Thalassaemia intermedia in a family with beta 0-thalassaemia and Hb Hasharon.

A Brazilian family of Italian descent is described in which the beta-thalassaemia gene is interacting with an alpha chain variant Hb Hasharon (alpha 47 Asp leads to His). One patient who was affected by homozygous beta 0-thalassaemia and heterozygous alpha Hasharon displayed the clinical picture of thalassaemia intermedia. Her haemolysate contained 8.6% Hb F Hasharon (alpha 2 Hasharon gamma 2) and 1.1% Hb A2, the remaining haemoglobin being Hb F. Hb A was not detected. Globin chain synthesis in reticulocytes showed non-alpha/total alpha ratios of 0.29, 0.39, and 0.73 respectively for the patient, the mother, and the father, who is heterozygous for both the beta 0-thalassemia and Hb Hasharon genes. The possible contribution of Hb Hasharon heterozygosity to the less severe expression of homozygous beta 0-thalassaemia is discussed.     

Haemoglobin K Woolwich: a study of the family of a homozygote.

A family is described in which the proband is homozygous and several relatives are heterozygous for Hb K Woolwich (beta 130 [H10] Lys leads to Gln). These people are clinically and haematologically normal. The relationship between the presence of Hb K Woolwich and beta +-thalassaemia is discussed. The distribution of Hb K Woolwich in West Africa is discussed and it is seen to be closely associated with the Akan group.     

Haemoglobin E trait and probable alpha-thalassaemia in a black American family: a family study.

This is a report of haemoglobin E trait in a black American family with no known Asian ancestory. The father appears to be heterozygous for both haemoglobin E and alpha-thalassaemia. The mother is normal both clinically and haematologically. These children carry Hb E trait alone. The youngest son has a normal haemoglobin pattern and appears to have alpha-thalassaemia.     

The first observation of Hb D Punjab beta zero thalassaemia in an English family with 22 cases of unsuspected beta zero thalassaemia minor among its members.

A 36 year old local Englishman from Nuneaton was referred to hospital with suspected glandular fever. Relevant tests were negative and the symptoms subsided in due course. The finding of a hypochromic microcytic blood picture without iron deficiency led to the discovery that he was heterozygous for Hb D and beta thalassaemia. Hb D trait was established in the father of the proband and beta thalassaemia in his mother and a brother. The father's ancestors were miners who came to Nuneaton from Monmouthshire in the 19th century. The mother's ancestors have belonged to the indigenous population of Nuneaton and neighbouring Leicestershire since the 18th century. Twenty local members of her wider family also had thalassaemia. All thalassaemias had a low MCH and raised level of Hb A2. The Hb F level, however, was normal in five, demonstrating the independent segregation of genetic factors influencing the Hb F level in beta thalassaemia trait.     

Clinical, haematological, and genetic studies of type 2 normal Hb A2 beta thalassaemia.

The clinical and haematological phenotype as well as chain synthesis data were studied in 35 doubly heterozygous patients with either normal Hb A2 and Hb F, type 2 beta thalassaemia and beta (high A2) thalassaemia (26 patients), or type 2 and other rare beta or delta beta variants (nine patients). Patients doubly heterozygous for type 2 and beta zero or delta beta zero thalassaemia variants had no detectable Hb A, indicating that the type 2 normal A2 beta thalassaemia is primarily the result of a beta zero gene. The clinical phenotype varied from severe thalassaemia major to mild thalassaemia intermedia, and was mainly related to the thalassaemia variant with which the type 2 normal A2 beta thalassaemia was combined, and the proportion of Hb A produced in beta + thalassaemia patients. Haematological and chain synthesis data were similar in heterozygotes with type 2 and beta zero or beta + (high A2) thalassaemia. Hb A2 levels were within the normal range (2.3 to 3.6%) though absolute values (Hb A2 per RBC) ranged from low normal (0.5 pg/RBC) to increased levels (1.0 pg/RBC.) The variation of Hb A2, as well as the presence of Hb A2 in a type 2/delta beta high F patient and the complete absence of HbA2 in a homozygous type 2 patient, indicate that there are at least two genotypes of type 2, one beta zero and the other delta beta zero. This has been recently proven by gene mapping studies. For clinicians, routine haematological and family studies are sufficient for the proper treatment and prevention of doubly heterozygous type 2 patients.     

A possible bichromatid mutation in a male gamete giving rise to a female mosaic for two different mutations in the X-linked gene WAS

In genetic disorders caused by point mutations or small frameshift mutations, affected members of the same family are expected to have the same mutation in the causative gene. We have recently evaluated a family in which this was not the case. Maternal cousins with Wiskott-Aldrich syndrome (WAS; MIM 301000) had two different but contiguous single base pair deletions in WAS. The proband had an A deletion in codon 242 in exon 7 of WAS; his two cousins had a C deletion in codon 241. The mother of the proband was heterozygous for the A deletion allele, but her three sisters, including the mother of the affected cousins, were heterozygous for the C deletion. Both deletions occurred on the haplotype from the unaffected maternal great-grandfather. The maternal grandmother, who was a carrier of WAS, based on a non-random pattern of X chromosome inactivation in T cells, was mosaic for both deletions. These findings are most consistent with the mutations originating in a male gamete with different mutations on the two strands of DNA, a bichromatid mutation.     

X-linked Ehlers-Danlos syndrome type V; the next generation

Two English families with the X-linked form (Type V) of the Ehlers-Danlos syndrome (EDS) who were investigated almost 20 years ago have been re-studied. In one family, the potentially heterozygous sister of 3 affected brothers had born two sons, of whom one has EDS. The 3 brothers had all procreated, producing a total of 2 sons and 3 daughters, all of whom are clinically normal. These pedigree data provide further evidence to support the syndromic identity and X-linked mode of inheritance of this form of the EDS. In the second family, two affected brothers had both procreated; one had produced three normal offspring, while the other had a son with soft extensible skin and a daughter with articular hypermobility. The syndromic status of this kindred is uncertain. Serum copper and ceruloplasmin concentrations in affected males and obligate carrier females in both families were normal. Cytogenetic investigations, including high resolution banding, yielded normal results.     

Hb Q(India) and its interaction with beta-thalassaemia: a study of 64 cases from India

Haemoglobin Q (Hb Q), a relatively uncommon alpha-chain structural Hb variant, has been reported either in the heterozygous state or interacting with beta-thalassaemia. Individuals inheriting Hb Q generally are asymptomatic and are diagnosed by chance during population screening or as a part of a family study. This paper represents the first large study from India of 64 cases of Hb Q, documenting the haematological and molecular findings on 36 cases of Hb Q trait, 22 of Hb Q beta-thalassaemia trait and three of Hb Q beta-thalassaemia major, as well as a family of Hb Q homozygous cases. Hb Q is detected by Hb electrophoresis and chromatography. Hb Q levels in homozygous cases ranged from 32% to 35%, while in Hb Q heterozygotes the level was 20%. When there was an interaction of beta-thalassaemia heterozygotes the level was 14%, and in interacting beta-thalassaemia homozygotes the levels ranged from 7% to 9%. beta-thalassaemia mutations were characterised in cases showing elevated Hb A2 levels, which were markedly reduced in the majority of cases in which beta-thalassaemia was absent. Hb Q is rare and not a single homozygous case has been reported. However, Hb Q disease showed wide variation in clinical and haematological presentation in the same family.     

Double heterozygosity for hemoglobins C and Lepore in an American black man

We describe a patient doubly heterozygous for hemoglobin (Hb) C-Hb Lepore. To our knowledge, this is only the second case reported in the United States. The erythrocyte morphology and clinical findings were suggestive of Hb C-beta-thalassemia. Following Hb electrophoresis, the correct diagnosis was postulated and was subsequently confirmed by a reference laboratory. We also present the family pedigree of Hb abnormalities. The morphologic alterations of the erythrocytes presented in this article, when seen in conjunction with the distinctive electrophoretic pattern, should suggest the abnormality in undiagnosed cases.     

The fragile X syndrome: variability of expression in carrier females

The fra(X) expression in heterozygotes varies considerably from family to family. In family D23, 5 carriers express the fra(X) regardless of age. DNA studies using 3 markers were inconclusive as to whether cytogenetic testing is more reliable in this family than in others. III-2 and III-5 are the critical individuals in the pedigree; further study with closer probes should resolve this question.     

Clinical and haematological evaluation of beta thalassaemia intermedia characterised by unusually low Hb F and increased Hb A2: beta thalassaemia intermedia II.

A total of 15 patients from different families with thalassaemia intermedia was studied. Haematological studies showed that the fetal haemoglobin was only slightly raised, being between 2 and 11.5% of the total haemoglobin. Haemoglobin A2 was high in all cases. The family study indicated that homozygosity or compound heterozygosity for beta thalassaemia was present in five patients, while dominant inheritance was observed in three. In seven patients family studies were not sufficient to predict the genotype. Haematological findings in the parents of the homozygous patients were as severe as those seen in common Hb A2 beta thalassaemia traits. The decrease in MCH and MCV was more severe and the Hb A2 higher in homozygous patients than in cases of common beta thalassaemia major (p less than 0.01, p less than 0.01, and p less than 0.001 respectively). The imbalance in in vitro globin synthesis was more severe in classical beta thalassaemia major than in homozygous patients in this study (p less than 0.01). However, the imbalance in alpha/non-alpha synthetic ratios showed variation among the homozygous and heterozygous patients in this study (2.1 to 4.0). Haematological severity and Hb F value showed some slight variation among affected persons of the same family in the case of patients with severe beta thalassaemia heterozygosity. The G gamma/A gamma ratio of haemoglobin F was found to be close to that of the adult level. Haematological studies suggested that clinical and haematological findings were more severe in patients with homozygous beta thalassaemia than in patients with heterozygosity for beta thalassaemia. The prevalence of thalassaemia intermedia with low Hb F and increased Hb A2 was found to account for 3% of the Turkish beta thalassaemic patients diagnosed before the age of 8 years.     

ERG phenotype of a dystrophin mutation in heterozygous female carriers of Duchenne muscular dystrophy

PURPOSE: Mutations in the dystrophin gene result in Duchenne muscular dystrophy (DMD). DMD is associated with an abnormal electroretinogram (ERG) if the mutation disrupts the translation of retinal dystrophin (Dp260). Our aim was to determine if incomplete ERG abnormalities would be associated with heterozygous carriers of dystrophin gene mutations. METHODS: Ganzfeld ERGs were obtained under scotopic and photopic testing conditions from a family which includes the heterozygous maternal grandmother, the heterozygous mother, and her children, two affected boys and dizygotic twin sibs, an unaffected male and heterozygous female. Southern blot analyses were done to characterise the dystrophin mutation. RESULTS: The dystrophin gene was found to contain a deletion encompassing exon 50. The ERGs in the two affected boys were abnormal, consistent with the DMD ERG phenotype. Serial ERGs of the heterozygous females were abnormal; however, they were less severely affected than the DMD boys. The ERG of the female sib showed a greater abnormality than her mother and maternal grandmother. The unaffected twin had a normal ERG. CONCLUSIONS: The ERG shows abnormalities associated with carrier status in this family with a single exon deletion. A large study of confirmed obligate carriers is planned to clarify further the value of the ERG in detecting female heterozygous carriers of dystrophin gene mutations.     

Haemoglobin Lepore in Cyprus.

Structural analysis documented the presence of haemoglobin LeporeWashington (=LeporeBoston) in a Greek Cypriot family and provided further evidence that, of the various types of Lepore mutants, only one is common in the Mediterranean area. Two individuals in this family were heterozygous for both Hb Lepore and beta thalassaemia, but they exhibited striking differences in the clinical severity and course of the disease. The data illustrate that additional environmental or genetic factors play roles in determining or modifying the pathophysiological consequences of highly specific molecular defects and, thus, their ultimate clinical phenotypes.     

A second Australian family with hemoglobin North Shore (beta 134 Val----Glu)

A second Australian family is reported with Hemoglobin North Shore (beta 134 Val----Glu), an unstable hemoglobin, causing no clinical symptoms. All affected family members showed only mild reticulocytosis and microcytosis on the blood film, despite the strongly positive isopropanol test for Hb (hemoglobin) stability and numerous red cell inclusions. Hb North Shore constituted 31-38% of the total hemoglobin and migrated on the anodal side of Hb A at pH 8.9. The association of a mildly raised Hb A2 level and thalassemic phenotype with Hb North Shore previously reported, is confirmed in this study.     

Interference of hemoglobin Hope on beta-thalassemia diagnosis by the capillary electrophoresis Method

The β-chain hemoglobin (Hb) variants interfere with the diagnosis of β-thalassemia trait using high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE). We analyzed the effect of Hb Hope, a β-chain Hb variant frequently found in the Thai population, on β-thalassemia trait diagnosis. HPLC and CE were used to quantify the level of HbA(2) in 11 whole blood samples containing Hb Hope. The levels of Hb Hope detected by both methods were similar. An elevated HbA(2) level was found in all samples analyzed by the CE method, while 1 was increased when analyzed by HPLC, which was a compound heterozygous of Hb Hope and α-thalassemia-1 SEA-type deletion. Of 11 samples, 6 had mean corpuscular volumes within the reference range. All samples showed negative results for molecular analysis of β(0)-thalassemia codon 17, 41/42, and 71/72 mutations and β-thalassemia 3.5-kb deletion. Therefore, Hb Hope interfered with the diagnosis of β-thalassemia trait analyzed by CE but not by HPLC.     

Intergeneration CAG expansion and contraction in a Chinese HD family.

The prevalence of juvenile-onset Huntington's disease (HD) is about ten times lower than adult HD. Here we report a Chinese HD family showing both intergeneration CAG expansion and contraction. The expansion resulted from a paternal transmission which leads to juvenile-onset HD for a 17-year-old Chinese boy (III-5). More interestingly, a contraction was noticed in a maternal transmission (III-3), which changed the CAG repeat from an expanded, disease-causing allele (48 repeats) to a normal or intermediate allele (34 repeats). Of note, the contraction resulted in a deletion of 14 CAG repeats, which is much larger than previously reported contractions. Our results are consistent with previous observations in Western Caucasians that juvenile-onset HD is more likely inherited through the male germline.     

Immunologic studies of three family members with the immunodeficiency with hyper-IgM syndrome

We report the results of immunologic studies in a family in which the father (III-5) and his two daughters (IV-7 and IV-8) had the hyper-IgM syndrome (IHIS). Repeated immunoglobulin levels done on III-5 showed a typical IHIS pattern: low IgG, traces of IgA, and high IgM. IV-7, who also had stage IIA Hodgkin's disease, had a similar pattern except after irradiation therapy to sites of disease, when IgM dropped to normal range while IgG and IgA remained low. IV-8, on the other hand, had normal IgG and IgA and moderately elevated IgM until age 18 months, when she gradually developed the IHIS pattern. All three patients had normal numbers of B cells (sIg) and of T cells, although IV-7 had increased suppression. Finally, all three patients shared the A3,B7 haplotype and none was blood type O. IHIS is not necessarily X linked, is not associated with blood type O, and appears to be heterogeneous even within the same family. Inheritance in this family is apparently autosomal dominant and the father may represent a new mutation.     

Wilson disease. Comparative ultrastructure in a sibship of nine.

Comparative electron microscopy was done on liver tissue from a family of nine siblings to determine whether presymptomatic, affected patients with Wilson disease could be differentiated from heterozygous, normal carriers. Two of the nine had developed the neurologic manifestations of the disease; three others were considered to be homozygous but normal, two were heterozygous and normal, and two were classified as genotypically uncertain because of borderline biochemical abnormalities. Alterations of the mitochondria and endoplasmic reticulum suggestive of copper toxicity were present in both the heterozygous and the genotypically uncertain siblings, and a clear distinction could not be made on this basis. The severity of the abnormalities appeared to correlate with liver copper level, and organelle changes were found to precede lipid accumulation.     

Autosomal dominant myofibrillar myopathy with arrhythmogenic right ventricular cardiomyopathy 7 is caused by a DES mutation

Using exome sequencing we searched for the genetic cause of autosomal dominant myofibrillar myopathy with arrhythmogenic right ventricular cardiomyopathy (ARVC) in a Swedish family. A heterozygous C-to-T transition, c.1255C>T, p.Pro419Ser in the desmin gene on chromosome 2q35, was identified. Previous studies had demonstrated linkage to chromosome 10q22.3, but no causative mutation had been found in that region. Sanger sequencing of DNA from 17 family members confirmed the heterozygous c.1255C>T desmin mutation in seven out of ten family members that had been classified as affected in the previous study. Our new results demonstrate the usefulness of next-generation sequencing, and the diagnostic difficulties with some forms of dominantly inherited muscle diseases as they can display a wide clinical and morphological variability even within a given family.