells.

Aged↗
PubMed2003

Non-TBI stem cell transplantation protocol for Fanconi anaemia using HLA-compatible sibling and unrelated donors.

Allogeneic haemopoietic stem cell transplantation (SCT) is the only curative option for severe bone marrow (BM) failure in patients with Fanconi anaemia (FA). We have developed a non total body irradiation (TBI) conditioning protocol consisting of fludarabine (120-150 mg/m(2)), low dose of cyclophosphamide (40 mg/kg) and antilymphocyte globulin (45 mg/kg). Graft-versus-host disease (GVHD) prophylaxis was with cyclosporin alone for sibling allografts but also included Campath-1 H (days 1-5 post SCT) for the unrelated allografts. We have performed two sibling and two unrelated BM transplants with a follow-up of 11-51 months. All patients experienced minimal toxicity and were discharged from hospital 28-32 days post SCT. Neutrophil and platelet engraftment occurred from days 11 to 19 and 15 to 34, respectively. All patients achieved stable full donor haemopoiesis with normalisation of the peripheral blood count despite one of them having myelodysplasia (MDS) with 8% blasts prior to the SCT. The only site of acute GVHD was in the skin (grade I-II) and only one patient progressed to limited chronic GVHD. This protocol is associated with reduced toxicity and prompt engraftment in FA patients with AA and/or MDS undergoing SCT using sibling or unrelated donors.

Adolescent↗
PubMed2001

The RNA component of telomerase is mutated in autosomal dominant dyskeratosis congenita.

Dyskeratosis congenita is a progressive bone-marrow failure syndrome that is characterized by abnormal skin pigmentation, leukoplakia and nail dystrophy. X-linked, autosomal recessive and autosomal dominant inheritance have been found in different pedigrees. The X-linked form of the disease is due to mutations in the gene DKC1 in band 2, sub-band 8 of the long arm of the X chromosome (ref. 3). The affected protein, dyskerin, is a nucleolar protein that is found associated with the H/ACA class of small nucleolar RNAs and is involved in pseudo-uridylation of specific residues of ribosomal RNA. Dyskerin is also associated with telomerase RNA (hTR), which contains a H/ACA consensus sequence. Here we map the gene responsible for dyskeratosis congenita in a large pedigree with autosomal dominant inheritance. Affected members of this family have an 821-base-pair deletion on chromosome 3q that removes the 3' 74 bases of hTR. Mutations in hTR were found in two other families with autosomal dominant dyskeratosis congenita.

Cell Line↗
PubMed2001

Fludarabine-based stem cell transplantation protocol for Fanconi's anaemia in myelodysplastic transformation.

Allogeneic stem cell transplantation (SCT) represents the treatment of choice for severe bone marrow (BM) failure in patients with Fanconi's anaemia (FA). However, for FA patients developing leukaemic or myelodysplastic transformation, the results of SCT are much less encouraging. We present a 17-year-old girl with myelodysplastic transformation of FA (refractory anaemia with excess blasts) and oculocutaneous albinism, who was treated by sibling SCT using conditioning with fludarabine, cyclophosphamide (CY) and anti-lymphocyte globulin (ALG). She had rapid engraftment with no toxicity and no graft-versus-host disease (GVHD). Twenty-two months after SCT, she had 100% donor chimaerism on Southern blot analysis.

Adolescent↗
PubMed2001

Analysis of chimaerism in thalassaemic children undergoing stem cell transplantation.

We have prospectively assessed the relative contribution of host and donor to haemopoiesis following stem cell transplantation (SCT) in children with beta-thalassaemia major (n = 35), using karyotype analysis or Southern blot/polymerase chain reaction analysis of variable number tandem repeats on genomic DNA from peripheral blood. Early haemopoiesis was fully donor in origin in 24 out of 35 cases and remained so throughout the post-transplant course in all but one patient, who evolved to stable mixed chimaerism. The remaining 11 cases (31%) initially showed mixed chimaerism: four of these rejected, one eventually eradicated host haemopoiesis to become fully donor haemopoietic, and the remaining six had persistent mixed chimaerism, with 5--38% host haemopoiesis. The risk of graft rejection was high when > 15% host haemopoiesis was present at 3 months post transplant: four out of six such patients rejected their grafts; conversely, zero out of 29 patients with < 15% host haemopoiesis at 3 months rejected (P < 0.0001). There was a higher incidence of significant acute and chronic graft-versus-host disease in patients with full donor chimaerism. These studies confirm that the mixed chimaeric state is common following SCT for thalassaemia, often persists (with up to 4 years follow-up) and is compatible with long-term cure. Analysis of chimaerism in patients undergoing SCT for beta-thalassaemia enables monitoring of engraftment in the early post-transplant period, provides insight into the biology of engraftment and may be useful in identifying patients at high risk of rejection.

ABO Blood-Group System↗
PubMed1999

Three major G6PD-deficient polymorphic variants identified among the Mauritian population.

We report the results of the first epidemiological study investigating glucose 6-phosphate dehydrogenase (G6PD) deficiency among the heterogenous Mauritian population. Mauritius has a population of approximately 1 million, and of these 66.8% are Indo-Mauritian (of Indian origin), 27.9% are Creoles (of African ancestry) and 2.1% are Sino-Mauritian, predominantly of Chinese origin. Of the 1435 Mauritian males tested, 73 (5.1%) were G6PD deficient. However, the prevalence varied considerably between the two major ethnic groups: 35/1157 (3.0%) for Indo-Mauritians and 37/267 (13.9%) for Creoles. Molecular analysis revealed three major deficient polymorphic variants; G6PD Orissa, G6PD Mediterranean and G6PD A-. G6PD Orissa (nt 131 G-->C; residue 44 Ala-->Gly) was found to be the most common variant among Indo-Mauritians: this deficient variant was recently identified to be highly characteristic of the tribal groups in central India. In Creoles the most common deficient variant was G6PD A- (27/37). These data are consistent with the different ancestral contributions to the present gene pool of the Mauritian population. This study has provided further information as to the precise nature of G6PD deficiency at the molecular level among Indians, about whom previously there was scant information. The data presented suggest that G6PD Orissa is widespread in central and southern states of India. Additionally, the identification and frequency of G6PD-deficient alleles in Mauritius is of public-health importance.

Electrophoresis↗
PubMed1998

Dyskeratosis Congenita (DC) Registry: identification of new features of DC.

Dyskeratosis congenita (DC) is an inherited disorder characterized by skin pigmentation, nail dystrophy and mucosal leucoplakia. In 1995 a Dyskeratosis Congenita Registry was established at the Hammersmith Hospital. In the 46 families recruited, 76/83 patients were male, suggesting that the major form of DC is X-linked. As well as a variety of noncutaneous abnormalities, the majority (93%) of patients had bone marrow (BM) failure and this was the principal cause (71%) of early mortality. In addition to BM hypoplasia, some patients also developed myelodysplasia and acute myelod leukaemia. Pulmonary abnormalities were present in 19% of patients. In affected females the phenotype was less severe. Some female carriers of X-linked DC had clinical features. Carriers of X-linked DC showed skewed X-chromosome inactivation patterns (XCIPs), suggesting that cells expressing the normal DC allele have a growth/survival advantage over cells that express the mutant allele. Linkage analysis in multiplex families confirmed that the DKC1 gene, responsible for the X-linked form of DC, is located within Xq28 and facilitated its positional cloning. The high incidence of BM failure in association with a wide range of somatic abnormalities together with the ubiquitous expression of DKC1 suggest that, as well as having a critical role in normal haemopoiesis, this gene has a key role in normal cell biology.

Adolescent↗
PubMed1997

Clonal instability preceding lymphoid blastic transformation of chronic myeloid leukemia.

We have sought the presence of rearrangements of the immunoglobulin heavy chain gene locus in 13 patients with chronic myeloid leukemia (CML) in lymphoid blastic transformation (L-BT) using the polymerase chain reaction (PCR). The lymphoid nature of the transformation was confirmed by immunophenotyping and/or Southern blot hybridization with a J(H) probe. Clonal rearrangements were detected in 85% of cases and two or more rearrangements were visible in 64% of informative cases. The pattern of V(H) gene family utilization revealed an apparent reduction in V(H)4 family gene usage but otherwise reflected the known proportion of each gene family in the germline repertoire. In six cases the third complementary determining regions (CDR3) of the predominant blast crisis clone/s were sequenced revealing minimal evidence of somatic mutation. No clonal changes were detected in the chronic phase leukemia cells collected more than 6 months before the onset of L-BT in three of these patients. Of the other three patients studied in chronic phase from 1 to 6 months before L-BT, two showed clonal rearrangements which differed in size from those present at L-BT. In one patient a V(H)3 to V(H)5-D(H)-J(H) substitution had occurred at least 3 months prior to L-BT. In the other patient, however, the sequence of the rearrangement present 5 months prior to L-BT was unrelated to the rearrangements at the time of L-BT indicating a pattern of clonal succession. We conclude that: (1) IgH gene rearrangements are detectable in the majority of patients with L-BT using PCR and the lymphoid lineage of blastic CML is most readily confirmed using consensus primers to the framework 3 region; (2) somatic mutation is uncommon; and (3) B lymphoid clones distinct from those identified later may be detected before overt lymphoid BT. The identification of such 'abortive' clones is evidence for clonal instability before the onset of transformation and might have prognostic value.

Adolescent↗
PubMed1996

Independent origin of single and double mutations in the human glucose 6-phosphate dehydrogenase gene.

The vast majority of both polymorphic and sporadic G6PD variants are due to single missense mutations. In the four polymorphic variants that have two point mutations, one of the mutations is always 376 A-->G (126 Asn-->Asp), which on its own gives rise to the nondeficient polymorphic variant, G6PD A. In a study of G6PD deficient patients who presented with clinical favism in Spain, we have found a new polymorphic variant that we have called G6PD Malaga, whose only abnormality is a 542 A-->T (181 Asp-->Val) mutation. This is the same mutation as previously found in association with the mutation of G6PD A in the double mutant, G6PD Santamaria. G6PD Malaga is associated with enzyme deficiency (class III), and the enzymic properties of G6PD Malaga and G6PD Santamaria are quite similar, indicating that in this case the effects of the two mutations are additive rather than synergistic. G6PD Santamaria might have been produced by recombination between G6PD A and G6PD Malaga; however haplotype analysis, including the use of a new silent polymorphism, suggests that the same 542 A-->T mutation has taken place independently in a G6PD B gene to give G6PD Malaga and in a G6PD A gene to give G6PD Santamaria. These findings help to outline the relationship and evolution of mutations in the human G6PD locus.

Amino Acid Sequence↗
PubMed1996

Fine mapping of the dyskeratosis congenita locus in Xq28.

Dyskeratosis congenita (DC) is characterised by reticulate skin pigmentation, mucosal leucoplakia, and nail dystrophy. Bone marrow failure occurs in 50% of patients and is the principal cause of early mortality. In the majority of families the pattern of inheritance of DC is compatible with an X linked recessive trait. The locus for the X linked recessive form of DC has been linked to Xq28. We have now extended our earlier studies by investigating five families with additional Xq28 polymorphic markers; analysis of recombination events in these families has located the DC1 locus between GABRA3 and DXS1108, an interval of approximately 4 Mb.

Abnormalities, Multiple↗
PubMed1996

DNA haplotypes in Africans and West Indians with sickle cell anaemia or SC disease.

Considering that genetic variation linked to the beta S mutation may influence the clinical manifestations of sickle cell disease, we have analyzed the beta globin cluster haplotypes in 47 patients with this condition (33 SS homozygotes, one S/beta thal (0), and 13 SC) living in London (30 West Indian, 17 West African). Of the 80 chromosomes tested, 82.5% had the Benin haplotype and of the 13 C chromosomes tested, 85% had the Bantu-A4 haplotype. A minority of patients had Bantu or Senegal haplotypes, and in 5 patients we found new haplotypes called E, H and O which may have arisen through mutation or recombination. Because of the predominance of a single haplotype (Benin) nearly all our homozygous S patients were either homozygous or heterozygous for this haplotype. We concluded that the beta globin haplotype is unlikely to be an important determinant of the clinical severity in this patient population.

Africa, Western↗