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

Bone Quality in Patients with a Congenital Myopathy: A Scoping Review

BACKGROUND

Congenital myopathies are rare neuromuscular disorders presenting with a wide spectrum of clinical features, including long bone fractures (LBFs) that negatively influence functional prognosis, quality of life and survival. Systematic research on bone quality in these patients is lacking.

OBJECTIVE

This scoping review aims to summarize all evidence on bone quality and to deduce recommendations for bone quality management in congenital myopathies.

METHODS

Five electronic databases (Pubmed, Embase, Cochrane, Web of Science, CINAHL) were searched. All studies on bone quality in congenital myopathies were included. Decreased bone quality was defined as low bone mineral density and/or (fragility) LBFs. Study selection and data extraction were performed by three independent reviewers.

RESULTS

We included 244 single cases (mean: 4.1±7.6 years; median: 0 years) diagnosed with a congenital myopathy from 35 articles. Bone quality was decreased in 93 patients (37%) (mean: 2.6±6.8 years; median: 0 years). Low bone mineral density was reported in 11 patients (4.5%) (mean: 10.9±9.7; median: 11 years). Congenital LBFs were reported in 64 patients (26%). (Fragility) LBFs later at life were described in 24 patients (9.8%) (mean: 14.9±11.0; median: 14 years). Four cases (1.6%) were reported to receive vitamin D and/or calcium supplementation or diphosphonate administration.

CONCLUSION

LBFs are thus frequently reported in congenital myopathies. We therefore recommend optimal bone quality management through bone mineral density assessment, vitamin D and calcium suppletion, and referral to internal medicine or pediatrics for consideration of additional therapies in order to prevent complications of low bone mineral density.

Pediatric Nemaline Myopathy: A Systematic Review Using Individual Patient Data

Nemaline myopathy is a skeletal muscle disease that affects 1 in 50 000 live births. The objective of this study was to develop a narrative synthesis of the findings of a systematic review of the latest case descriptions of patients with NM. A systematic search of MEDLINE, Embase, CINAHL, Web of Science, and Scopus was performed using Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using the keywords pediatric, child, NM, nemaline rod, and rod myopathy. Case studies focused on pediatric NM and published in English between January 1, 2010, and December 31, 2020, in order to represent the most recent findings. Information was collected about the age of first signs, earliest presenting neuromuscular signs and symptoms, systems affected, progression, death, pathologic description, and genetic changes. Of a total of 385 records, 55 case reports or series were reviewed, covering 101 pediatric patients from 23 countries. We review varying presentations in children ranging in severity despite being caused by the same mutation, in addition to current and future clinical considerations relevant to the care of patients with NM. This review synthesizes genetic, histopathologic, and disease presentation findings from pediatric NM case reports. These data strengthen our understanding of the wide spectrum of disease seen in NM. Future studies are needed to identify the underlying molecular mechanism of pathology, to improve diagnostics, and to develop better methods to improve the quality of life for these patients.

Profound Hypotonia and Respiratory Failure due to Suspected Nemaline Myopathy in a Preterm Infant

Congenital myopathies, such as nemaline myopathy, may present with hypotonia and respiratory failure in the neonatal period. Respiratory function can be further compromised in affected infants by the development of chylous effusions. We present the case of a preterm male infant born at 32 ^6/7 weeks' gestation, who was profoundly hypotonic and required intubation at birth. His clinical course progressed from acute to chronic respiratory failure with mechanical ventilation dependence. He developed bilateral chylous pleural effusions during the newborn period. Whole exome sequencing identified an ACTA1 gene mutation leading to the presumed diagnosis of nemaline myopathy. This case highlights the need to include congenital myopathies in the differential for a preterm newborn with hypotonia and respiratory failure.

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.

Congenital pulmonary lymphangiectasia

Congenital pulmonary lymphangiectasia (CPL) is a rare but fatal disease, usually having an onset from the first few hours to days after birth. Inconsistent nomenclatures were used for CPL in the past decades. Patients often present with intractable respiratory failure, hydrops fetalis and even sudden death. The etiologies of CPL remain unclear. Previous hypotheses suggested that CPL might be caused by conditions preventing normal regression of the lymphatics after the 18th-20th week of gestation. Up-to-date biological studies on lymphatic development, lymphatic valve formation and occurrence of hydrops fetalis revealed possible causative relations with mutations of genes of the vascular endothelial growth factor receptor (VEGFR), RAS/MAPK, PI3K/AKT and NF-κB signaling pathways. Lung biopsy with subsequent histological and immunohistochemical studies is a gold standard of CPL diagnosis. Apart from symptomatic and supportive treatments, novel regimens including sirolimus, a mammalian target of rapamycin (mTOR) inhibitor, one of the inhibitors of the pertinent signaling pathways and ethiodized oil lymphatic embolization under ultrasound-guided intranodal lymphangiography have shown encouraging short-term therapeutic effects for lymphatic anomalies. Surgical operations (lobectomy or pneumonectomy) can be the treatment of choice for patients with CPL confined to one lobe or one lung. Patients with CPL usually have a poor prognosis and often die during the neonatal period. Their prognoses are expected to improve with the development of modern therapeutic agents.