MARSHALL-SMITH SYNDROME

Marshall-Smith Syndrome (MSS) is a genetic disorder characterized by accelerated skeletal maturation, failure to thrive, respiratory difficulties, dysmorphic facial features, and moderate to severe developmental delay with absent or limited speech and unusual behavior. The exact cause of this disorder is unknown, and no specific chromosomal abnormalities have been identified. This condition is not the same as Marshall syndrome, which is a different genetic syndrome.

Diagnostic testing: Imaging studies showing accelerated bone maturation, or minor brain abnormalities such as hypoplasia of the corpus callosum.

Physical findings: People with MSS may present with:

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  Short stature;

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  Kyphoscoliosis;

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  Nontraumatic fractures;

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  Failure to thrive;

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  Developmental delay or intellectual disability;

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  Respiratory compromise;

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  Unusual facies with wide and prominent forehead (frontal bossing); protruding and widely spaced eyes (proptosis);

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  Depressed nasal bridge;

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  Small upturned nose; and

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  Micrognathia (abnormally small jaws).

ICD-9: 759.89

MSS abnormalities usually begin before birth. Symptoms in children vary in degrees of severity. Mortality is associated with respiratory complications caused by structural problems in the respiratory tract and complications from pneumonia. Children surviving infancy may have developmental delays and intellectual impairment.

There is no cure for MSS. Treatment is symptom specific and supportive. Children with MSS are treated with aggressive management of early respiratory and feeding difficulties.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for Evaluation:

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  Clinical history and examination that describes the diagnostic features of the impairment;

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  Imaging of the skeleton showing accelerated osseous maturation; and

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  Brain imaging showing minor abnormalities such as hypoplasia or absence of the corpus callosum.

Suggested Listings for Evaluation:

REMARKS

Listing-level severity must be documented; may also need to evaluate under the Musculoskeletal, Respiratory, and Mental body systems.

Refer to SSR 98-1p.