Simpson-Golabi-Behmel syndrome type 2

Simpson-Golabi-Behmel syndrome type 2 is an extremely rare and severe condition that presents early in life. It is classified as an overgrowth syndrome with multiple anomalies. This form of the syndrome is recognized for its early-lethal course and a range of structural differences, which may include notable differences in head and facial structure, skin, and limb formation. People with this condition can experience a spectrum of physical findings including macrocephaly, facial dysmorphism such as hypertelorism, distinct ear placement, and variations in the shape of the nose and mouth. There are also skeletal defects, gastrointestinal, and genitourinary anomalies, along with neurological impairments. This overview is based on trusted clinical descriptions provided in the definition.

People with Simpson-Golabi-Behmel syndrome type 2 may show signs that include hydrops fetalis, an unusually large head (macrocephaly), and distinct facial features such as a wide-spaced set of eyes, low-set and backward-angled ears, and a short broad nose with an upward tilt. Other symptoms may include a short neck, extra skin, limb skeletal defects, underdeveloped nails, gastrointestinal and genitourinary anomalies, and low muscle tone. Neurologic impairment, severe intellectual disability, obesity, and increased risk of infections such as pneumonia and sepsis have also been reported.

This condition is linked to genetic changes affecting the OFD1 gene, making it a genetic disorder. The mutation in the OFD1 gene is responsible for the development of this syndrome, which is considered an X-linked recessive condition. The genetic nature of the condition helps explain the range of anomalies seen in affected individuals.

Information about treatment is currently limited for this condition.

Simpson-Golabi-Behmel syndrome type 2 is described as an early-lethal form of an overgrowth syndrome, which indicates that the outlook can be very challenging due to its severe presentation. An early lethal outcome has been noted, but further detailed information about quality of life or long-term outcomes is limited.

Information about research is currently limited for this condition.