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Marshall Smith Syndrome

Synonyms of Marshall Smith Syndrome

  • MSS

Disorder Subdivisions

  • No subdivisions found.

General Discussion

Marshall-Smith Syndrome is characterized by unusually quick physical growth and bone development (maturation), usually starting before birth. Other symptoms can include respiratory difficulties, mental retardation, and certain physical characteristics. (Note: Marshall-Smith Syndrome is not to be confused with "Marshall" Syndrome, which is very different from "Marshall-Smith" Syndrome.)


In patients with Marshall-Smith Syndrome growth and bone development (maturation) occur faster than normal. The individual is underweight in relation to his or her height and does not thrive well. Other symptoms include diminished muscle tone (hypotonia), muscle weakness, hernias in the abdomen (umbilical hernias), and/or mental retardation. Slow development of voluntary movements (psychomotor retardation) may also occur.

Breathing (respiratory) difficulties commonly occur in patients with Marshall-Smith Syndrome. High-pitched noisy breathing which sounds similar to the wind blowing (stridor), extension of the neck beyond normal limits (hyperextension), or the tongue obstructing the air passage may occur.

Physical characteristics of Marshall-Smith Syndrome include excessive hair growth (hypertrichosis), a long head with a prominent forehead, prominent eyes, and/or an upturned nose with a low nasal bridge. The white of the eye (sclerae) may appear bluish. The angle of the lower jawbone on each side of the face as it joins in the front to form the chin (mandibular ramus) may be smaller than average. Generally, the bones of the fingertips (distal phalanges) are narrow but the rest of the bones in the fingers (proximal and middle phalanges) are broad.

Infrequently, the leaf-shaped structure in the throat which normally prevents food or liquid from passing into the windpipe (epiglottis) may not develop properly in some patients with Marshall-Smith Syndrome. Absent and/or smaller than normal openings leading from the nasal passages into the post-nasal space (choanal atresia and/or stenosis), an abnormal larynx and/or soft cartilage of the larynx (laryngomalacia), a short breastbone (sternum), or a deep crease between the big toe (hallux) and second toe may occur in some patients.

Occasionally, brain abnormalities such as atrophy (cerebral atrophy), larger than normal convolutions of the cerebral cortex (macrogyria), or an absent corpus collosum may occur. (For more information on absence of the corpus collosum, choose "corpus collosum" as your search term in the Rare Disease Database). Defects in the immune system (immunologic defect) are sometimes present. Although rare, some babies with Marshall-Smith Syndrome are born with a sac containing part of the intestines protruding outside the abdominal wall, with the umbilical cord attached (omphalocele).


The exact cause of Marshall-Smith Syndrome is unknown. There is no evidence that it is genetic.

Affected Populations

Marshall-Smith Syndrome is a rare disorder present at birth affecting males and females in equal numbers. Symptoms of the syndrome are usually present before birth (prenatal onset).

Related Disorders

Weaver Syndrome is similar to Marshall-Smith Syndrome in that growth and bone maturation occur faster than normal. However, patients with Weaver Syndrome have normal to above normal weight in relation to their height whereas patients with Marshall-Smith Syndrome are underweight in relation to their height. There are other differences as well. For example, Marshall-Smith Syndrome patients have different physical characteristics, respiratory difficulties, and other symptoms that patients with Weaver Syndrome do not have. (For more information on Weaver Syndrome, choose "Weaver" as your search term in the Rare Disease Database.)

Gigantism occurs before puberty and is caused by oversecretion of growth hormone. It is characterized by excessive growth during childhood with relatively normal body proportions and sexual development. Height sometimes reaches 7 or 8 feet. Soft tissues are also enlarged. In extreme cases, disease of muscle tissue (myopathy) and abnormalities of nerves distant from the brain and spinal cord (peripheral neuropathy) may occur. Certain hereditary syndromes such as Klinefelter Syndrome, Marfan Syndrome, and some of the lipodystrophies, may include tallness among their symptoms. (For more information choose "gigantism, ""giant," or "peripheral neuropathy" as your search term in the Rare Disease Database.)

Soto's Syndrome is a rare, hereditary disorder characterized by excessive growth (over the 90th percentile) during the first 4 to 5 years of life. Abnormalities of the nervous system, including aggressiveness, irritability, clumsiness, an awkward gait, and mental retardation sometimes also occur. Physical characteristics also include eyes which appear to be abnormally far apart (hypertelorism) and slanted. (For more information, choose "Soto" as your search term in the Rare Disease Database.)

McCune-Albright Syndrome (Osteitis Fibrosa Disseminata) is characterized by an early (precocious) sexual development, a change in bone integrity which produces pain, increasing deformity and disability, and possible changes in skin pigmentation. This syndrome involves the endocrine, muscle and bone systems. Excessive secretion of growth hormone as well as other hormones occurs in some cases. Children with McCune-Albright Syndrome are excessively tall during childhood, but their growth stops early and they usually don't reach normal height during adulthood. (For more information, choose "McCune-Albright" as your search term in the Rare Disease Database.)

Standard Therapies

Treatment of Marshall-Smith Syndrome is symptomatic and supportive. Aggressive treatment of breathing (respiratory) difficulties is necessary. Special education and related services will be necessary during school years.

Investigational Therapies

Information on current clinical trials is posted on the Internet at All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010

For information about clinical trials sponsored by private sources, contact:

Marshall Smith Syndrome Resources



Smith's Recognizable Patterns of Human Malformation, 5th Ed.: Kenneth Lyons Jones, M.D.; W.B. Saunders Co., 1997. Pp. 162-163.

Marshall-Smith Syndrome: Case Report of a Newborn Male and Review of the Literature. D. A. Summers, et al., Clin Dysmorphol. (Jul 1999, 8 (3)). Pp. 207-10.

Anaesthetic Management of a Child with Marshall-Smith Syndrome. G. Dernedde, et al., Can J Anaesth. (Jul 1998, 45 (7)). Pp. 660-63.

Neonatal Death in Marshall-Smith Syndrome. C. Chatel, et al., Genet Couns. (1998,
9 (1)). Pp. 15-18.

Long Survival of a Patient with Marshall-Smith Syndrome without Respiratory Complications. D. Sperli, et al., J Med Genet. (Oct 1993, 30 (10)).
Pp. 877-79.

Marshall-Smith Syndrome: New Radiograhic, Clinical and Pathological Observations. G. F. Eich et al., Radiology, (Oct 1991, 181 (1)). Pp. 183-188.


The information in NORD’s Rare Disease Database is for educational purposes only. It should never be used for diagnostic or treatment purposes. If you have questions regarding a medical condition, always seek the advice of your physician or other qualified health professional. NORD’s reports provide a brief overview of rare diseases. For more specific information, we encourage you to contact your personal physician or the agencies listed as “Resources” on this report.

Report last updated: 2007/08/08 00:00:00 GMT+0

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