Three M Syndrome

At a glance

Congenital disorder that includes dwarfism, low birth weight, and dysmorphic craniofacial features (dolichocephaly, prominent forehead [frontal bossing], triangular-shaped face with pointed chin, large ears, and small mouth). Other features include fragile vertebral column, distinctive malformations of the ribs and scapulae, clinodactyly, short fifth finger, and hyperextensibility of joints.

Synonyms

Dolichospondylic Dysplasia; Three M Slender-Boned Nanism (3-MSBN); Le Merrer Syndrome; Gloomy Face Syndrome; 3M Syndrome; Sulky Face Syndrome.

History

The three M refers to the initials of the authors (McKusick, Miller, and Malvaux) who described this syndrome.

Incidence

Extremely rare. Fewer than 100 patients described.

Genetic inheritance

Autosomal recessive trait. The disease is caused by mutations in Cullin 7 (CUL7) gene on chromosome 6p21.1, accounting for 70% of cases, or in the Obscurin-like 1 (OBSL1) gene on chromosome 2q35–36.1 encoding a cytoskeletal adaptor protein. Potentially a third gene involved.

Clinical aspects

The clinical features are low birth weight dwarfism, short stature, triangular-shaped face (hatchet face), prominent lips, prominent trapezia muscles, grooved anterior thorax, horizontal ribs, winging of the scapulae, hypospadias, spina bifida occulta, and delayed closure of the anterior fontanelle. Radiologically, the vertebral bodies are tall, long bones appear slender, and there is evidence of delayed bone maturation.

Precautions before anesthesia

The disease does not affect the respiratory, cardiac, endocrine, or neuromuscular systems nor has any effect on the metabolism of anesthetic drugs.

Anesthetic considerations

Careful assessment of airway anatomy. Careful assessment of pulmonary function in presence of marked deformity. High incidence of spina bifida occulta. Changes in vertebral bodies may cause difficulty if using regional techniques. Difficult laryngoscopy may be expected because of the small mouth opening and shape.

References