Gene mapping in Gypsies identifies a novel demyelinating neuropathy on chromosome 8q24.

Founder effect and linkage disequilibrium have been successfully exploited to map single gene disorders, and the study of isolated populations is emerging as a major approach to the investigation of genetically complex diseases. In the search for genetic isolates ranging from Pacific islands to Middle East deserts, the 10 million Gypsies resident in Europe have largely escaped the attention of geneticists. Because of their geographical ubiquity, lack of written history and the presumed social and cultural nature of their isolation, Gypsies are construed as not meeting the criteria for a well defined founder population. Gypsy society has a complex structure with subdivisions and stratifications that are incomprehensible to the surrounding populations. Marginalization by the health care systems in most countries results in a lack of information on causes of morbidity and mortality and little is known about hereditary disorders or the population genetic characteristics of Gypsies. This study is the first example of mapping a disease gene in endogamous Gypsy groups. Using lod score analysis and linkage disequilibrium, we have located a novel demyelinating neuropathy to a narrow interval on chromosome 8q24. We show that the disease, occurring in Gypsy groups of different identity and history of migrations, is caused by a single mutation whose origin predates the divergence of these groups.

Schwartz-Jampel syndrome: clinical, electromyographic and genetic studies.

Two sisters aged 9 and 7 from consanguineous parents are described. Both of them develop myotonia, muscular weakness as early as the first year after birth. At the age 3-4 a disturbed gait appeared due to knee joint contractures and limited joint movements. The children display facial dysmorphism (a small forehead, a flat base of the nose, a receding chin, an irregular order of the teeth, low-set ears, a high-arched palate, low hair-line), kyphoscoliosis, pigeon breast, severe contractures of the knee and elbow joint and foot deformities. The elder sister cannot walk. Hirsutism of all four limbs is found as well as sparse subcutaneous tissue. Muscles are stiff and firm. Tendon reflexes of the lower limbs are absent. Muscle enzymes show slightly increased values. The EMG needle examination in both sisters was abnormal. Spontaneous, continuous, high-frequency, low-voltage electrical discharges were observed in all distal and proximal muscles of the hands and legs. Some of them have a typical myotonic pattern. The MCV and the SCV was within the normal range. Both parents of our patients, their sister aged 4, as well as their grandparents showed no clinical and EMG abnormalities. All these data allow authors to affirm the diagnosis chondrodystrophic myotonia.

Schwartz-Jampel syndrome: clinical, electromyographic and genetic studies.

Two sisters aged 9 and 7 from consanguineous parents are described. Both of them develop myotonia, muscular weakness as early as the first year after birth. At the age 3-4 a disturbed gait appeared due to knee joint contractures and limited joint movements. The children display facial dysmorphism (a small forehead, a flat base of the nose, a receding chin, an irregular order of the teeth, low-set ears, a high-arched palate, low hair-line), kyphoscoliosis, pigeon breast, severe contractures of the knee and elbow joint and foot deformities. The elder sister cannot walk. Hirsutism of all four limbs is found as well as sparse subcutaneous tissue. Muscles are stiff and firm. Tendon reflexes of the lower limbs are absent. Muscle enzymes show slightly increased values. The EMG needle examination in both sisters was abnormal. Spontaneous, continuous, high-frequency, low-voltage electrical discharges were observed in all distal and proximal muscles of the hands and legs. Some of them have a typical myotonic pattern. The MCV and the SCV was within the normal range. Both parents of our patients, their sister aged 4, as well as their grandparents showed no clinical and EMG abnormalities. All these data allow authors to affirm the diagnosis chondrodystrophic myotonia., described for the first time in Bulgaria.

[Effect of captopril on the plasma aldosterone response to metoclopramide in normal subjects]. / L'effet du captopril sur la réponse de l'aldostérone plasmatique à la métoclopramide chez des sujets normaux.

The effect of captopril on the response of plasma aldosterone (PA) and plasma renin activity (PRA) to 10 mg metoclopramide i.v. was studied in 9 normal subjects. In the same conditions the prolactine response was studied in 6 healthy males. Metoclopramide induced a significant increase of PA during control study, as well as after treatment with captopril. The maximal increase of PA was of similar magnitude and occurred 15 mn after injection of metoclopramide on both occasions. PRA did not change appreciably after metoclopramide neither during control study nor during captopril. The prolactin response to metoclopramide was blunted by treatment with captopril. In conclusion, captopril did not alter the aldosterone response to metoclopramide, which suggests that dopaminergic control of aldosterone secretion is independent of modifications in the renin-angiotensin system.