What are the signs and symptoms of congenital muscular dystrophy (CMD) with rigid spine?

Updated: Jul 03, 2019
  • Author: Emad R Noor, MBChB; Chief Editor: Amy Kao, MD  more...
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Presentation is at birth or within the first year of life, with variable degrees of proximal weakness and hypotonia.

Most patients eventually walk, but in rare and severe cases, patients never gain independent ambulation. Scapular winging and facial and bulbar weakness are common. Low food intake may be responsible in part for very reduced BMI values (mean 14 kg/m2) in a study of 11 patients with SEPN mutations. [16]

In contrast to Ullrich congenital muscular dystrophy, contractures are not present at birth, but they usually develop at age 3-10 years.

  • The most characteristic pattern is spinal rigidity and scoliosis.

  • Contractures of the face, proximal limbs, and finger extensors may also be present.

Respiratory insufficiency is common and progressive and may be more severe than limb weakness. Forced vital capacity ranged from 18–65% of predicted in 11 patients aged 6–16 years, with 4 aged 2–11 years requiring nighttime noninvasive ventilation. [16] Ventilatory assistance may be needed as early as the first decade of life to treat nocturnal hypoventilation.

Muscle weakness is slowly progressive, and ambulation may be maintained for many years.

The cardiac system is usually normal, but conduction blocks have been reported.

Intelligence and brain MRIs are normal.

In patients with a mutation in selenocysteine insertion sequence-binding protein 2 (SECISBP2, SBP2), there is a multisystem disorder that includes an axial muscular dystrophy similar to SEPN-1 related myopathies. [17]

  • Hypotonia, axial muscle weakness, and spinal rigidity, as well as mild facial, proximal, and respiratory weakness are noted.

  • Other features include azoospermia, cutaneous photosensitivity, impaired T-cell proliferation, increased fat mass with enhanced insulin sensitivity, and hearing loss.

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