A Boy with Holt-Oram Syndrome Caused by Novel Mutation c.1304delT in the TBX5 Gene

Holt-Oram syndrome (HOS) is an autosomal dominant developmental defect involving preaxial radial ray upper limb deformity and variable cardiac defects. It has been demonstrated that HOS is caused by mutations in the T-box transcription factor gene TBX5. Numerous germline mutations (more than 60) of this gene produce preterminal stop codons, which lead to synthesis of a truncated nonfunctional TBX5 protein. The haplo-insufficiency of the TBX5 gene is the most significant cause of HOS. We report on a sporadic patient with clinical features of HOS. Our patient had a cardiac anomaly - a muscular ventricular and atrial septal defect, patent ductus arteriosus and a conduction defect (a first-step atrioventricular block). Upper limb anomalies in our patient were relatively mild and unusual to HOS - distally displaced thumbs, narrow shoulders and hypotrophy of the muscles in the shoulder region. Molecular analysis identified a novel and unusual heterozygous frameshift mutation - c.1304delT (p.Leu435fsX146) - in exon 9 of the TBX5 gene, which is predicted to cause an elongated TBX5 protein with 84 miscoding amino acids and 62 supernumerary C-terminal amino acids. To the best of our knowledge, only one such type of elongation mutation has thus far been reported in the TBX5 gene.

High frequency of the HIV-1 protective CCR5 delta32 deletion in native Estonians

In previous studies, the highest frequencies (16%) of the CCR5 delta32 deletion have been found in populations of Finno-Ugric origin. We here report a high CCR5 delta32 frequency (15%) in another Finno-Ugric populations, the Estonians. The highest frequency (18%) was found on the geographically isolated Estonian island of Dagö. We examined 504 healthy unrelated individuals of Estonian nationality, whose grandparents were born in Estonia. The polymerase chain reaction assay was performed and the amplified products were digested with EcoRI.

A seven-years experience in treatment of childhood ALL in Bulgaria

After analyzing nonsatisfactory therapeutic results in the 1970s and early 1980s, the 81-01 treatment protocol of the Dana-Farber Cancer Institute was initiated in 1987 in the Children's Oncohaematology Clinic in Sofia, Bulgaria. Two hundred thirty patients were enrolled with a period of observation of a minimum of 14 and a maximum of 97 months; the median age was 5.83 +/- 3.6 years. According to the original criteria, standard risk (SR) patients were 38.26% and high-risk (HR) patients 61.74%. The probability for event-free survival at the seventh year estimated with the Kaplan-Meier method for the total group was 0.67 +/- 0.04 (+/- SE) and 0.55 +/- 0.09 and 0.81 +/- 0.06 for HR and SR, respectively (P < .001). Improvement of therapeutic results in terms of remission failures, early deaths, patients lost to follow-up, and rate of relapses is discussed.

Distribution of glutathione S-transferase T1 phenotypes in the Estonian population

The distribution of glutathione S-transferase T1 (GSTT1) phenotypes was studied in a total sample of 673 Estonians whose four grandparents were born in Estonia, by an ELISA test able to differentiate between GSTT1 positive and GSTT1 negative phenotypes. 18% of the total sample did not present GSTT1-1 protein in whole blood. GSTT1-1 concentration was assayed in 519 out of the 552 GSTT1 positive subjects (i.e. 82% of the total sample) 49% percent of this subsample made up by 519 subjects was found to have GSTT1-1 in intermediate concentration and 33% in high concentration. The gene frequency of the GSTT1 deleted allele was estimated to be 0.423 as the square root of the frequency of the GSTT1 negative subjects (square root of 0.18 = 0.423) and that of the GSTT1 positive allele as (1-0.423) = 0.577. Statistically significant regional differences were found within the population with the lowest frequency of GSTT1 negative in western Estonia (9.5%) and the highest in the southeastern part of the country (24.5%).