X-linked Emery-Dreifuss muscular dystrophy with lamin A deficiency and IBM inclusions.

The study demonstrates a 12-year-old patient with progressive proximal muscle weakness, joint contractures, rigidity of the neck, and absence of emerin and lamin A in the muscle nuclei, which is caused by intronic mutation IVS3-27del18 (c.266-27del18) in the emerin gene. The most surprising finding was the appearance of IBM-like inclusions in euchromatin, as well as aberrant nuclei. It may be speculated that altered expression of the emerin-lamin complex and modification of the nuclear matrix leads to formation of tubulofilamentous structures in the presented case.

Genetic refinement of the hereditary neuralgic amyotrophy (HNA) locus at chromosome 17q25.

Hereditary neuralgic amyotrophy (HNA) is an autosomal dominant, recurrent focal neuropathy. HNA is characterised by episodes of painful brachial plexus neuropathy with muscle weakness and atrophy, as well as sensory disturbances. Single episodes are commonly preceded by non-specific infections, immunisations or parturition. Mild dysmorphic features and short stature are present in some HNA families, but absolute co-segregation with HNA has not been described. To refine the previously described HNA locus on chromosome 17q25, we performed a genetic linkage study in five HNA families with different geographic origins. Significant linkage was obtained with chromosome 17q24-q25 short tandem repeat (STR) markers in three HNA families and suggestive linkage was found in the other two HNA families. Analysis of the informative recombinations in affected individuals allowed us to reduce the HNA linkage interval to a candidate region of 3.5 cM.

Further evidence supporting linkage of hereditary neuralgic amyotrophy to chromosome 17q.

Hereditary neuralgic amyotrophy is a rare autosomal dominant disorder of the peripheral nervous system. Previous segregation analysis in two large pedigrees suggested linkage to distal 17q. Linkage data obtained in the present study investigating a three generation pedigree confirm linkage to 17q24-q25.

Severe clinical expression in X-linked Emery-Dreifuss muscular dystrophy.

X-linked Emery-Dreifuss muscular dystrophy (EDMD) is a relatively rare benign neuromuscular disorder which can vary remarkably in onset, course and severity. In the present study, a TCTAC deletion spanning the nucleotides 631-635 of the emerin gene caused an unusually severe disease phenotype including loss of ambulation and severe muscle wasting in two affected brothers. The same mutation has been reported previously in an unrelated family showing a significantly milder phenotype. The interfamilial heterogeneity in distribution and in severity of the features in the two families point to environmental or genetic modification as the cause of clinical variability in Emery-Dreifuss muscular dystrophy.

Partial deletions of factor VIII gene as molecular diagnostic markers in haemophilia A.

A panel of 27 families at risk for haemophilia A was studied by RFLP analysis using the anonymous probe St14.1 (DXS52), a cDNA probe spanning the exons 16 to 19, and a genomic fragment of intron 22. In two patients with severe haemophilia A, who did not form inhibitors, abnormal RFLP patterns were found, that can be interpreted as partial deletions in exons 17 to 19, and intron 22, respectively. In a case with moderate haemophilia A a further partial deletion in intron 22 was found. The significance of the deletions detected as markers for pedigree analysis and prevention of haemophilia A is demonstrated.

Direct molecular genetic diagnosis and heterozygote identification in X-linked Emery-Dreifuss muscular dystrophy by heteroduplex analysis.

X-linked Emery-Dreifuss muscular dystrophy (EMD) is a very rare, relatively benign muscle disorder. The disease is associated with potentially lethal cardiac arrhythmias in affected males and some heterozygous females. X-linked EMD can be genetically distinguished from phenotypically similar autosomal EMD. Heterogenic mutations are identified as the cause of X-linked EMD. We introduced heteroduplex analysis to follow the segregation of heterogenic emerin gene mutations in the families of six unrelated EMD patients. Heteroduplex analysis was proved to be a simple, fast and reliable tool for direct molecular genetic diagnosis of EMD in male patients and identification of heterozygotes even in families where affected males are not available as index cases.

Deletion screening in patients with Duchenne muscular dystrophy.

DNA of 35 patients with Duchenne muscular dystrophy (DMD) from 27 unrelated families from the northern part of GDR, Czechoslovakia and Hungary were analysed by means of 9 genomic probes and cDNA probes Cf 23a and Cf 56a, which detect exons of the central part of the DMD gene. Of the unrelated DMD patients, 63% have deletions for one or more intragenic and/or cDNA probes and 33% have deletions for genomic probes, mostly for pERT 87 (15%) and P 20 (15%). 48% of the DMD patients have deletions for one or more exon regions detected by Cf 56a and Cf 23a. The deletions were mapped. The genomic probe P 20 and the distal part of the cDNA probe Cf 23a detected the same part in the centre of the DMD gene. The deletions are heterogeneous in size and extent. In patients of the same family, identical deletions were detected in the DMD gene. The detection of deletions is useful for prenatal diagnosis and carrier detection.

Cardiac responses to exercise in competitive child cyclists.

PURPOSE: Cardiovascular responses to exercise in highly trained child endurance athletes have not been well-defined. This study compared hemodynamic responses with progressive cycle exercise in seven competitive child cyclists (mean age 11.9 yr) compared with 39 age-matched untrained boys. METHODS: Doppler echocardiography and gas exchange variables were utilized to assess cardiovascular changes during submaximal and maximal exercise. RESULTS: Mean VO2max was 60.0 (+/-6.0) and 47.0 (+/-5.8) mL x kg(-1) x min(-1) in the cyclists and nonathletes, respectively. At rest and maximal exercise, the cyclists demonstrated greater stroke index than the untrained subjects (resting mean 59 (+/-6) vs 44 (+/-9) mL x m(-2); maximal mean 76 (+/-6) vs 60 (+/-11) mL x m(-2)), but the ratio of maximal:rest stroke index was similar in both groups (1.31 for cyclists, 1.41 for nonathletes). Both groups showed a plateau in stroke volume beyond low-intensity work levels. No significant difference was observed in maximal arteriovenous oxygen difference. CONCLUSIONS: These findings indicate that 1) maximal stroke volume is the critical determinant of the high VO2max in child cyclists and 2) factors that influence resting stroke volume are important in defining VO2max differences between child endurance athletes and untrained boys.

Characterization of three new deletions at the 5' end of the HPRT structural gene.

In a panel of seven unrelated HPRT-deficient patients three partial deletions of the 5' end of the HPRT structural gene were identified by Southern blot analysis. The deletions could be defined as the loss of exons 1-3, exons 2-3 and exon 3 respectively. In two of the deletion mutations aberrant restriction fragments occurred.

[Vitamin B 12 dependent methionine biosynthesis in pseudomonas aeruginosa]. / Vitamin B12-ABHANGIGE Methioninbiosynthese bei Pseudomonas aeruginosa

Among methionineless mutants of Pseudomonas aeruginosa strain PAO lacking the ability of methylating homocysteine we found two different types: One of them responding to methionine only, the other one to methionine or vitamin B12 alternatively. That means that P. aeruginosa PAO as well as other B12-producing bacteria (with one exception: Aerobacter aerogenes) use only the B12 pathway (metH) for methionine synthesis. The effect of some cys-auxotrophs equally growing on vitamin B12 as described by Calhoun and Feary (1969) was confirmed for P. aeruginosa PAO by our mutants. In a P. aeruginosa strain of other origin, PAE, neither met- nor cys-mutants responding to B12 have been found, although strain PAE as well as strain PAO excessively synthesize B12.

[Methods of chorion sampling for prenatal diagnosis in the 1st trimester of pregnancy. Report of experiences]. / Methoden der Choriongewinnung zur pränatalen Diagnostik im 1. Trimenon der Schwangerschaft. Erfahrungsbericht.

Report on first experiences in chorionic villi sampling in the first trimester of 131 pregnancies. Chorion biopsy was performed just before termination of pregnancy in the 9th-11th week of gestation. Of 3 tested biopsy methods we found the biopsy with a flexible forceps under guidance of real-time ultrasound to be the best.

Adenine therapy in Lesch-Nyhan syndrome.

In a 7-year-old patient with Lesch-Nyhan syndrome (LNS) the 15N excess frequency was determined in the excreted uric acid after oral application of 27 mg 15N glycine/kg body weight, using emission spectrometry. Incorporation of glycine into uric acid was considerably increased in untreated LNS in comparison with the control. This was due to the extremely increased endogenous de novo synthesis of purine. Allopurinol therapy caused only a gradual decrease of uric acid excretion. The pattern of purine excretion changed in favour of the better soluble oxipurines hypoxanthine and xanthine, by competitive inhibition of xanthine oxidase. In LNS, however, allopurinol had no uricostatic effect. Therapy with adenine is an alternative to influence the de novo synthesis. After adenine application a decrease of the cumulative 15N uric acid excretion occurs and the percentual proportion of 15N uric acid in total 15N excretion decreases. These changes are due to an inhibition of de novo purine biosynthesis. Adenine, however, must be applied in combination with allopurinol in order to avoid the formation of nephrotoxic 2,8-dioxiadenine by xanthine oxidase. Adenine therapy led to an improvement of the clinical course. No side-effects were observed.

Genomic diagnosis of haemophilia A and B in the German Democratic Republic.

Since 1986 the genomic diagnosis of haemophilia A and B in the GDR is realized as a national programme. Until Aug. 1989 56 families at risk of haemophilia A are analysed using RFLPs of different intragenic and intergenic probes (BclI/F8e 16-19, KpnI-XbaI/int 22, TaqI/St 14.1). 117 out of 162 females at risk being heterozygous were identified as carriers, in 40 cases the carrier state was excluded, and in 5 females the data were not informative. Prenatal diagnosis was offered to 93 carriers in reproductive age. Six genomic prenatal diagnoses in haemophilia A were performed. In four patients different partial deletions of factor VIII:C gene were found. 10 families of haemophilia B were analysed using intragenic and intergenic probes (P 1; pX58dIIIc). 14 females were identified as carriers, 11 were excluded. The application of direct and indirect gene diagnosis in haemophilia is discussed.

RFLP analysis for diagnosis of haemophilia A in the German Democratic Republic.

The frequencies of Bcl I, Hind III and Xba I intragenic polymorphic sites in the population of the GDR were found to be 0.68, 0.38 and 0.48, respectively. No differences in composition and frequencies were detectable at DXS 52 locus in comparison with other Caucasian populations. A strong linkage disequilibrium between the intragenic Bcl I and Hind III sites could be confirmed. The observed heterozygosity for the flanking marker DXS 52 in combination with intragenic Bcl I and Xba I polymorphisms was 0.97. Using these three RFLPs, 122 females at risk in 41 independent haemophilia A families were investigated; 86 of them could be identified and 27 excluded as carriers; 9 females could not be classified. So far, four prenatal diagnoses in the first trimester of gestation have been performed by RFLP analysis.

Deletion screening and prenatal diagnosis of Duchenne muscular dystrophy using cDNA probes Cf 23a and Cf 56a.

We have screened patients of 14 families at risk for Duchenne muscular dystrophy (DMD) from the northern part of the German Democratic Republic using the cDNA clones Cf 23a and CF 56a. Of the 14 unrelated DMD families, 7 (50%) showed different deletions with these cDNA probes. A prenatal diagnosis by chorionic villi sampling was performed in a DMD family with patients showing a deletion of the 5.4 kb Pst I band detected by the cDNA probe Cf 56a. This band corresponds to a 10 kb exon region of the cDNA probe 8 of Koenig et al. The patient's mother was informative only for the flanking marker 99.6. The male fetus showed the same haplotype and the same deletion as the two patients.