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Biomedical subjects

J S Waye

Publications and source records attributed to J S Waye.

At least 37 records · Page 2Linked to original sources

Late-onset metachromatic leukodystrophy clinically presenting as isolated peripheral neuropathy: compound heterozygosity for the IVS2+1G-->A mutation and a newly identified missense mutation (Thr408Ile) in a Spanish family.

We report the case of a 50-year-old woman and her 32-year-old daughter, both of whom are affected with adult-onset metachromatic leukodystrophy (MLD) clinically presenting as peripheral neuropathy. Arylsulfatase A (ARSA) activities were markedly reduced, and electrophysiology showed a severe demyelinating neuropathy with features of chronic acquired demyelinating polyneuropathy. Molecular genetic studies of the family revealed that the proband and her affected daughter are compound heterozygotes for the common IVS2+ 1G-->A mutation and a newly identified missense mutation, Thr408Ile. This case indicates that adult metachromatic leukodystrophy should be considered in adult patients with demyelinating peripheral neuropathy of unknown etiology.

Alleles↗

PCR-based diagnosis of the Filipino (--(FIL)) and Thai (--(THAI)) alpha-thalassemia-1 deletions.

In southeast Asia, the carrier frequency of two-gene alpha-thalassemia deletions is quite high, ranging from 4% to 14% depending on the population. The most common alpha-thalassemia-1 deletion is the so-called southeast Asian deletion (--(SEA)). In addition, a significant proportion of cases involve two other deletions, the Filipino (--(FIL)) and Thai (--(THAI)) deletions. In this report, we identify the deletion breakpoints for the (--(FIL)) and (--(THAI)) deletions, and describe PCR-based protocols for rapid and reliable DNA diagnosis of these deletions.

Asia, Southeastern↗

beta-thalassemia intermedia caused by compound heterozygosity for Hb Malay (beta codon 19 AAC-->AGC; asn-->Ser) and codons 41/42 (-CTTT) beta(0)-thalassemia mutation.

We report a case of beta-thalassemia intermedia caused by compound heterozygosity for hemoglobin (Hb) Malay and codon 41/42 (-CTTT) beta(0)-thalassemia mutation in a 38-year-old Chinese woman. This patient has long-standing anemia with a baseline Hb level of around 70 g/L. She worked as a full-time cashier and had not required regular blood transfusions. Nevertheless, she had splenomegaly necessitating splenectomy, cholelithiasis, and iron overload. This case illustrates the varied phenotypic expression associated with compound heterozygosity for Hb Malay and other beta-thalassemia mutations. Since Hb Malay migrates as Hb A on electrophoresis and chromatography, this variant Hb mutation ought to be included in the differential diagnosis for beta-thalassemia major or intermedia patients of Southeast Asian descent who are reported to have Hb A on the basis of Hb analysis. The possible presence of this mutation should also be considered in appropriate cases for genetic counseling in couples at risk of conceiving fetuses with beta-thalassemia major or intermedia.

Adult↗

A reliable screening test to identify adult carriers of the (--SEA) alpha zero-thalassemia deletion. Detection of embryonic zeta-globin chains by enzyme-linked immunosorbent assay.

Homozygous (--SEA) alpha zero-thalassemia deletion, the cause of up to 80% of fetal hydrops in Southeast Asia, is encountered in many other countries. Heterozygous carrier rates of the deletion in Southeast Asian populations range from 4% to 14%. The laboratory screening for adult carriers of (--SEA) and other alpha zero-thalassemia deletions currently rests primarily with microscopic detection of hemoglobin H inclusion bodies within erythrocytes (Hb H screen). This test is laborious and observer dependent and has poor sensitivity. We assessed a colorimetric enzyme-linked immunosorbent assay (ELISA) to detect embryonic zeta-globin chains in adult hemolysates as an alternative to detect (--SEA) alpha zero-thalassemia deletion carriers. Blood samples from 221 adults with a mean corpuscular volume less than 80 micron 3 (80 fL) were studied prospectively by currently accepted hemoglobin screening tests and ELISA. Suspected cases of alpha-thalassemia were confirmed by DNA-based diagnostics. ELISA was highly sensitive (1.0) and specific (0.94) for the detection of adult carriers of (--SEA) alpha zero-thalassemia deletion. The hemoglobin H screen had a sensitivity of 0.47 and specificity of 0.99. The zeta-globin ELISA proved simple to perform, rapid, and applicable to high volume or population-based screening programs.

Adult↗

A novel and de novo spontaneous point mutation (Glu271STOP) of the antithrombin gene results in a type I deficiency and thrombophilia.

We describe a novel, de novo point mutation in one antithrombin (AT) allele resulting in type I AT deficiency and thrombophilia. Low plasma AT activity as well as low plasma AT antigen were documented in the propositus, but not in the parents, or in a male sibling. AT gene analysis by sequencing polymerase chain reaction-amplified genomic DNA from exon 5 of the propositus revealed a novel point mutation, GAG-->TAG at codon 271, resulting in a stop codon (Glu271STOP). This mutation was not demonstrable in the other members of his immediate family. DNA marker polymorphism analysis indicated the expected parentage. Based on allele frequency data for Caucasians in the United States the cumulative paternity index, or CPI, for the propositus and his father is 219,077. This corresponds to a probability of paternity of 99.9995% based on a prior probability of 50%. Included in this analysis is a linkage analysis of a trinucleotide repeat in intron 5 of the AT gene of the various family members, which also confirmed maternity and paternity. These studies provide documentation of the first spontaneous mutation of an AT gene in a thrombophilic individual, resulting in a type I AT deficiency.

Adolescent↗

Parentage testing implications of male fertility after allogeneic bone marrow transplantation.

Fertility is expected to be reduced after the extensive chemotherapy and/or radiotherapy that is needed for conditioning prior to bone marrow transplantation. However, a male patient can be fertile, and in very rare situations such as reported here, this may confuse subsequent paternity testing. The patient, initially excluded as the biological father by red cell types but not by HLA, was subsequently included after the history of his previous marrow transplant was revealed, a review of the HLA results and further RFLP testing on buccal mucosal cells. This case points to the need for good history taking before performing paternity testing.

Adult↗

Elimination of transfusions through induction of fetal hemoglobin synthesis in Cooley's anemia.

Pharmacological stimulation of fetal hemoglobin production is of considerable interest as an alternative approach to therapy for Cooley's anemia. While intravenous compounds have been effective in inducing short-term increases in fetal hemoglobin in a few patients, long-term elimination of transfusion requirement has not been reported. In patients with Cooley's anemia, treatment with oral sodium phenylbutyrate alone, sodium phenylbytyrate combined with hydroxyurea, and hydroxyurea alone, has augmented fetal hemoglobin production and increased total hemoglobin concentration as much as 5 g/dl over baseline eliminating transfusion requirement in two patients. Parallel declines in circulating nucleated red cell count, and concentrations of serum transform receptor and erythropoietin, are consistent with more effective erythropoiesis. Over extended periods of treatment, no induction of other fetal proteins and no adverse effects were observed. Particular disease mutations and other genetic factors may be of prime importance in determining the response to agents that induce production of fetal hemoglobin.

Adult↗

Technical note: improved DNA extraction from ancient bones using silica-based spin columns.

We describe a simple method for extracting polymerase chain reaction-amplifiable DNA from ancient bones without the use of organic solvents. Bone powders are digested with proteinase K, and the DNA is purified directly using silica-based spin columns (QIAquick3, QIAGEN). The efficiency of this protocol is demonstrated using human bone samples ranging in age from 15 to 5,000 years old.

Animals↗