General Information

Typical physical characteristics for people with Sotos syndrome

Parents of a child with Sotos syndrome often say after meeting other children with Sotos syndrome, that their child looks more like the other Sotos children than their own siblings! This is because there are a number of physical characteristics that are common amongst those with Sotos.

As mentioned above, typical Sotos characteristics appear to ‘soften’ or become less obvious as the child matures. A rapid rate of growth is especially common during the first 5 years of life and generally children with Sotos syndrome are at the top or off of, the growth charts! This slows down after the age of five and adult height is typically only slightly more than siblings of the same gender. Bone age, while advanced in the first number of years of life, is not advanced in adulthood.

There are likely many people who have Sotos syndrome but have never been diagnosed. It is thought that Sotos syndrome may occur once in every 15,000 or 20,000 births, but many people have never been diagnosed because their symptoms are mild or because they have never been seen by a physician familiar with Sotos and they have therefore been labelled ‘slow’, ‘mentally retarded”, or have been misdiagnosed as having another syndrome or condition.

Developmental delays expected of a person with Sotos syndrome


Hypotonia (low tone or “floppiness”) is a major cause of the motor delays experienced by children with Sotos syndrome. Tone tends to improve as the child matures which leads to an improvement in both gross and fine motor control although coordination problems often persist into adulthood. Low tone of facial muscles may lead to prolonged drooling and mouth breathing but again, this tends to improve by the time the child starts school.


Walking and talking tends to be much later than average. It is not uncommon for a child with Sotos to not walk until about the time of their second birthday. The ability to understand language (receptive language) tends to be more advanced than expressive language (ability to form words and express themselves), which can be very frustrating for the child. Most children develop competent language skills over time and while the tone of their voice may be somewhat ‘flat’, they can be well understood and communicate effectively

While there is a wide range, borderline to average intelligence can be expected. It is not uncommon for the person to have leaning difficulties specifically in language, math and socialization. Intellectual, social, and emotional maturity may evolve on widely different schedules.

Below is a list of characteristic features common in individuals with Sotos syndrome. The list has been reproduced from “Sotos Syndrome: A Handbook for Families”, second edition, by Rebecca Anderson, Bruce Buehler, and Bradley Schaefer.

Features seen in most children (80-100 percent) Features seen in the majority (60-80 percent)
  • Macrocrania (large skull) without megalencephaly (large brain)
  • Dolichocephaly (high, narrow skull)
  • Characteristic structural changes in the brain
  • Prominent forehead, “receding hairline”
  • Hypertelorism (wide space between eyes)
  • High arched palate (roof of mouth is narrow and arched upward)
  • Increased birth length and weight
  • Excessive growth in childhood
  • Disproportionately large hands and feet
  • Low muscle tone
  • Developmental delay
  • Expressive language delay
  • Advanced bone age (above 97th percentile)
  • Premature tooth eruption, soft enamel
  • Poor fine motor control
  • Down-slanting palpebral fissures or “antimongoloid slant” (eye openings are lower in outer corners than by the nose)
  • Prominent, pointed chin
  • I.Q. in the normal range (>70 I.Q.)
  • Learning disabilities
  • Frequent upper respiratory infections
  • Behavioural disturbance (anxiety, depression, phobias, sleep disturbance, tantrums, irritability, stereotypes, inappropriate speech, withdrawal, hyperactivity)
Features seen in the minority (under 50 percent) Occasional or possibly associated features
  • Hyperbilirubinemia (newborn jaundice)
  • Persistent feeding difficulties and / or reflux
  • Dislocated hips or club feet
  • Prolonged drooling
  • Nystagmus, strabismus (eye movement or focusing problems)
  • Autonomic dysfunction (flushing, excessive sweating, poor temperature control)
  • Seizures
  • Constipation, megacolon
  • Scoliosis (curvature of the spine)
  • Abnormal EEG
  • Heart defects
  • Glucose intolerance (pre-diabetes)
  • Thyroid disorders
  • Hemihypertrophy (uneven limb length or body mass)
  • Neoplasms (tumours and cancers)

Excerpted from “Sotos Syndrome: A Handbook for Families”, second edition, by Rebecca Anderson, Bruce Buehler, & Bradley Schaefer, produced by the Munroe-Meyer Institute, copyright University of Nebraska Medical Center, Omaha, NE ISBN 1-889843-59-8, page 17. Used by permission.