Simpson-Golabi-Behmel syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Simpson-Golabi-Behmel syndrome is a condition that affects many parts of the body and occurs primarily in males. This condition is classified as an overgrowth syndrome, which means that affected infants are considerably larger than normal at birth (macrosomia) and continue to grow and gain weight at an unusual rate. The other signs and symptoms of Simpson-Golabi-Behmel syndrome vary widely. People with mild cases often live into adulthood.

People with Simpson-Golabi-Behmel syndrome have distinctive facial features including widely spaced eyes (ocular hypertelorism), an unusually large mouth (macrostomia), a large tongue (macroglossia) that may have a deep groove or furrow down the middle, a broad nose with an upturned tip, and abnormalities affecting the roof of the mouth (the palate). The facial features are often described as "coarse" in older children and adults with this condition.

Other features of Simpson-Golabi-Behmel syndrome involve the chest and abdomen. Affected infants may be born with one or more extra nipples, an abnormal opening in the muscle covering the abdomen (diastasis recti), a soft out-pouching around the belly-button (an umbilical hernia), or a hole in the diaphragm (a diaphragmatic hernia) that allows the stomach and intestines to move into the chest and crowd the developing heart and lungs.

Simpson-Golabi-Behmel syndrome can also cause heart defects, malformed or abnormally large kidneys, an enlarged liver and spleen (hepatosplenomegaly), and skeletal abnormalities. Additionally, the syndrome can affect the development of the gastrointestinal system, urinary system, and genitalia. Some people with this condition have mild to severe intellectual disability, while others have normal intelligence.

About 10 percent of people with Simpson-Golabi-Behmel syndrome develop cancerous or noncancerous tumors in early childhood. The most common tumors are a rare form of kidney cancer called Wilms tumor and a cancerous tumor called a neuroblastoma that arises from developing nerve cells.

ORPHANET DEFINITION A rare X-linked multiple congenital anomalies syndrome characterized by pre- and postnatal overgrowth, distinctive craniofacial features, variable congenital malformations, organomegaly and an increased tumor risk.

Frequency in the source

From: MedlinePlus Genetics, National Library of Medicine

Point prevalence: <1 / 1 000 000; Worldwide; Class only. Reported case(s): 250.0; Worldwide. This is a published case count, not prevalence.

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.

Abnormal rib morphology · Very frequent (99-80%)

An anomaly of the rib.

Broad foot · Very frequent (99-80%)

A foot for which the measured width is above the 95th centile for age; or, a foot that appears disproportionately wide for its length.

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.

Cryptorchidism · Very frequent (99-80%)

Testis in inguinal canal. That is, absence of one or both testes from the scrotum owing to failure of the testis or testes to descend through the inguinal canal to the scrotum.

Hepatomegaly · Very frequent (99-80%)

Abnormally increased size of the liver.

Hypertelorism · Very frequent (99-80%)

Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes).

Increased circulating IgE concentration · Very frequent (99-80%)

An abnormally increased overall level of immunoglobulin E in blood.

Macrocephaly · Very frequent (99-80%)

Occipitofrontal (head) circumference greater than 97th centile compared to appropriate, age matched, sex-matched normal standards. Alternatively, a apparently increased size of the cranium.

Macroglossia · Very frequent (99-80%)

Increased length and width of the tongue.

Mandibular prognathia · Very frequent (99-80%)

Abnormal prominence of the chin related to increased length of the mandible.

Multicystic kidney dysplasia · Very frequent (99-80%)

Multicystic dysplasia of the kidney is characterized by multiple cysts of varying size in the kidney and the absence of a normal pelvicaliceal system. The condition is associated with ureteral or ureteropelvic atresia, and the affected kidney is nonfunctional.

Postaxial hand polydactyly · Very frequent (99-80%)

Supernumerary digits located at the ulnar side of the hand (that is, on the side with the fifth finger).

Short foot · Very frequent (99-80%)

A measured foot length that is more than 2 SD below the mean for a newborn of 27 - 41 weeks gestation, or foot that is less than the 3rd centile for individuals from birth to 16 years of age (objective). Alternatively, a foot that appears disproportionately short (subjective).

Short toe · Very frequent (99-80%)

A toe that appears disproportionately short compared to the foot.

Other findings in the same source

From: Orphanet

Additional reported features include Splenomegaly (Very frequent (99-80%)); Supernumerary nipple (Very frequent (99-80%)); Tall stature (Very frequent (99-80%)); Ventricular septal defect (Very frequent (99-80%)); Vertebral fusion (Very frequent (99-80%)); Vertebral segmentation defect (Very frequent (99-80%)); Wide mouth (Very frequent (99-80%)); Abnormal cardiovascular system morphology (Frequent (79-30%)); Abnormal helix morphology (Frequent (79-30%)); Abnormality of speech or vocalization (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; Childhood; Infancy; Neonatal

Inheritance in the source

From: MedlinePlus Genetics, National Library of Medicine

X-linked

Frequency and the population described

From: MedlinePlus Genetics, National Library of Medicine

Point prevalence: <1 / 1 000 000; Worldwide; Class only. Reported case(s): 250.0; Worldwide. This is a published case count, not prevalence.

Which doctor should you see?

The suggested department for discussing Simpson-Golabi-Behmel 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 Simpson-Golabi-Behmel 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.