Trichorhinophalangeal syndrome type 2

Trichorhinophalangeal syndrome type 2 (TRPS2), also known as Langer-Giedion syndrome, is a rare genetic disorder caused by deletions on chromosome 8q23-q24 that encompass both the TRPS1 and EXT1 genes. Because it results from the loss of contiguous genes, it is classified as a contiguous gene deletion syndrome. The condition affects multiple body systems, including the skeletal system, skin, hair, and craniofacial structures. Key clinical features include sparse, thin scalp hair; a bulbous (pear-shaped) nose; a long flat philtrum; a thin upper lip; cone-shaped epiphyses of the phalanges (finger bones); short stature; and multiple cartilaginous exostoses (bony growths near the growth plates of bones). Patients may also present with loose, redundant skin in infancy, mild to moderate intellectual disability, and microcephaly. The exostoses, which arise due to loss of the EXT1 gene, distinguish TRPS2 from trichorhinophalangeal syndrome type 1, which lacks these bony outgrowths. Joint laxity and recurrent upper respiratory infections have also been reported in some individuals. There is currently no cure for TRPS2, and management is symptomatic and supportive. Orthopedic surveillance is important for monitoring and managing exostoses, which may require surgical removal if they cause pain, nerve compression, or restricted movement. Growth hormone therapy may be considered for short stature in some cases, though evidence for its efficacy in this specific syndrome is limited. Regular developmental assessments and educational support are recommended for children with intellectual disability. A multidisciplinary team including geneticists, orthopedic surgeons, dermatologists, and developmental specialists is typically involved in long-term care.

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