Trichorhinophalangeal syndrome type I

background

Trichorhinophalangeal syndrome type I (TRPS I) is a form of ectodermal dysplasia, one of a group of disorders deriving from prenatal abnormalities of the ectodermal structures, such as hair, teeth, nails, and sweat glands.
Trichorhinophalangeal syndrome type I is an extremely rare inherited multisystem disorder characterized by thin, sparse scalp hair, distinctive facial features, abnormalities of the fingers and toes, and skeletal dysplasia (multiple abnormalities of the "growing ends" of the bones). Characteristic facial features may include a rounded pear-shaped nose, an abnormally small jaw, dental anomalies, and unusually large ears. Individuals with TRPS may be slow to develop communication skills. There are three known types (I, II, and III) of trichorhinophalangeal syndrome.
TRPS I is marked by abnormalities of the bones and mild growth retardation. Bone problems may include cone-shaped bones in the fingers and toes, hip problems, and short stature. These features are typically detected later in childhood. Individuals with TRPS I tend to be of average intelligence.
TRPS I is passed down among family members. It is caused by a mutation or defect in the TRPS1 gene. The TRPS1 gene encodes the TRPS I protein and has been identified as a transcription factor, with two alternative transcripts, and is expressed in the fetal brain and kidney, and in the adult heart, brain, placenta, lung, liver, skeletal muscle, and pancreas.
TRPS I is usually inherited as a dominant trait, meaning that only one copy of the defective gene is needed for the condition to appear. However, it has been suggested that TRPS may be an autosomal recessive trait, meaning that two copies of the defective gene must be inherited for the condition to appear.
TRPS I affects males and females equally. Symptoms range from extremely mild to severe, which may make diagnosis difficult. In addition, the actual incidence of the condition is not known because many cases are not diagnosed.
Various treatments exist to address some of the symptoms associated with TRPS I. These may include surgery for the cone-shaped bone ends in the long bones of individuals with TRPS I, proper dental care, nonsteroidal anti-inflammatory drugs (NSAIDs) for relief from pain and inflammation, physical therapy, and speech-language therapy.

Related Terms

Autosomal dominant, ectodermal dysplasia, inherited genetic disease, trichorhinophalangeal syndrome type I, trichorhinophalangeal syndrome type II, trichorhinophalangeal syndrome type III, TRP syndrome, TRP syndrome I, TRPS I, TRPS1.

types of the disease

There are three types (I, II, and III) of trichorhinophalangeal syndrome.
TRPS I is marked by abnormalities of the bones and mild growth retardation. Bone problems may include cone-shaped bones in the fingers and toes, hip problems, and short stature. These features are typically detected later in childhood. Individuals with TRPS I tend to be of average intelligence.
Trichorhinophalangeal syndrome type II is characterized by a bulbous, pear-shaped nose, elongated upper lip, sparse hair, cone-shaped bone ends, and mild growth retardation, as is observed in TRPS I and III. However, TRPS II can be distinguished from TRPS I by the presence of extra skin. While TRPS I is inherited in an autosomal dominant fashion, most cases of TRPS II occur spontaneously, although there are a few cases that are inherited.
Trichorhinophalangeal syndrome type III shares many common features with TRPS I. However, unlike TRPS I, TRPS III is associated with extremely short fingers and short stature. The mechanisms underlying the genetic transmission of TRPS III have not been determined.