Biomedical subjects
Publications and source records attributed to T Grimm.
The prior probability of any woman being a carrier for Becker muscular dystrophy (BMD) has been calculated. If mu is the mutation rate in female germ cells and v the mutation rate in male germ cells, this probability is 34/3 mu + 20/3v. For all X-linked diseases with a fitness f the prior probability (H) is: (formula; see text).
A frequent problem of genetic counseling in Becker muscular dystrophy (BMD) is the differential diagnosis between BMD and the autosomal recessive benign limb-girdle muscular dystrophy (LGMD) if the pedigree pattern is not typical of X-linkage. In this situation, the a priori probability that a woman and her husband may be heterozygotes for LGMD can be shown to be 80 mu/a (mu = mutation rate in BMD; a = incidence ratio between BMD and LGMD). In addition, the age-corrected serum creatine kinase (CK) values of all female relatives are also important for the risk calculation of a woman being carrier of BMD.
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Trisomy for 7q32 leads to 7qter and monosomy for 9p24 leads to 9pter is observed in a sister and a brother, due to a balanced reciprocal translocation between the long arm of the chromosome 7 and the short arm of the chromosome 9 in the mother. The siblings are retarded mentally as well as in statomotoric development. This paper discusses the correlation between chromosomal states and certain deformities in patients with trisomies of different segments of 7q.
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Cross-sectional and concurrent M-mode echocardiograms of the left ventricular outflow tract and the ascending aorta were performed in 80 patients with supravalvar aortic stenosis (SVAS) selected from a total of 178 patients in whom the diagnosis had been established earlier by cardiac catheterization and angiocardiography. Visualization of the area of obstruction was possible in 77 patients using the cross-sectional system. In 34 cases recatheterization and angiocardiography of the left heart were carried out. To quantitate the severity of obstruction we used the pressure difference across the stenosis and the ratio of the cross-sectional areas at the level of the aortic annulus and of maximal supravalve stenosis. These cross-sectional areas were estimated from values for aortic diameter derived from scans in the long axis of the aorta, assuming the cross-sections to be circular. There was a good correlation between the ratios calculated from the echocardiogram and those calculated from the angiocardiogram (r = 0.894, n = 34, 0.747 less than p greater than 0.938). There was also a good correlation between the ratio of the surface areas calculated from the echocardiogram and the corresponding measured pressure differences (r = 0.932, n = .36, 0.878 less than p greater than 0.973). This study shows that cross-sectional echocardiography may be useful for estimating the severity of obstruction in SVAS.
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Clinical and cytogenetic examinations were performed on eight unrelated infants with duplication of part of the long arm of chromosome 3. A review of published cases shows a clinical syndrome characterized by statomotoric retardation, shortened life span, and a multiple congenital anomalies (MCA) syndrome of abnormal head configuration, hypertrichosis, hypertelorism, ocular anomalies, anteverted nostrils, long philtrum, maxillary prognathia, down-turned corners of the mouth, highly arched or cleft plate, micrognathia, malformed auricles, short, webbed neck, clinodactyly, simian crease, talipes, and congenital heart disease. The dup(3q) syndrome is a clinically easily recognizable entity.
The technique of screening for Duchenne muscular dystrophy (DMD) is a fairly simple procedure. However, the DMD is an untreatable disease. The advantage of screening is only to prevent other cases of DMD by genetic counselling of families to avoid a second, affected child. the estimated effectiveness of the screening is the prevention of 8,3-15% of the hemizygotes. The false negative cases in screening for carrier detection is 30%. (cut-off-level 120 IU/1). Therefore: No screening for carrier detection, voluntary screening in all newborn males and screening in families at risk and in all boys with potential early signs.
Three families with the syndrome of hereditary prolonged QT interval affecting 12 members in two or three generations are described. Four patients with sinus bradycardia and frequent syncopal attacks were investigated by Holter-monitoring, His-bundle electrograms and exercise testing. Corrected QT intervals (QTc) were prolonged from 0.43 to 0.54 seconds at rest. In His-bundle electrograms, during atrial pacing at increasing rates the function of the entire conduction system seemed to be affected. Three patients were treated with pindolol and one patient with a permanent demand pacemaker and pindolol. During progressive exercise testing performed after drug therapy or pacemaker treatment, heart rate increased unsatisfactorily and QTc-intervals lengthened whereas atrial stimulation QTc-intervals remained unchanged. In the patient with a permanent demand pacemaker, electrocardiographic monitoring revealed a period of 25 seconds of ventricular tachycardia occurring at rest and ceasing spontaneously. In the past 1.2 years to 2.5 years (mean 2.1 years) of outpatient follow-up, the patients had normal exercise tolerance and syncopal attacks did not occur on pindolol 30 mg/day. Our findings suggest rather a hypersensitivity of the affected conclusion system in the presence of a normal activity of cardiac sympathetic nerves.
The clinical findings of 150 patients with supravalvular aortic stenosis are presented. No correlation was found between the clinical findings and the hemodynamic degree of severity, with the exception that an ECG of left ventricular hypertrophy and strain was more common in patients with a LV pressure above 200 mm Hg. In this latter group of patients there is a significantly higher number of patients without the typical appearance of the Williams-Beuren syndrom. The analysis of the additional anomalies and mental retardation in the Williams-Beuren syndrom and the isolated cardiac lesion shows clearly that no distinct separation between these 2 groups is possible. This points towards the same pathogenesis.
45 patients with supravalvular aortic stenosis (SVAS) were investigated by cross-sectional echocardiography from a total number of 164 patients observed in Göttingen. In 44 cases the diagnosis of SVAS could be confirmed by this noninvasive method. There was a good correlation between the ratio of the echo-circular surface (aortic anulus and the point of maximal obstruction) and the ratio of the angio-circular surface, as well as the ratio of the echo-circular surface and the measured pressure gradient. Cross-sectional echocardiography is therefore a valuable noninvasive method for evaluating SVAS and for estimating the severity of obstruction.
For the localization and quantification of arterio-venous shunts of the heart and great vessels, accurate definition of the degree of oxygen saturation of venous blood in the venae cavae, right heart and pulmonary artery is essential. Hitherto only a few investigations in a small number of healthy subjects were published. Extensive investigations to define normal mixed venous blood in infants and children are unknown. This presentation is an analysis of the data on oxygen saturation of venous blood in 305 healthy children or patients with insignificant cardiac defects. Shunt lesions were excluded. A comparison of several formulae used to estimate the oxygen saturation of mixed venous blood from caval samples has been made. The sources of error in the estimation of mixed venous blood and the implications for the calculation of the shunt-volume are investigated in 122 patients without cardiac defects. The mean oxygen saturation from the right ventricle most nearly approached the mean oxygen saturation of the pulmonary artery whereas high inferior vena cava saturations correlated poorly with mixed venous blood. Superior vena cava, the mean oxygen saturation of the right atrium and the formula 3 x SVC + HIVC divided by 4 = MVB (where SVC is superior vena cava, HIVC is high inferior vena cava MVB is and mixed venous blood) gave a satisfactory regression and have nearly the same value for prediction of mixed venous blood.
Supravalvular aortic stenosis (SVAS) was seen in 128 families. In 23 families several members had SVAS. In 4 families the Williams-Beuren Syndrome (WBS) was present whereas members of 8 families had some features of the syndrome in addition to their cardiac lesion. In conclusion, no distinct separation can be made between WBS and SVAS. The genetic pattern is autosomal dominant with variable expressivity. The gene frequency is estimated at 10(-4) and the mutation rate at 2.5 . 10(-5).
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