Trichorhinophalangeal syndrome is a rare congenital malformation syndrome with chromosome 8 deletion. It is distinguished in types I, II and III.
Common clinical criteria include cone pinned phalanges, pear-shaped deformity of the nose, high philtrum, hairy spinal cord, and premature alopecia. In type I (Sugio-Kajii syndrome), there are also conical epiphyses of the phalanges, possibly also malformations. Type III is associated with pronounced short stature and severe shortening of metacarpal phalanges and/or metatarsal phalanges. In contrast, type II (Langer-Giedion syndrome) is often associated with mental deficits and multiple cartilaginous exostoses. Also, stunted growth, microcephaly, hypotonia and heaviness have been reported. The exostoses occur primarily at the ends of the long bones, causing pain, impairing function and leading to deformity. Exostoses and cone epiphyses develop during the first 5 years of life.
There are significant differences between the three syndrome types in terms of severity and frequency of the disease: type I has mild effects and is relatively common, the serious type II is much rarer, type III is a particularly rare one, and is limited to individual families only. Even within the syndrome types, the expression of the characteristics is very different. Inheritance is autosomal dominant for all types in most cases. Since 2000, it is known that the defective TRPS gene is located at locus 8q24.12. The TRP syndromes are basically incurable.