Rothmund-Thomson Syndrome (RTS) is a rare genetic disorder that can affect people of all races and nationalities. Symptoms often first appear during infancy, usually between three and six months of age, in the form of a skin rash on the cheeks. Patients can have just a few or several features of the syndrome. Download the RTS Informational Brochure.
To learn more about Rothmund-Thomson Syndrome please watch the following video from Dr. Lisa Wang.
RTS is characterized by the following clinical features
Diagnosis of RTS is primarily made through evaluation of clinical features. In general, having the classic rash (poikiloderma) is the main finding for making the diagnosis of RTS. A skin biopsy may also be helpful in showing changes that are consistent with poikiloderma. Patients may have an "atypical" rash that is not quite classic for RTS, but if they have at least two other of the clinical features associated with RTS, then they are considered to have "Probable RTS." In most cases of RTS, the clinical diagnosis can be confirmed by molecular testing of the RECQL4 gene.
RECQL4 is a gene located on chromosome 8. Genes are packages of DNA, or genetic material that help in the formation of proteins which carry out specific functions in the body. RECQL4 is the only gene that is currently known to be associated with RTS. Patients with mutations, or changes, in both copies of their RECQL4 genes can develop RTS. However, only about two-thirds of patients with clinical diagnosis of RTS will have mutations found in their RECQL4 genes. Therefore, there are likely other genes that can also cause RTS.
DNA sequence analysis and mutation testing of the RECQL4 gene are available through the Baylor College of Medicine Medical Genetics Laboratory. Presence of mutations in RECQL4 can confirm a diagnosis of RTS; however, absence of mutations in RECQL4 does not necessarily mean that the patient does not have RTS, since one-third of patients clinically diagnosed with RTS do not have mutations in this gene. Researchers at Texas Children's Cancer Center have shown that presence of RECQL4 mutations is associated with increased risk for developing osteosarcoma. They are continuing to study the function of the RECQL4 protein to try to understand why lack of this protein leads to the findings seen in RTS.
Since RTS is usually inherited in an autosomal recessive pattern, affected individuals inherit one abnormal (mutated) gene from each parent. If an individual only has a mutation in one gene, then he/she is a carrier (e.g., parents of RTS patients are carriers). Therefore, at conception there is a 25% chance of the offspring of two carriers to be affected with the disease, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected ("normal" RECQL4 genes).
RTS is a rare disorder, and the exact number of cases worldwide is not known. There have been a few hundred cases of RTS reported in the medical literature. RTS is not specific to any once race or nationality. However, because it is a recessive disorder, consanguineous (related by blood) families have an increased risk of disease.
Most parents of an individual affected with RTS wonder if their child will ever be able to lead a normal life. Ongoing research studies conducted at Baylor College of Medicine and Texas Children's Hospital have found that RTS patients can lead very fulfilling lives. Patients appear to have normal life spans (in the absence of cancer), and several have gone on to have families of their own. An RTS support group has been established for patients and their family members and is currently very active and growing.