[The RFLP of LDR152/PstI in the Chinese and its application to linkage analysis in a myotonic dystrophy family].

Myotonic dystrophy (DM) is inherited as an autosomal dominant trait and is characterized by variable expressivity and late age-of-onset. In the present paper, the DNA from 61 normal individuals and a DM family with 15 members of 4 generations were collected and digested with PstI, then hybridized with the LDR152 (D19S19). The results showed that the alleles for the PstI polymorphism were 19 and 11kb in size (gene frequencies were 0.4344 and 0.5656 respectively, which are obviously different from the previous data reported). In this DM family, the carriers who had lived most of their life without knowing that they had been infected with the disease were detected by the LDR152 and the estimation of DM risk on at-risk-individuals was also calculated.

[Diagnostic value of magnetic resonance imaging for syringomyelia].

Ten cases of syringomyelia confirmed by magnetic resonance imaging (MRI) were presented. The cavities in the spinal cord were of low signal on T1 weighted image (T1WI) and high signal on T2 weighted image (T2WI). The segments of the spinal cord with involved lesion resembled "bamboo joints" or were of "beaded" shape on sagittal section image and of "necklace" shape on cross section image. Size of the lesions in the spinal cord shown by MRI was larger than that judged by clinical symptoms. MRI can clearly show the position, size and shape of the cavities and other abnormal conditions. Results of this study show that MRI is the most useful diagnostic tool for syringomyelia. It should be emphasized that there was no dissociated impairment of pain and temperature and touch sensation in 40% of the patients and chronic spontaneous segmental pain was one of the important clinical characteristics of syringomyelia.