The importance of ß globin deletion analysis in the evaluation of patients with ß thalassemia.

INTRODUCTION: Beta globin deletion/duplication analysis may serve as a useful adjunct to sequence analysis. Our purpose was to develop a robust assay for beta globin deletion/duplication analysis and determine its role in evaluating patients with beta thalassemia. METHODS: A single tube semi-quantitative fluorescent PCR assay capable of detecting deletions and duplications in the beta globin cluster and the associated locus control region (LCR) was developed and validated. RESULTS: Six hundred seventy one de-identified samples submitted for beta globin sequence analysis were tested for deletions and duplications of the beta globin cluster. Twenty-two deletions were detected (3%, 22/671). Seventeen of the 22 (82%) deletion samples were negative for mutations in the whole gene sequencing assay. For 5 of the samples, homozygous point mutations were inferred by beta globin sequencing. Among the deletions detected, 11 (50%) involved only the beta globin gene (5 covering the entire gene, 2 spanning the 5' end of the gene and 4 encompassing the 3' end of the gene). Ten samples (45%) were heterozygous delta-beta deletions spanning both the delta globin and beta globin genes. One patient with a single deletion had Hb Lepore. CONCLUSION: Beta globin deletion/duplication analysis is necessary to correctly identify the genotype in some patients being evaluated for beta thalassemia.

Occurrence of common and rare δ-globin gene defects in two multiethnic populations: thirteen new mutations and the significance of δ-globin gene defects in ß-thalassemia diagnostics.

INTRODUCTION: The aim of this review is to study the frequency of common and the occurrence of rare and novel mutations of the delta-globin gene and of Hb Lepore defects that might interfere with thalassemia diagnostics and to report the rationale of HbA2 estimation in the presence of delta- or alpha-gene mutations. METHODS: A total of 135 cases suspected to have a delta-globin gene defect collected in a diagnostic center in the USA and in a reference laboratory in the Netherlands were characterized by molecular analysis. RESULTS: Hb B2 was found at a frequency of at least 0.5% in the USA and 0.87% in the Netherlands. Known variants such as Hb A2-Babinga, Hb A2-Sphakia, Hb A2-Fitzroy, Hb A2-Flatbush, Hb A2-NYU, Hb A2-Grovetown, HbA2-Yialousa, Hb A2-Indonesia and several delta-thalassemia mutations were found together with 13 new mutations and two new polymorphisms, while Hb Lepores were regularly observed. CONCLUSION: HbA2 mutations either structurally stable and visible or undetectable because of a thalassemia effect or instability are clinically asymptomatic but may compromise the diagnosis of beta-thalassemia minor. Stable mutations result in two HbA2 fractions of about half of the expected value. Expression defects are undetectable as a protein fraction but reduce the amount of HbA2 by half.

Heterotopia of gastric mucosa and liver involving the gallbladder. Report of two cases with literature review.

Two cases of heterotopic tissue involving the gallbladder are presented (one gastric mucosa, the other liver), and the relevant literature is reviewed highlighting problems in differential diagnosis and complications, particularly with regard to gastric mucosal heterotopia. A firm diagnosis of gastric heterotopia is based on the presence of fundic mucosa replete with parietal and chief cells; a clear distinction from intestinal metaplasia should be made, but at times may be difficult. Potential complications include mucosal ulceration, obstruction, and hemorrhage. Of 39 patients presented, about half were 30 years of age or younger, and only nine have had calculi noted in the cholecystectomy specimen. Heightened awareness of gastric heterotopia with separation of smooth-muscle bundles may help to avoid a malignant diagnosis. Hepatic tissue involving the gallbladder that is completely separate from the main part of the liver is an even rarer form of heterotopia that should be distinguished from an accessory lobe.

Relationships between patterns of acetylcholinesterase activity and geniculocortical terminal fields in developing and mature rat visual cortex.

Intraocular injections of wheat germ agglutinin conjugated to horseradish peroxidase (WGA-HRP) result in anterograde transneuronal labeling of geniculocortical axon terminals in cortical area 17. In area 17 of developing rat pups, transported WGA-HRP occurs primarily in layer I and in a band that includes layer IV and deep layer III; this pattern is virtually identical to the laminar pattern of endogenous acetylcholinesterase (AChE) activity. In adult animals, transported WGA-HRP again is localized in layer I and in deep layer III and layer IV, but the endogenous AChE activity is found most prominently in deep layer IV and layer V. These results indicate that geniculocortical terminal fields are co-extensive with transient patterns of AChE activity in the developing rat, but not with the mature pattern of AChE in the adult.