Simpson-Golabi-Behmel syndrome

Also known as: DGSX, mental retardation-overgrowth syndrome, SDYS, SGBS, SGBS1, Simpson dysplasia syndrome, Simpson-Golabi-Behmel syndrome type 1, Simpson syndrome

Definition

Genetics Home Reference

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.

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Orphanet

Simpson-Golabi-Behmel syndrome (SGBS, also referred to as SGBS type 1) is 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.

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Symptoms

Medical Term Other Names Description
Wide mouth Macrostomia, Large mouth, Broad mouth, Large oral aperture [more] Distance between the oral commissures more than 2 SD above the mean. Alternatively, an apparently increased width of the oral aperture (subjective).
Hypertelorism Increased distance between eye sockets, Increased distance between eyes, Increased interpupillary distance, Widely spaced eyes, Excessive orbital separation, Widened interpupillary distance, Ocular hypertelorism, Wide-set eyes [more] Interpupillary distance more than 2 SD above the mean (alternatively, the appearance of an increased interpupillary distance or widely spaced eyes).
Neoplasm Oncological abnormality, Neoplasia, Oncology, Tumor, Tumour [more] An organ or organ-system abnormality that consists of uncontrolled autonomous cell-proliferation which can occur in any part of the body as a benign or malignant neoplasm (tumour).
Metatarsus adductus Metatarsus adductovarsus, Metatarsus varus, Forefoot varus, Intoe [more] The metatarsals are deviated medially (tibially), that is, the bones in the front half of the foot bend or turn in toward the body.
Large for gestational age Birthweight > 90th percentile, Macrosomia, neonatal, Macrosomia, Birth weight > 90th percentile, Fetal macrosomia [more] The term large for gestational age applies to babies whose birth weight lies above the 90th percentile for that gestational age.
Enlarged kidney Large kidneys, Renal enlargement, Nephromegaly [more] An abnormal increase in the size of the kidney.
Macroglossia Tongue hypertrophy, Large tongue, Lingual hypertrophy, Increased size of tongue, Lingual hyperplasia, Abnormally large tongue, Hypertrophy of the tongue, Glossal hypertrophy, Hyperplasia of the tongue [more] Increased length and width of the tongue.
Wide nose Increased nasal width, Increased nasal breadth, Increased width of nose, Broad nose, Increased breadth of nose [more] Interalar distance more than two standard deviations above the mean for age, i.e., an apparently increased width of the nasal base and alae.
Renal neoplasm Renal neoplasia, Neoplasia of the kidneys, Kidney cancer, Renal tumors [more] The presence of a neoplasm of the kidney.
Abnormality of cardiovascular system morphology Cardiovascular malformations, Heart defect Any structural anomaly of the heart and great vessels.
Hepatosplenomegaly Enlarged liver and spleen Simultaneous enlargement of the liver and spleen.
Hernia
Congenital diaphragmatic hernia Diaphragmatic hernia The presence of a hernia of the diaphragm present at birth.
Umbilical hernia Protrusion of abdominal contents through a defect in the abdominal wall musculature around the umbilicus. Skin and subcutaneous tissue overlie the defect.
Diastasis recti A separation of the rectus abdominis muscle into right and left halves (which are normally joined at the midline at the linea alba).
Nephroblastoma Wilms tumor The presence of a nephroblastoma, which is a neoplasm of the kidney that primarily affects children.
Overgrowth Generalized overgrowth, Fetal overgrowth, General overgrowth [more] Excessive postnatal growth which may comprise increased weight, increased length, and/or increased head circumference.
Neuroblastoma Neuroblastoma is a solid tumor that originate in neural crest cells of the sympathetic nervous system. Most neuroblastomas originate in the abdomen, and most abdominal neuroblastomas originate in the adrenal gland. Neuroblastomas can also originate in the thorax, usually in the posterior mediastinum.
Hepatomegaly Enlarged liver Abnormally increased size of the liver.
Intellectual disability Nonprogressive intellectual disability, Poor school performance, Mental-retardation, Dull intelligence, Nonprogressive mental retardation, Mental deficiency, Mental retardation, nonspecific, Low intelligence [more] Subnormal intellectual functioning which originates during the developmental period. Intellectual disability, previously referred to as mental retardation, has been defined as an IQ score below 70.

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