Preimplantation genetic diagnosis for myotonic dystrophy type 1: upon request to child

[Questionnaire surveys of clinical genetic specialists on the medical genetics for patients with myotonic dystrophy type 1]

We conducted nationwide questionnaire surveys of medical genetics for patients with myotonic dystrophy type 1 to certified medical geneticists. Explanations about the patient's problems were influenced by geneticist's specialties and central nervous system disorders. Many geneticists answered that male patients are also eligible for prenatal/preimplantation genetic diagnosis, and they perform prenatal genetic diagnosis for men if asked. About 40% of respondents answered that criteria for preimplantation genetic diagnosis should be relaxed. Thus, we investigated the implementation status of prenatal/preimplantation genetic diagnosis at the participating facilities of the national liaison council for clinical sections of medical genetics. No facility had an experience of prenatal/preimplantation genetic diagnosis for male patients. Still, one facility was applying for preimplantation genetic diagnosis. The social consensus of reproductive medicine is influenced by technological progress and historical background. It is essential to eliminate the eugenic's idea and form a social consensus through sufficient discussions with participants from many areas, including the patients and their families.

The impact of parental unaffected allele combination on the diagnostic outcome in the preimplantation genetic testing for myotonic dystrophy type 1 in Japanese ancestry

PURPOSE

The objective is to clarify the practical problem of the preimplantation genetic testing (PGT) for myotonic dystrophy type 1 (DM1) in Japanese subjects.

METHODS

For the 32 couples who consented to participate in PGT for DM1, CTG repeats number on the unaffected alleles was analyzed. Based on the allele combination, they were classified into 3 groups by the number of diagnostic allelic pattern; "full informative," "semi informative," and "noninformative." According to the Japan Society of Obstetrics and Gynecology (JSOG) principle, PGT was performed using the direct diagnosis to the 288 embryos from the 17 couples who received the ethical approval from both our institution and JSOG.

RESULTS

In the 32 couples, the frequency of CTG repeats on the unaffected alleles showed bimodal distribution. The "full informative," "semi informative," and "noninformative" couples accounted for 46.9% (15/32 couples), 46.9% (15/32 couples) and 6.2% (2/32 couples), respectively. The transferable embryos accounted for 28.9% (33/114 embryos) in the "full informative" couples, although it was limited to 12.6% (22/174 embryos) in the "semi informative" couples.

CONCLUSION

The loss of unaffected embryos which cannot be diagnosed as transferable was a clinically major problem and implied an increase in oocyte retrieval, especially for "semi informative" couples.

Cardiovascular Precision Medicine in the Genomics Era

Precision medicine strives to delineate disease using multiple data sources-from genomics to digital health metrics-in order to be more precise and accurate in our diagnoses, definitions, and treatments of disease subtypes. By defining disease at a deeper level, we can treat patients based on an understanding of the molecular underpinnings of their presentations, rather than grouping patients into broad categories with one-size-fits-all treatments. In this review, the authors examine how precision medicine, specifically that surrounding genetic testing and genetic therapeutics, has begun to make strides in both common and rare cardiovascular diseases in the clinic and the laboratory, and how these advances are beginning to enable us to more effectively define risk, diagnose disease, and deliver therapeutics for each individual patient.

[Congenital myotonic dystrophy type I in a very premature neonate: ethical concerns]

The congenital form of myotonic dystrophy type I (CDM1) corresponds to a>1500 expansion of an unstable trinucleotide (CTG) repeat. Two prognostic factors predict the risk of death in early infancy: maturity of less than 35 weeks of gestation and neonatal invasive ventilation for more than 30 days.

OBSERVATION

The case of a 29-week-old premature female infant, conceived by in vitro fertilization, is reported. Generalized hypotonia led to the diagnosis of the disease. Ethical concertation about withdrawal or maintenance of intensive care was engaged, taking into account the prolonged ventilation, the degree of prematurity, and the parental wishes for maximum care. The infant was extubated after 2 months. At 17 months, motor development and precursors of language were delayed, and difficulties in feeding had required a gastrostomy.

DISCUSSION

Technical advances in neonatal intensive care now allow CDM1 children to survive prolonged ventilation. The signification of such ventilatory needs on patient outcome, particularly for motor handicaps, speech and language delay, and mental deficiency, remains uncertain. The potential impact of in vitro fertilization on disease expression may also be considered.

CONCLUSION

CDM1 is a severe condition, but variability in clinical manifestations and absence of genotype-phenotype correlation result in problems predicting prognosis at the individual level. Ethical issues about the level of care, notably for tracheostomy and gastrostomy, should be adapted to each case, in partnership with parents.

Myotonic dystrophy: diagnosis, management and new therapies

PURPOSE OF REVIEW

Myotonic dystrophies type 1 and type 2 are progressive multisystem genetic disorders with clinical and genetic features in common. Myotonic dystrophy type 1 is the most prevalent muscular dystrophy in adults and has a wide phenotypic spectrum. The average age of death in myotonic dystrophy type 1 is in the fifth decade. In comparison, myotonic dystrophy type 2 tends to cause a milder phenotype with later onset of symptoms and is less common than myotonic dystrophy type 1. Historically, patients with myotonic dystrophy type 1 have not received the medical and social input they need to maximize their quality and quantity of life. This review describes the improved understanding in the molecular and clinical features of myotonic dystrophy type 1 as well as the screening of clinical complications and their management. We will also discuss new potential genetic treatments.

RECENT FINDINGS

An active approach to screening and management of myotonic dystrophies type 1 and type 2 requires a multidisciplinary medical, rehabilitative and social team. This process will probably improve morbidity and mortality for patients. Genetic treatments have been successfully used in in-vitro and animal models to reverse the physiological, histopathological and transcriptomic features.

SUMMARY

Molecular therapeutics for myotonic dystrophy will probably bridge the translational gap between bench and bedside in the near future. There will still be a requirement for clinical screening of patients with myotonic dystrophy with proactive and systematic management of complications.

Ovarian reserve and PGD treatment outcome in women with myotonic dystrophy

Myotonic dystrophy (DM) is the most common form of muscular dystrophy in adults. There are conflicting reports about its effect on female fertility. This study investigated ovarian reserve and IVF-preimplantation genetic diagnosis (PGD) outcome in women with DM1. A total of 21 women undergoing PGD for DM1 were compared with 21 age- and body mass index-matched women undergoing PGD for other diseases. Ovarian reserve markers, response to stimulation, embryo quality and clinical pregnancy and live birth rates were compared. Day-3 FSH concentration was higher, while anti-Müllerian hormone concentration and antral follicle count were lower in the DM1 group (median, range: 6.9 (1.8-11.3) versus 5.7 (1.5-10.7)IU/l; 0.9 (0.17-5.96) versus 2.68 (0.5-9.1)ng/ml; and 13 (0-63) versus 23 (8-40) follicles, respectively, all P < 0.05). Total FSH dose was higher (5200 versus 2250 IU, P = 0.004), while the numbers of oocytes retrieved (10 versus 16, P < 0.04) and metaphase-II oocytes (9 versus 12, P < 0.03) were lower in the DM1 group. The number of cycles with top-quality embryos and the clinical pregnancy rate were lower in the DM1 group. In conclusion, there is evidence of diminished ovarian reserve and less favourable IVF-PGD outcome in women with DM1. Myotonic Dystrophy (DM) is the most common form of muscular dystrophy in adults. There is evidence of subfertility in males affected with the disease but conflicting reports about the effect of the disease on female fertility. The aim of our study was to investigate ovarian reserve and IVF-PGD results in women with DM. Twenty-one women undergoing preimplantation genetic diagnosis (PGD) treatment for DM were compared to 21 age- and BMI matched women undergoing PGD treatment for other diseases. The two groups were compared for antral follicle count (AFC) and serum anti-Mullerian hormone (AMH) levels (the best known markers of ovarian reserve and fertility potential), ovarian response, embryo quality and pregnancy and live birth rates. AFC and the AMH levels were statistically significant lower in the DM group. Total medication dose needed for ovarian stimulation was higher, the number of oocytes and mature oocytes retrieved, and the number of cycles with top quality embryos were lower in the DM group compared to the controls. In conclusion, there is evidence of diminished ovarian reserve, and less favorable IVF-PGD outcome in women with DM. Therefore, we recommend advising these women about the possibility of early decreasing ovarian function in order to prevent any delay in reproductive planning.

Molecular genetics and genetic testing in myotonic dystrophy type 1

Myotonic dystrophy type 1 (DM1) is the most common adult onset muscular dystrophy, presenting as a multisystemic disorder with extremely variable clinical manifestation, from asymptomatic adults to severely affected neonates. A striking anticipation and parental-gender effect upon transmission are distinguishing genetic features in DM1 pedigrees. It is an autosomal dominant hereditary disease associated with an unstable expansion of CTG repeats in the 3'-UTR of the DMPK gene, with the number of repeats ranging from 50 to several thousand. The number of CTG repeats broadly correlates with both the age-at-onset and overall severity of the disease. Expanded DM1 alleles are characterized by a remarkable expansion-biased and gender-specific germline instability, and tissue-specific, expansion-biased, age-dependent, and individual-specific somatic instability. Mutational dynamics in male and female germline account for observed anticipation and parental-gender effect in DM1 pedigrees, while mutational dynamics in somatic tissues contribute toward the tissue-specificity and progressive nature of the disease. Genetic test is routinely used in diagnostic procedure for DM1 for symptomatic, asymptomatic, and prenatal testing, accompanied with appropriate genetic counseling and, as recommended, without predictive information about the disease course. We review molecular genetics of DM1 with focus on those issues important for genetic testing and counseling.

A case report on 30-week premature twin babies with congenital myotonic dystrophy conceived by in vitro fertilization

Congenital myotonic dystrophy type 1 (DM1) presents severe generalized weakness, hypotonia, and respiratory compromise after delivery with high mortality and poor prognosis. We presented a congenital DM1 of premature twins in the 30th week of gestation. These twins were conceived by in vitro fertilization (IVF). Both babies presented apnea and hypotonia and had characteristic facial appearance. They were diagnosed DM1 by genetic method. They were complicated by chylothorax and expired at 100 and 215 days of age, respectively. Mother was diagnosed DM1 during the evaluation of babies. This is the first report on congenital DM1 which accompanied the chylothorax. More investigation on the association with chylothorax and congenital DM1 is recommended. With a case of severe neonatal hypotonia, congenital DM1 should be differentiated in any gestational age. Finally, since DM1 is a cause of infertility, we should consider DM1 in infertility clinic with detailed history and physical examination.

Preimplantation genetic diagnosis in female and male carriers of reciprocal translocations: clinical outcome until delivery of 312 cycles

Carriers of reciprocal translocations (rcp) are known to be at risk for reproductive difficulties. Preimplantation genetic diagnosis (PGD) is one of the options these carriers have to try in order to fulfil their desire to have a child. In the present study, we retrospectively looked at the results of 11 years (1997-2007) of PGD for rcp in our center to improve the reproductive counseling of these carriers. During this period 312 cycles were performed for 69 male and 73 female carriers. The mean female age was 32.8 years, the mean male age 35.8 years. Most carriers were diagnosed with a translocation because of fertility problems or recurrent miscarriages, and most of them opted for PGD to avoid these problems. In 150 of the 312 cycles, embryo transfer (ET) was feasible and 40 women had a successful singleton or twin pregnancy. This gives a live birth delivery rate of 12.8% per started cycle and of 26.7% per cycle with ET. Owing to the large number of abnormal embryos, PGD cycles for rcp often lead to cancellation of ET, explaining the low success rate when expressed per cycle with oocyte pick-up. Once ET was feasible, the live birth delivery rate was similar to that of PGD in general at our center. PGD is therefore an established option for specific reciprocal translocation carriers.