Sotos syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Sotos syndrome is a disorder characterized by a distinctive facial appearance, overgrowth in childhood, and learning disabilities or delayed development of mental and movement abilities. Characteristic facial features include a long, narrow face; a high forehead; flushed (reddened) cheeks; and a small, pointed chin. In addition, the outside corners of the eyes may point downward (down-slanting palpebral fissures). This facial appearance is most notable in early childhood. Affected infants and children tend to grow quickly; they are significantly taller than their siblings and peers and have an unusually large head. However, adult height is usually in the normal range.

People with Sotos syndrome often have intellectual disability, and most also have neurodevelopmental disorders. Conditions that commonly occur in people with Sotos syndrome include autism spectrum disorder, attention-deficit/hyperactivity disorder (ADHD), phobias, obsessions and compulsions, tantrums, and impulsive behaviors. Problems with speech and language are also common. Affected individuals often have a stutter, a monotone voice, and problems with sound production. Additionally, weak muscle tone (hypotonia) may delay other aspects of early development, particularly motor skills such as sitting and crawling.

Other signs and symptoms of Sotos syndrome can include an abnormal side-to-side curvature of the spine (scoliosis), seizures, heart or kidney defects, hearing loss, and problems with vision. Some infants with this disorder experience yellowing of the skin and whites of the eyes (jaundice) and poor feeding.

A small percentage of people with Sotos syndrome have developed cancer, most often in childhood, but no single form of cancer occurs most frequently with this condition. It remains uncertain whether Sotos syndrome increases the risk of specific types of cancer. If people with this disorder have an increased cancer risk, it is only slightly greater than that of the general population.

ORPHANET DEFINITION A rare genetic overgrowth syndrome characterized by a typical facial appearance, overgrowth with macrocephaly and variable intellectual impairment.

Inheritance

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Prevalence at birth: 1-9 / 1 000 000; Europe; Value and class. Point prevalence: 1-9 / 1 000 000; Europe; Class only.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Coarse facial features · Very frequent (99-80%)

Absence of fine and sharp appearance of brows, nose, lips, mouth, and chin, usually because of rounded and heavy features or thickened skin with or without thickening of subcutaneous and bony tissues.

Increased arm span · Very frequent (99-80%)

Increased length of the arm span (length from one end of an individual's arms measured at the fingertips to the other when raised parallel to the ground at shoulder height at a one-hundred eighty degree angle).

Tall stature · Very frequent (99-80%)

A height above that which is expected according to age and gender norms.

Accelerated skeletal maturation · Frequent (79-30%)

An abnormally increased rate of skeletal maturation. Accelerated skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body.

Astigmatism · Frequent (79-30%)

A type of refraction error associated with abnormal curvatures on the anterior and/or posterior surface of the cornea.

Atypical behavior · Frequent (79-30%)

Atypical behavior is an abnormality in a person's actions that can be controlled or modulated by the will of the individual. While abnormal behaviors can be difficult to control, they are distinct from other abnormal actions that cannot be affected by the individual's will.

Brain imaging abnormality · Frequent (79-30%)

An anomaly of metabolism or structure of the brain identified by imaging.

Chronic otitis media · Frequent (79-30%)

Chronic otitis media refers to fluid, swelling, or infection of the middle ear that does not heal and may cause permanent damage to the ear.

Constipation · Frequent (79-30%)

Infrequent or difficult evacuation of feces.

Dolichocephaly · Frequent (79-30%)

An abnormality of skull shape characterized by a increased anterior-posterior diameter, i.e., an increased antero-posterior dimension of the skull. Cephalic index less than 76%. Alternatively, an apparently increased antero-posterior length of the head compared to width. Often due to premature closure of the sagittal suture.

Downslanted palpebral fissures · Frequent (79-30%)

The palpebral fissure inclination is more than two standard deviations below the mean.

Feeding difficulties · Frequent (79-30%)

Impaired ability to eat related to problems gathering food and getting ready to suck, chew, or swallow it.

Flushing · Frequent (79-30%)

Recurrent episodes of redness of the skin together with a sensation of warmth or burning of the affected areas of skin.

Global developmental delay · Frequent (79-30%)

A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.

Other findings in the same source

From: Orphanet

Additional reported features include Hearing impairment (Frequent (79-30%)); Hypotonia (Frequent (79-30%)); Increased head circumference (Frequent (79-30%)); Intellectual disability, mild (Frequent (79-30%)); Joint hypermobility (Frequent (79-30%)); Long face (Frequent (79-30%)); Narrow face (Frequent (79-30%)); Prolonged neonatal jaundice (Frequent (79-30%)); Prominent forehead (Frequent (79-30%)); Scoliosis (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: MedlinePlus Genetics, National Library of Medicine

Antenatal; Neonatal

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

Autosomal dominant

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Prevalence at birth: 1-9 / 1 000 000; Europe; Value and class. Point prevalence: 1-9 / 1 000 000; Europe; Class only.

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Sotos syndrome is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Sotos syndrome. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.