Unusual fetal movement in congenital myotonic dystrophy

CpG Methylation, a Parent-of-Origin Effect for Maternal-Biased Transmission of Congenital Myotonic Dystrophy

CTG repeat expansions in DMPK cause myotonic dystrophy (DM1) with a continuum of severity and ages of onset. Congenital DM1 (CDM1), the most severe form, presents distinct clinical features, large expansions, and almost exclusive maternal transmission. The correlation between CDM1 and expansion size is not absolute, suggesting contributions of other factors. We determined CpG methylation flanking the CTG repeat in 79 blood samples from 20 CDM1-affected individuals; 21, 27, and 11 individuals with DM1 but not CDM1 (henceforth non-CDM1) with maternal, paternal, and unknown inheritance; and collections of maternally and paternally derived chorionic villus samples (7 CVSs) and human embryonic stem cells (4 hESCs). All but two CDM1-affected individuals showed high levels of methylation upstream and downstream of the repeat, greater than non-CDM1 individuals (p = 7.04958 × 10⁻¹²). Most non-CDM1 individuals were devoid of methylation, where one in six showed downstream methylation. Only two non-CDM1 individuals showed upstream methylation, and these were maternally derived childhood onset, suggesting a continuum of methylation with age of onset. Only maternally derived hESCs and CVSs showed upstream methylation. In contrast, paternally derived samples (27 blood samples, 3 CVSs, and 2 hESCs) never showed upstream methylation. CTG tract length did not strictly correlate with CDM1 or methylation. Thus, methylation patterns flanking the CTG repeat are stronger indicators of CDM1 than repeat size. Spermatogonia with upstream methylation may not survive due to methylation-induced reduced expression of the adjacent SIX5, thereby protecting DM1-affected fathers from having CDM1-affected children. Thus, DMPK methylation may account for the maternal bias for CDM1 transmission, larger maternal CTG expansions, age of onset, and clinical continuum, and may serve as a diagnostic indicator.

Women's and clinicians perspectives of presentation with reduced fetal movements: a qualitative study

Background

Worldwide maternal perception of fetal movements has been used for many years to evaluate fetal wellbeing. It is intuitively regarded as an expression of fetal well-being as pregnancies in which women consistently report regular fetal movements have very low morbidity and mortality. Conversely, maternal perception of reduced fetal movements is associated with adverse pregnancy outcomes. We sought to gain insight into pregnant women’s and clinicians views and experiences of reduced movements.

Method

We performed qualitative semi-structured interviews with pregnant women who experienced reduced fetal movements in their current pregnancy and health professionals who provide maternity care. Our aim was to develop a better understanding of events, facilitators and barriers to presentation with reduced fetal movements. Data analysis was conducted using framework analysis principles.

Results

Twenty-one women and 10 clinicians were interviewed. The themes that emerged following the final coding were influences of social network, facilitators and barriers to presentation and the desire for normality.

Conclusions

This study aids understanding about why women present with reduced movements and how they reach the decision to attend hospital. This should inform professionals’ views and practice, such that appreciating and addressing women’s concerns may reduce anxiety and make presentation with further reduced movements more likely, which is desirable as this group is at increased risk of adverse outcome. To address problems with information about normal and abnormal fetal movements, high-quality information is needed that is accessible to women and their families.

MANAGEMENT OF REDUCED FETAL MOVEMENTS

Reduced fetal movement (RFM) is commonly defined as any reduction in maternal perception of fetal activity. Perceived fetal activity may be movement of limbs, trunk or head movement, but excludes fetal hiccoughs (as this is involuntary movement). The perception of fetal movement by an expectant mother is the first, and ongoing, non-sonographic indicator of fetal viability. The “normal” pattern of fetal movements varies from pregnancy to pregnancy, and often does not become established until 28 weeks’ gestation. Many babies have particularly active periods of the day, usually corresponding to periods of maternal rest and inactivity (which may in itself reflect increased maternal awareness of fetal movement). A variable percentage of sonographically observed fetal movements are perceived by prospective mothers (commonly 30–40%, although some studies report rates as high as 80%).

Neuromuscular ultrasound

High-resolution ultrasound now is capable of imaging muscle and nerve in fine detail. It is sensitive in detecting chronic myopathies and neurogenic atrophy and may be able to detect subtle changes associated with acute denervation. It is particularly well suited to the study of fasciculations and kinesiology. Recent studies show that ultrasound also is capable of imaging most peripheral nerves,including small branches, and of sensitively measuring the swelling that follows chronic compression. This noninvasive technology holds considerable promise for providing anatomic information to complement other tests of nerve and muscle function.

Chapter 25 Imaging nerve and muscle with ultrasound

Over the last two decades significant advances in ultrasound have made it possible for investigators to image and interpret pathologic changes in muscle and nerve. In addition to being able to assess the pathologic changes in these structures themselves, ultrasound also provides the unique ability to identify anatomic lesions responsible for nerve or muscle injury. They can be correlated with changes in neural structures or affected muscles. Like electrodiagnostic studies, ultrasound is portable and inexpensive, but it is even less invasive, and surprisingly sensitive in detecting a variety of unusual and common causes of neuromuscular dysfunction. Given recent developments in the field, ultrasound shows promise as the technique most suitable for clinical neurophysiologists and neuromuscular clinicians in the growing field of imaging. Such involvement is required to best adopt and exploit the potential of imaging for the research and clinical evaluation of neuromuscular disorders.