The use of DNA markers for carrier detection and prenatal diagnosis of haemophilia A in Egyptian families

Haemophilia A is the most common inherited X-linked recessive bleeding disorder. The aim was to investigate the usefulness of two DNA markers in linkage analysis, one intragenic BCL1 affecting restriction site in intron 18, and is detected as restriction fragment length polymorphism (RFLP), and one extragenic variable number of tandem repeat (VNTR) locus DXS52 (St14) to formulate an informative and accurate carrier detection and prenatal diagnosis. The study included 46 families with at least one child affected with haemophilia A, and 30 unrelated normal females as control group. Polymerase chain reaction (PCR) and restriction enzyme analysis were used to study the polymorphism in BCL1, and long-distance PCR for detection of VNTR (ST14) alleles. The incidence of BCL1 (+) allele was 74%, 72% and 60% in patients, mothers and control group, respectively. Expected heterozygosity for BCL1 was 40% in mothers of affected cases compared with 48% in the female control group. However, observed heterozygosity was found to be 48% in the mothers of affected cases, compared with 60% in the control group. Thus, 48% of the studied families are informative for this marker alone. Nine different alleles of VNTR (St14) were observed in mothers and six alleles in affected cases and six in the control group. The most prevalent alleles were 1300 bp (45.5% and 34%) and 700 bp (13.6% and 20%) in patients and their mothers, respectively. Observed heterozygosity in mothers was 41% compared with 43.3% in controls. The combined use of both BCL1 and St14 markers raised the informative rate to 63.6%. Carrier detection and prenatal diagnosis is possible in haemophilia A families using both DNA markers. We suggest screening haemophilic families first for BCL1 polymorphism followed by analysis of St14 locus.

Enzyme replacement therapy and bony changes in Egyptian paediatric Gaucher disease patients

BACKGROUND

In Gaucher disease, the infiltration of the bone marrow by glucocerebroside-laden macrophages (Gaucher cells) triggers a diverse pattern of skeletal disease that results in crippling complications. Reliable ascertainment of the severity and pattern of skeletal disease is essential to determine disease status and the response to enzyme replacement therapy (ERT). Although there is ample documentation of reversal of haematological and visceral disease by ERT, there is a paucity of data on skeletal response to ERT in children.

AIM

To delineate the pattern of bone disease in children with Gaucher disease in Egypt and to evaluate its response to ERT.

METHOD

Twenty-two children with Gaucher disease were treated with ERT. Phenotyping by clinical, laboratory and radiological criteria was performed at baseline and following 11.2 +/- 4 months of ERT. Genotyping for glucocerebrosidase (GBA) mutations was performed by gene sequencing, and genotype-phenotype correlations were performed.Results. Two-thirds of the patients were from consanguineous pedigrees and 14/22 patients were homozygous or compound heterozygous for L444P and D409H mutations. Bone involvement was detected by plain radiology in 11 children (50%) and in 16 (73%) by magnetic resonance imaging (MRI). There was no correlation of severity of bone involvement and GBA genotype. ERT ameliorated bone disease: 10 of the 11 children with abnormal radiographic findings at baseline showed improvement in skeletal lesions; while 9/16 showed improvement of marrow disease by MRI. Radiographic sensitivity and specificity were 62% and 82% compared to MRI for detection of bone involvement in this patient population. At baseline, bone pain was present in 5 patients and ERT resulted in complete symptomatic remission in all of them. ERT was associated with significant improvement in growth parameters and amelioration of haematological and visceral involvement.

CONCLUSION

Symptomatic and radiological skeletal disease is common in children with Gaucher disease in Egypt. MRI is the most accurate technique for detecting early skeletal involvement. There was no correlation between severity of skeletal involvement and GBA genotype. ERT was effective in ameliorating radiological manifestations of skeletal disease and achieving complete remission of bone pain.

Suitability of soluble transferrin receptor for the clinical diagnosis of different types of anaemia in children

We evaluated the ability of serum transferrin receptor [sTFR] to identify different types of anaemia in children. Thus 150 Egyptian children suffering from anaemia [iron deficiency anaemia, anaemia of chronic disease and beta-thalassaemia] were enrolled, together with 50 controls. There was a significant increase in the mean levels of sTFR in the groups with iron deficiency anaemia and thalassaemia, and a significant decrease in mean sTFR levels in the group with anaemia of chronic disease. Serum ferritin levels were significantly higher in all patient groups except the group with iron deficiency anaemia. There were also significant correlations between the sTFR and sTFR/log ferritin ratio [sTFR-F index] and different indices of iron status and of erythropoiesis. The sTFR-F index could be used as a diagnostic or screening tool for iron deficiency anaemia, anaemia of chronic disease and thalassaemia.

Suitability of soluble transferrin receptor for the clinical diagnosis of different types of anaemia in children

We evaluated the ability of serum transferrin receptor (sTFR) to identify different types of anaemia in children. Thus 150 Egyptian children suffering from anaemia (iron deficiency anaemia, anaemia of chronic disease and beta-thalassaemia) were enrolled, together with 50 controls. There was a significant increase in the mean levels of sTFR in the groups with iron deficiency anaemia and thalassaemia, and a significant decrease in mean sTFR levels in the group with anaemia of chronic disease. Serum ferritin levels were significantly higher in all patient groups except the group with iron deficiency anaemia. There were also significant correlations between the sTFR and sTFR/log ferritin ratio (sTFR-F index) and different indices of iron status and of erythropoiesis. The sTFR-F index could be used as a diagnostic or screening tool for iron deficiency anaemia, anaemia of chronic disease and thalassaemia.