[Survey on genetic counseling and health management for symptomatic and asymptomatic female dystrophinopathy carriers in Japan today]

Medical Attitudes Survey for Female Dystrophinopathy Carriers in Japan

Objective This study attempted to clarify the current status of female dystrophinopathy carriers, including the numbers of patients, the status of genetic screening, the status of counseling, physicians' understanding, and barriers to registration. Methods We sent out questionnaires to 402 physicians registered in the Remudy dystrophinopathy registry. The total number of responses received was 130 (response rate: 32%). Result In total, 1,212 cases of Duchenne muscular dystrophy, 365 cases of Becker muscular dystrophy, and 132 cases of female dystrophinopathy with a confirmed genetic mutation were encountered, and genetic testing was performed in the mother in 137, 23, and 12 cases, respectively. With respect to the risk of the onset of health problems, 25% of physicians always explained, 29% usually explained, 29% sometimes explained, and 13% never explained the risk to the mothers and female siblings of dystrophinopathy patients. The most common reason for not explaining the risk was a lack of knowledge/information. Thirty-five percent were familiar with the guidelines for testing the heart function of carriers. Conclusion Fewer mothers of dystrophinopathy patients have undergone genetic testing in Japan than in other countries. A significant portion of doctors did not explain the risks of health problems due to a lack of knowledge. We hope this survey will lead to an increased discussion of female dystrophinopathy patients.

Female dystrophinopathy: Review of current literature

Skeletal muscle or cardiac symptoms are known to appear in a certain proportion of female patients carrying the dystrophin gene mutation. There is limited high-quality evidence to guide the treatment of female carriers of Duchenne muscular dystrophy/Becker muscular dystrophy (DMD/BMD). The available evidence is mainly based on expert opinions and clinical experience. To improve this situation, we reviewed 1002 reports published from 1967 to 2017 to assess the following themes: epidemiology, clinical symptoms, cardiomyopathy, burdens on parents or caregivers, pregnancy or delivery, and prognosis. We aimed to provide guidance for the provision of support, care, and education for patients, caregivers, and health care professionals. There were 271 reports before 1987, and 731 reports after 1987 when dystrophin was first recognized. In this review, we mainly selected 37 papers that were reported after 1987. In seven large research papers, the incidence of skeletal muscle damage among female carriers, including asymptomatic carriers, was reported as 2.5%-19%, and the incidence of dilated cardiomyopathy was 7.3%-16.7% for DMD and 0%-13.3% for BMD. We integrated and summarized the genetically definite manifesting carriers with skeletal muscle symptoms from 10 case series. In combined data, among 93 manifesting carriers, 16 (17.2%) presented with cardiac abnormalities. The frequency of manifesting carriers complicated by cardiomyopathy increased with age. Reports on cardiac magnetic resonance in female carriers and the burden on caregivers are increasing, whereas literatures concerning pregnancy, delivery, and prognosis in female carriers are limited. This represents a future direction for research.