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

Intergenerational Influence of Gender and the DM1 Phenotype of the Transmitting Parent in Korean Myotonic Dystrophy Type 1

Myotonic dystrophy type 1 (DM1) is the most common autosomal-dominant disorder caused by the CTG repeat expansion of the DMPK, and it has been categorized into three phenotypes: mild, classic, and congenital DM1. Here, we reviewed the intergenerational influence of gender and phenotype of the transmitting parent on the occurrence of Korean DM1. A total of 44 parent–child pairs matched for the gender of the transmitting parent and the affected child and 29 parent–child pairs matched for the gender and DM1 phenotype of the transmitting parent were reviewed. The CTG repeat size of the DMPK in the affected child was found to be significantly greater when transmitted by a female parent to a female child (DM1-FF) (median, 1309 repeats; range, 400–2083) than when transmitted by a male parent to a male child (650; 160–1030; p = 0.038 and 0.048 using the Tukey HSD and the Bonferroni test) or by a male parent to a female child (480; 94–1140; p = 0.003). The difference in the CTG repeat size of the DMPK between the transmitting parent and the affected child was also lower when transmitted from a male parent with classic DM1 (−235; −280 to 0) compared to when it was transmitted from a female parent with mild DM1 (866; 612–905; p = 0.015 and 0.019) or from a female parent with classic DM1 (DM1-FC) (605; 10–1393; p = 0.005). This study highlights that gender and the DM1 phenotype of the transmitting parent had an impact on the CTG repeat size of the DMPK in the affected child, with greater increases being inherited from the DM1-FF or DM1-FC situations in Korean DM1.

Chylothorax as a complication of congenital myotonic dystrophy: A retrospective cohort study

BACKGROUND

The association between congenital myotonic dystrophy (CMD) and chylothorax is poorly recognized.

AIMS

To evaluate the proportion of chylothorax in infants with CMD compared to its prevalence in infants without CMD.

STUDY DESIGN

Single-center, retrospective, cohort study.

SUBJECTS

Infants managed at a neonatal intensive care unit from 2003 to 2019.

OUTCOME MEASURES

CMD was diagnosed using Southern blot for the quantification of CTG repeats in the dystrophia myotonica protein kinase (DMPK) gene. Prenatal and postnatal data of eligible infants with CMD were collected from the patients' medical records. The primary outcome was the proportion of chylothorax.

RESULTS

While the proportion of chylothorax in eligible infants without CMD was 0.25% (27/10714), that in infants with CMD was 50% (5/10; odds ratio (OR), 386.3; 95% confidence interval (CI), 84.4-1850.8; P < 0.001). The variables that were significantly different between infants with CMD with chylothorax and those without chylothorax were as follows: maternal age (33.0 vs. 24.8; P = 0.005), polyhydramnios (5/5 vs 1/5; P = 0.034), number of CTG repeats (1980 vs. 1500; P = 0.038), duration of invasive mechanical ventilation (220 vs. 2, P = 0.009), and duration of hospitalization (217.2 vs 68.0; P = 0.014). The mortality rate of all eligible infants with CMD was 5/10 (50%). No variables were significantly associated with mortality.

CONCLUSIONS

The proportion of chylothorax in infants with CMD was significantly higher than that in infants without CMD. Furthermore, the proportion was higher than that reported in previous studies on congenital chylothorax. This suggests that chylothorax may be frequently experienced in the clinical course of CMD.

A systematic review of monogenic etiologies of nonimmune hydrops fetalis

Hydrops Fetalis (HF), accumulation of fluid in two or more fetal compartments, is life-threatening to the fetus. Genetic etiologies include many chromosomal and monogenic disorders. Despite this, the clinical workup typically evaluates limited genetic targets. To support broader molecular testing of pregnancies with HF, we cataloged the spectrum of monogenic disorders associated with nonimmune hydrops fetalis (NIHF).

We performed a systematic literature review under PROSPERO tag CRD42018099495 of cases reporting NIHF meeting strict phenotypic criteria and well-defined genetic diagnosis. We ranked the evidence per gene based on number of reported cases, phenotype and molecular/biochemical diagnosis.

We identified 131 genes with strong evidence for an association with NIHF and 46 genes with emerging evidence spanning the spectrum of multisystem syndromes, cardiac disorders, hematologic disorders, and metabolic disorders. Several genes previously implicated with NIHF did not have any reported cases in the literature with both fetal hydrops and molecular diagnosis. Many genes with strong evidence for association with NIHF would not be detected using current sequencing panels.

Nonimmune HF has many possible monogenic etiologies, several with treatment implications, but current diagnostic approaches are not exhaustive. Studies are needed to assess if broad sequencing approaches like whole exome sequencing are useful in clinical management of HF.

Clinical study of a patient with congenital myotonic dystrophy reveals chylothorax as neonatal presentation of the disease

Congenital myotonic dystrophy type 1 presents with severe generalized weakness, hypotonia and respiratory involvement after birth with high mortality and poor outcome among survivors. We report on a patient that prenatally showed polyhydramnios and arthrogypotic attitude. Postnatal examination was compatible with the diagnosis of congenital myopathy. A rare finding associated with the patient was chylothorax. Genetic testing confirmed the diagnosis of myotonic dystrophy. Few prenatal and neonatal cases of congenital myotonic dystrophy associated with chylothorax have been reported in the literature. We reviewed all cases reported to date showing congenital myopathic weakness in association with chylothorax to delineate the clinical manifestations that allow an early diagnosis and management of this syndrome. Possible mechanisms to explain the association between myopathy and chylothorax are also discussed.

A premature baby with bilateral pleural effusions, Turner syndrome (monosomy X) and myotonic dystrophy

Respiratory distress in the premature neonate has a variety of causes, some more common than others. Sometimes it may not be apparent that rare underlying conditions may be associated with common clinical presentations. In this case report, we describe an extremely premature neonate presenting with severe respiratory distress who was subsequently diagnosed with both myotonic dystrophy and Turner syndrome (monosomy X; 45, X0). A literature review correlating this neonate’s particular presentation with these diagnoses has been included.

Gonadal failure is associated with visceral adiposity in myotonic dystrophies

BACKGROUND

Hypogonadism occurs in myotonic dystrophies type 1 (MD1) and type 2 (MD2). Sertoli and Leydig cell secretions, including insulin-like peptide-3 (INSL3), anti-Müllerian hormone (AMH) and inhibin B, were evaluated in male patients with MD.

DESIGN

Academic settings. Forty-four male patients with MD [31 MD1, 13 MD2, aged 59 (50-64) years, median (interquartile range)], age-, sex- and BMI-matched non-MD hypogonadal patients (n = 14) and healthy controls (n = 32). Serum FSH, LH, inhibin B, AMH, testosterone (T) and INSL3 were measured; fat and muscle masses were evaluated by DEXA.

RESULTS

Overt primary hypogonadism occurred in 29% of patients with MD1 and 46% of patients with MD2. Considering subclinical forms, the prevalence increased to 69% of MD1 and 100% of MD2. A half of patients with MD experienced symptoms. INSL3 levels were unaffected in most patients with MD. By contrast, AMH and inhibin B were reduced in most patients with MD and unrelated to age. Patients with MD showed increased body and visceral fat. Free T levels were negatively predicted by fat mass, and AMH and FSH levels were negatively correlated with waist/hip ratio and fat mass. AMH, inhibin B and FSH levels positively correlated with muscle strength and muscle mass.

CONCLUSIONS

AMH and inhibin B secretion failures are common in male patients with MD and are more severe than Leydig cell hormones impairment. AMH and inhibin B measurements might provide clinical utility in evaluating fertility in patients with MD. Serum T, AMH and inhibin B productions are negatively influenced by increased fat mass, while AMH and inhibin B might be markers of muscle impairment.

Severe congenital nemaline myopathy with primary pulmonary lymphangiectasia: unusual clinical presentation and review of the literature

Introduction

Nemaline myopathy is a rare genetic muscle disorder defined by the presence of nemaline rods in the muscle fibre sarcoplasm. Congenital nemaline myopathy is the most serious form of the disease’s spectrum.

Case presentation

The affected newborn has no spontaneous movement, fractures at birth and respiratory insufficiency. The present case was a Thai male, floppy at birth with fractures of both humeri and femurs and ventilator-dependent respiration. The patient developed bilateral chylothorax two weeks later and died at the age of 6 weeks. Whole-body postmortem examination with informed consent and genetic analysis of ACTA1 mutation were performed. A skeletal muscle biopsy examined by light and transmission electron microscopy showed the features of nemaline myopathy. ACTA 1 heterozygous missense mutation (c.1127G > C) was identified. Histological examination of both lungs revealed primary pulmonary lymphangiectasia.

Conclusion

To the best of our knowledge, congenital nemaline myopathy with primary pulmonary lymphangiectasia causing bilateral chylothrax has never been previously reported. Considering chylothorax as a poor prognostic index and an unusual clinical presentation of severe congenital NM are proposed.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9710506431489501.