A benign congenital myopathy in an inbred Samaritan family

Area of Science:

• Genetics
• Neurology
• Pediatrics

Background:

• Congenital myopathies are a group of inherited muscle disorders presenting at birth or in early infancy.
• Characterized by muscle weakness and hypotonia, their clinical spectrum ranges from mild to severe.
• Novel genetic causes and phenotypes continue to be identified, expanding our understanding of these conditions.

Purpose of the Study:

• To describe a novel form of congenital myopathy observed in an inbred Samaritan family.
• To characterize the clinical presentation, natural history, and muscle biopsy findings.
• To investigate potential genetic causes and determine the mode of inheritance.

Main Methods:

• Clinical evaluation of affected individuals, including motor milestone assessment and physical examination.
• Muscle biopsy with histopathological analysis to examine muscle fiber morphology.
• Exclusion of known genetic mutations associated with common congenital myopathies (SMN, MTM1, myotonic dystrophy genes).

Main Results:

• The study identified a novel myopathy in a mother and her two daughters.
• Patients presented with severe neonatal hypotonia, lethargy, and dysmorphic features, with gradual improvement and achievement of independent walking by 18 months.
• Muscle biopsies revealed central nuclei, disrupted intermyofibrillar network, and moth-eaten/spiral fibers.
• Mutations in SMN, MTM1, and myotonic dystrophy genes were ruled out.

Conclusions:

• The findings suggest a new, benign form of congenital myopathy.
• The probable mode of inheritance is autosomal recessive.
• This condition expands the phenotypic spectrum of congenital myopathies and highlights the importance of investigating consanguineous families.