Delayed Union of a Jones Fracture in a Patient With Rothmund-Thomson Syndrome: A Case Report and Review of the Literature.

Rothmund-Thomson syndrome is a rare autosomal recessive genodermatosis, characterized by poikiloderma, small stature, juvenile cataracts, sparse hair, skeletal abnormalities, and a predisposition to osteogenic sarcomas and skin cancers. Although numerous skeletal abnormalities have been described in patients with Rothmund-Thomson syndrome, to our knowledge, only 1 study has shown evidence of delayed fracture healing in a patient with Rothmund-Thomson syndrome. We present the case of a 13-year-old female diagnosed with Rothmund-Thomson syndrome who demonstrated delayed union of her fifth metatarsal after a Jones fracture. She was treated conservatively for 6 weeks with non-weightbearing cast immobilization and was then transitioned to a controlled ankle motion walker for an additional 4 weeks. Two months later, however, she continued to experience pain, and, on radiographic examination, the fracture remained unchanged. Therefore, with her guardian's consent, the patient elected to undergo open reduction and internal fixation of the fifth metatarsal fracture. At 8 weeks postoperatively, the patient reported a subsidence of symptoms and had returned to normal activity. With our report, we hope to increase practitioner awareness that delayed bone healing could be a possibility in patients with Rothmund-Thomson syndrome and encourage consideration of routine imaging and supplementation with calcium and vitamin D. Additionally, the present findings suggest that patients with Rothmund-Thomson syndrome could benefit from early surgical intervention, given their poor bone healing capacity and high likelihood of nonunion. Although the association between impaired bone healing and Rothmund-Thomson syndrome is rational, additional studies are needed to determine the prevalence of chronic nonunion in this patient population.

Chronic tibial nonunion in a Rothmund-Thomson syndrome patient.

Rothmund-Thomson syndrome (RTS) is an autosomal recessive disorder caused by biallelic mutations in RECQL4, a helicase involved with chromosomal instability and DNA repair. Patients typically present with a poikilodermatous facial rash, photosensitivity, congenital bony abnormalities, short stature, and have a predilection for osteosarcoma and cutaneous malignancies. We present a 34-year-old male RTS patient, previously diagnosed with osteosarcoma of the right forearm which was successfully treated with resection and chemotherapy, who has had multiple tibial fractures and has suffered from chronic nonunion of the proximal tibias bilaterally for greater than 9 years. The patient subsequently developed generalized lower extremity osteopenia with normal calcium homeostasis and calcitriol levels. As the RTS population continues to reach greater ages we must be mindful of other health concerns that may develop. Bone health is one considerable concern with a large portion of patients having congenital bony abnormalities and many receiving chemotherapy for osteosarcoma. We conclude that screening for bone health and supplementation with calcium and vitamin D may be warranted in RTS patients with a history of fractures and osteosarcoma treatment.

Human diseases deficient in RecQ helicases.

RecQ helicases are conserved from bacteria to man. Mutations in three of the human RecQ family members give rise to genetic disorders characterized by genomic instability and a predisposition to cancer. RecQ helicases are therefore caretakers of the genome, and although they do not directly regulate tumorigenesis, they influence stability and the rate of accumulation of genetic alterations, which in turn, result in tumorigenesis. Maintenance of genome stability by RecQ helicases likely involves their participation in DNA replication, recombination, and repair pathways.

Caretaker tumour suppressor genes that defend genome integrity.

Cancers arise as a result of genetic changes that impact upon cell proliferation through promoting cell division and/or inhibiting cell death. Tumour suppressor (TS) genes are the targets for many of these genetic changes. In general, both alleles of TS genes must be disrupted to observe a phenotypic effect. Broadly speaking, there are two types of TS gene: 'gatekeepers' and 'caretakers'. In contrast to gatekeepers, caretaker genes do not directly regulate proliferation, but act to prevent genomic instability. Thus, mutation of caretaker genes leads to accelerated conversion of a normal cell to a neoplastic cell. Many caretaker genes are required for the maintenance of genome integrity. This review focuses on those caretaker genes that play a role, directly or indirectly, in the repair of DNA strand breaks by the homologous recombination pathway, and that are associated with cancer-prone clinical syndromes, in particular ataxia telangiectasia, hereditary breast cancer, Bloom's syndrome and Werner's syndrome.

Diseases associated with photosensitivity.

Photosensitive disorders may be classified as those entirely caused by solar exposure and the photoaggravated disorders. Those in the former category include polymorphic light eruption, juvenile spring eruption, actinic prurigo, hydroa vacciniforme, solar urticaria, also chronic actinic dermatitis. Genodermatoses whose expression mainly depends on UV or light exposure include the DNA repair deficient disorders, some disorders of cornification, the Smith-Lemli-Opitz syndrome and porphyria. Examples of photoaggravated diseases include lupus erythematosus, erythema multiforme, atopic eczema, psoriasis, viral exanthemata, pemphigus, dermatitis herpetiformis and rosacea. Drugs and chemicals may interact with UV to induce photosensitivity. In many of these diseases the action spectrum is known or may be determined by phototesting. Recognition of the reaction patterns associated with the photodermatoses greatly assists clinical classification of the photodermatoses.

Linking DNA damage and neurodegeneration.

Many human pathological conditions with genetic defects in DNA damage responses are also characterized by neurological deficits. These neurological deficits can manifest themselves during many stages of development, suggesting an important role for DNA repair or processing during the development and maintenance of the nervous system. Although the molecular neuropathology associated with such deficits is largely unknown, many of the responsible gene defects have been identified. The current rapid progress in elucidation of molecular details following gene identification should provide further insight into the importance of DNA processing in nervous system function.

Rothmund-Thomson syndrome.

Rothmund-Thomson syndrome is a rare inherited disorder characterized by poikilodermatous skin changes that appear in infancy. The inheritance is autosomal recessive. Patients exhibit variable features including skeletal abnormalities, juvenile cataracts, and a higher-than-expected incidence of malignancy. This article describes aspects of the inheritance, the incidence of characteristic features, and the malignant potential of Rothmund-Thomson syndrome. Insight into its origin is provided through a review of the clinical signs and symptoms, the in vitro studies of endocrine function, and the reported DNA repair abnormalities.