Symptomatic heterozygous X-Linked myotubular myopathy female patient with a large deletion at Xq28 and decrease expression of normal allele

Signs and symptoms of carriers of non-DMD X-linked neuromuscular diseases: A scoping review

BACKGROUND

It has been known for long that females carrying pathogenic variants in the DMD gene often report symptoms and/or exhibit signs of the disease. However, a notable knowledge gap exists concerning the signs and symptoms of female carriers of other X-linked neuromuscular diseases (XLNMDs).

OBJECTIVE

This scoping review aims to provide a comprehensive outline of existing literature regarding the signs and symptoms of carriers of non-DMD XLNMDs to raise awareness among both researchers and clinicians.

METHODS

Three electronic databases were used for the literature search (PubMed, Embase, Web of Science). Studies on the signs and symptoms of carriers of non-DMD XLNMDs were included.

RESULTS

We included 44 articles for this review with a total of 354 carriers of non-DMD XLNMDs (mean age 43.9 years, std. deviation 17.4). Muscular signs and symptoms were reported for 125 carriers (X-linked myotubular myopathy (XLMTM): n = 96 (65%); Kennedy's disease (KD): n = 25 (32%); X-linked recessive Charcot-Marie-Tooth disease (CMTXR): n = 2 (15%); Uruguay faciocardiomusculoskeletal syndrome (FCMSU): n = 1 (33%); Barth syndrome (BS): n = 1 (100%)). In terms of ancillary investigations, abnormalities in histopathology and imaging were the most frequent with 44 carriers having abnormalities found by these testing (XLMTM: n = 36 (24%); Emery-Dreifuss muscular dystrophy 1 (EDMD1): n = 4 (5%); KD: n = 4 (5%) / XLMTM: n = 18 (12%); EDMD1: n = 1 (1%); KD: n = 5 (6%); X-linked myopathy with postural muscle atrophy (XMPMA): n = 19 (83%); BS: n = 1 (100%)). A difference between the number of EDMD1 carriers with cardiovascular signs and symptoms (n = 2 (1%)) and the number of carriers with abnormal electrocardiography tests (n = 20 (23%)) was also noted.

CONCLUSION

Carriers of non-DMD XLNMDs exhibit a variety of signs and symptoms that could impact quality of life, making it vital for clinicians to be aware of these patients.

The assessing of clinical relevance of chromosomal microarray analysis in the prenatal diagnosis of fetal growth restriction

OBJECTIVE

Chromosomal variations are known to play a role in the etiology of fetal growth restriction (FGR). Here, we intend to investigate the significance of Chromosomal Microarray Analysis (CMA) in the prenatal diagnosis of definite FGR.

METHOD

182 pregnant women with FGR participated in our study, undergoing CMA to identify chromosomal abnormalities. The cohort was categorized into isolated FGR, FGR with ultrasound soft marker abnormalities, and FGR associated with structural malformations.

RESULTS

The detection rates of PCNVs in FGR with structural anomalies are significantly higher than those in the isolated FGR group and the FGR group with abnormal ultrasound soft markers (19.0% vs. 2.1%, 19% vs. 1.5%; χ²=9.33, p = 0.005). Compared to FGR with a single system malformation, the diagnostic rate of chromosomal variations in FGR with multiple system malformations is markedly increased (60% vs. 6.3%; p = 0.028). Advanced maternal age, early-onset FGR, and severe FGR do not appear to influence the diagnostic rate of chromosomal variations (p > 0.05).

CONCLUSION

Chromosomal variations pose a significant risk in FGR with structural abnormalities, associated with the number of organ systems involved. Notably, advanced maternal age, early-onset FGR, and severe FGR do not affect the diagnostic rate of chromosomal variations in FGR.

Cardiac Transverse Tubules in Physiology and Heart Failure

In mammalian cardiac myocytes, the plasma membrane includes the surface sarcolemma but also a network of membrane invaginations called transverse (t-) tubules. These structures carry the action potential deep into the cell interior, allowing efficient triggering of Ca2+ release and initiation of contraction. Once thought to serve as rather static enablers of excitation-contraction coupling, recent work has provided a newfound appreciation of the plasticity of the t-tubule network's structure and function. Indeed, t-tubules are now understood to support dynamic regulation of the heartbeat across a range of timescales, during all stages of life, in both health and disease. This review article aims to summarize these concepts, with consideration given to emerging t-tubule regulators and their targeting in future therapies.