This syndrome was named after Richard D. Smith, Robert M. Fineman and Gart G. Myers who discovered it around 1980.

This syndrome's external signs would be an unusual facial appearance with their heads being slightly smaller than average, a narrow face (clinically known as dolichocephaly), a large mouth with a drooping lower lip that is held open, protruding upper jaw, widely spaced upper front teeth, an underdeveloped chin, cleft palate and exotropied-slanted eyes with drooping eyelids.

They are restless on occasion, have behavioral problems, seizures and severe delay in language development.

They have cortical atrophy (also known as degeneration) of the brain's outer layer, although it is usually found in older affected people.

This disease only requires one copy of the abnormal X-linked gene to display the syndrome.

They also does a chromosome study and certain other genetic biochemical tests to help figure out any other causes for the mental retardation.

On September 15, 1991 in Sydney, Australia, the Prince of Wales Children's Hospital, reported on two brothers with a distinct facial appearance, severe mental retardation, short stature, cryptorchidism (undescended testicle), asplenia in one (absent spleen), dramatic failure to thrive, early hypotonia, and later hypertonia, all suggestive of the Smith–Fineman–Myers syndrome.

[7] On September 23, 1998 at the Hospital Injury Research and Rehabilitation at the University of São Paulo in Bauru, Brazil report on two boys, monozygotic twins born to normal and non consanguineous parents, presenting with an unusual facial appearance, cortical atrophy, dolichocephaly, short stature, cleft palate, micrognathia, prominent upper central incisors, bilateral Sidney line, minor foot deformities, unstableness in walking, early hypotonia, hyperreflexia, hyperactivity, psychomotor retardation, and severe delay in language development.