A Woman with Missing Hb A2 Due to a Novel (εγ)δß0-Thalassemia and a Novel δ-Globin Variant Hb A2-Gebenstorf (HBD: c.209G>A).

A woman completely lacking Hb A2 on the high performance liquid chromatography (HPLC) analysis, presented with a novel deletional (εγ)δß0-thal and a δ-globin gene variant. This combination causes a ß-thalassemia (ß-thal) minor phenotype. The woman was referred by a hematologist due to abnormal blood counts. Multiplex ligation-dependent probe amplification (MLPA) and microarray analysis showed a heterozygous, 177 kb long deletion that removed the locus control region enhancer plus the ε, Gγ and Aγ genes. Additional sequencing revealed a novel variant HBD: c.209G>A, p.Gly70Asp in the heterozygous state, called Hb A2-Gebenstorf. The combination of the two variants explains the lack of Hb A2 in this woman.

Molecular characterization of Treponema pallidum subsp. pallidum in Switzerland and France with a new multilocus sequence typing scheme.

Syphilis is an important public health problem and an increasing incidence has been noted in recent years. Characterization of strain diversity through molecular data plays a critical role in the epidemiological understanding of this re-emergence. We here propose a new high-resolution multilocus sequence typing (MLST) scheme for Treponema pallidum subsp. pallidum (TPA). We analyzed 30 complete and draft TPA genomes obtained directly from clinical samples or from rabbit propagated strains to identify suitable typing loci and tested the new scheme on 120 clinical samples collected in Switzerland and France. Our analyses yielded three loci with high discriminatory power: TP0136, TP0548, and TP0705. Together with analysis of the 23S rRNA gene mutations for macrolide resistance, we propose these loci as MLST for TPA. Among clinical samples, 23 allelic profiles as well as a high percentage (80% samples) of macrolide resistance were revealed. The new MLST has higher discriminatory power compared to previous typing schemes, enabling distinction of TPA from other treponemal bacteria, distinction between the two main TPA clades (Nichols and SS14), and differentiation of strains within these clades.

Two novel α2 gene mutations causing altered amino acid sequences produce a mild (Hb Kinshasa, HBA2: c.428A > T) and severe (HBA2: c.342-345insCC) α-thalassemia phenotype.

We describe two novel α2 gene mutations that result in an altered amino acid sequence. In case 1, the α2 stop codon was mutated from TAA > TTA (HBA2: c.428A > T), resulting in an α2 protein chain extension of 31 amino acids. The new hemoglobin (Hb) variant was named Hb Kinshasa for the place of origin of the patient. This patient was also a carrier of Hb S (HBB: c.20A > T), which was expressed at reduced levels, but had an otherwise normal blood count. For cases 2 and 3, an α2 frameshift mutation caused a premature α2 protein chain termination at position 133 (HBA2: c.342-345insCC). The phenotype of this mutation seems to be rather severe as judged by the pronounced microcytosis and hypochromia observed in case 2. In addition, the father of this patient (case 3) also carried a ß(0)-thalassemia (ß(0)-thal) mutation (HBB: c.118C > T).

A new (G)γ-globin variant causing low oxygen affinity: Hb F-Brugine/Feldkirch [(G)γ105(G7)Leu→His; HBG2: c.317T>A].

In two unrelated families, several newborns developed cyanosis within the first days of life. For all of them, consecutive arterial blood gas analyses showed a right shift of the saturation curve, suggesting the presence of a hemoglobin (Hb) variant. A new (G)γ-globin variant was detected, namely (G)γ105(G7)Leu → His; HBG2: c.317T > A, that we named Hb F-Brugine/Feldkirch after the place of origin of the two families. This T to A conversion results in a leucine to histidine amino acid change at codon 105 of the (G)γ-globin gene and caused a Hb variant with lowered oxygen affinity. The γ to ß switch proceeded normally.

Neonatal cyanosis due to a new (G)γ-globin variant causing low oxygen affinity: Hb F-Sarajevo [(G)γ102(G4)Asn→Thr, AAC>ACC].

A baby girl, born at term, presented with severe cyanosis and received oxygen supplementation. Consecutive arterial blood gas analysis showed a pronounced right shift of the saturation curve, suggesting the presence of a hemoglobin (Hb) variant. A new (G)γ-globin variant was detected, namely HBG2:c.308G, which we have named Hb F-Sarajevo, the city from where the baby's parents originate. This A to C transversion exists in cis to the common (A)γ(T) and the resulting mutant Hb molecule exhibits very low oxygen affinity and cooperativity. Its analogue in the ß-globin gene is Hb Kansas [ß102(G4)Asn→Thr, AAC>ACC].

Comparison of two known chromosomal rearrangements in the 뫧-globin complex with identical DNA breakpoints but causing different Hb A(2) levels.

We report three cases with very heterogeneous Hb A(2) levels caused by known chromosomal rearrangements in the ß-globin locus. These rearrangements had their breakpoints at the same region in the δ gene, leading either to the Senegalese δ(0)ß(+)-thalassemia (δ(0)ß(+)-thal) deletion or to an insertion of a δ gene, known as Anti-Lepore. One patient showed, apart from drastically increased Hb A(2) values of 17.0%, inconspicuous hematological values. He had an Anti-Lepore mutation with three copies of the δ gene, thus explaining the high Hb A(2) level. Two other patients had Hb A(2) levels in the lower borderline range and increased Hb F levels. Molecular analysis showed the Senegalese δ(0)ß(+)-thal deletion. One of them presented with an additional mild ß-thal mutation leading to ß-thal intermedia. These cases illustrate that different gene rearrangements with the same breakpoints in the δ gene can lead to different levels of Hb A(2) depending on the remaining number of δ genes.

Characterization of three novel delta chain hemoglobin variants and two delta-thalassemia alleles.

We report the characterization of five novel delta-globin gene mutations detected during routine screening for thalassemia. Three missense mutations were identified, resulting in the following delta chain hemoglobin (Hb) variants: Hb A(2)-Acacias [delta4 (ACT>AGT), Thr-->Ser, HBD c.14C>G], Hb A(2)-Toronto [delta74 (GGC>GAC), Gly-->Asp, HBD c.224G>A], and Hb A(2)-Calgary [delta99 (GAT>GGT), Asp-->Gly, HBD c.299A>G]. Two other mutations most likely result in delta(0)-thalassemia (delta(0)-thal). One mutation altered the translation initiation codon from ATG to ATA (HBD c.3G>A), and another changed the canonical splice donor sequence of IVS-II from GT to AT (HBD C.315+1G>A).

alpha-Thalassemia caused by two novel splice mutations of the alpha2-globin gene: IVS-I-1 (G>A and G>T).

We report the identification of two different mutations involving the first nucleotide of intron 1 of the alpha2-globin gene: IVS-I-1 G-->A and G-->T. The available data indicated that both mutations reduce the efficiency of proper mRNA splicing, resulting in alpha(+)-thalassemia (alpha(+)-thal).

Three new beta-thalassemia mutations with varying degrees of severity.

We report the identification of three, new beta-thalassemia (beta-thal) mutations with varying degrees of severity. The most severe mutation, a frameshift mutation in exon 3 of the beta-globin gene [codon 120 (-A)], was associated with a dominant beta-thal phenotype. A second frameshift mutation, codon 50 (-T), resulted in a phenotype of typical high Hb A(2) beta-thal trait. The mildest mutation was IVS-II-2 (T > C), which changes the splice donor sequence of IVS-II from GT to GC. This transition mutation resulted in a slight reduction in beta-globin gene expression and could be considered a mild beta(+)-thal allele.

Compound heterozygosity for Hb S [beta6(A3)GluVal, GAG-->GTG] and a new thalassemic mutation [beta132(H10)Lys-->term, AAA-->TAA] detected in a family from West Africa.

We describe a Hb S/beta-thalassemia (beta-thal) mutation involving an AT transition at codon 132 of the beta-globin gene. The mutation, in the heterozygous state, unlike several other mutations in exon 3, shows no signs of dominant thalassemia but those of a typical beta(0) carrier. Compound heterozygosity with Hb S [beta6(A3)GluVal, GAGGTG] showed a severe clinical picture.

A 65 bp duplication/insertion in exon II of the beta globin gene causing beta0-thalassemia.

We describe a patient originating from Ghana who had combined heterozygous alpha (4.2)thalassemia, alpha alpha alpha anti3.7 triplication, the common delta globin variant HbA2' and a new 65 bp duplication/insertion in exon II of the b globin gene causing beta (0)-thalassemia.

A new electrophoretically silent beta-globin variant in a Portuguese family: Hb Viseu [beta57(E1)Asn --> Thr].

A new electrophoretically and clinically silent beta-globin variant has been detected by DNA analysis. The mutation was demonstrated at the protein level by reversed phase high performance liquid chromatography (HPLC) and electrospray ionization-mass spectrometry (ESI-MS).

Two new delta-globin mutations: Hb A2-Ninive [delta133(H11)Val-Ala] and a delta(+)-thalassemia mutation [-31 (A --> G)] in the TATA box of the delta-globin gene.

Two new delta-globin gene mutations have been detected: one leads to a fairly stable Hb A2 variant differing electrophoretically only minimally from normal Hb A2, and the second causes a delta(+)-thalassemia (thal) phenotype.

A new highly unstable alpha chain variant causing alpha(+)-thalassemia: Hb Zurich Albisrieden [alpha59(E8)Gly-->Arg (alpha2)].

A new alpha-globin mutation causing persistent mild hypochromic microcytosis and erythrocytosis is described. Hb Zurich Albisrieden [alpha59(E8)Gly-->Arg (alpha2)] is not detected at the protein level and leads to alpha(+)-thalassemia (thal).

Detection of Tropheryma whipplei DNA in feces by PCR using a target capture method.

Whipple's disease is a rare multisystemic bacterial infection with variable clinical manifestations. For decades, the laboratory diagnosis was based on the demonstration of periodic acid Schiff-positive inclusions in macrophages of gastrointestinal biopsies. PCR has improved the diagnosis of Whipple's disease due to its increased sensitivity compared to histopathological analysis. To avoid invasive procedures for taking specimens, we have investigated the possibility of detecting Tropheryma whipplei DNA in feces rather than in biopsies or gastric aspirate of patients with and without Whipple's disease. Total bacterial DNA was isolated from stool specimens using Qiagen columns followed by a T. whipplei-specific hybridization step with a biotinylated capture probe and streptavidin-coated magnetic particles. The captured DNA was then amplified using the same seminested PCR targeting the 16S rRNA gene of the organism that had been applied to other specimens without capturing. For five of eight patients with Whipple's disease, duodenal biopsies and stool samples were PCR positive, whereas for the three other patients, both specimens were PCR negative. Of 84 patients without Whipple's disease, 75 tested negative in the duodenal biopsy and in the stool sample. For four, both specimens were positive. Five patients tested positive in the stool sample but not in the biopsy. However, for three of these five patients, the gastric aspirate had been PCR positive, indicating that the stool PCR result was true rather than false positive. Compared to PCR from duodenal biopsies, stool PCR has a sensitivity of 100% and a specificity of 97.3%. Additionally, 15 PCR-positive and 22 PCR-negative stool samples were extracted using the Invisorb Spin Stool DNA kit. The simplified stool extraction showed 93.3% sensitivity and 95.5% specificity compared to the target capture method. We conclude that PCR with stool specimens with either extraction method is a sensitive and specific diagnostic tool for the detection of T. whipplei DNA and one not requiring invasive sampling procedures.