Rothmund-Thomson syndrome investigated by two nationwide surveys in Japan.

BACKGROUND: Rothmund-Thomson syndrome (RTS) is an autosomal recessive genetic disorder characterized by poikiloderma of the face, small stature, sparse scalp hair, juvenile cataract, radial aplasia, and predisposition to cancers. Due to the rarity of RTS, the situation of patients with RTS in Japan has not been elucidated. METHODS: In 2010 and 2020, following the results of a primary questionnaire survey, a secondary questionnaire survey on RTS was conducted nationwide to investigate the number of RTS cases and their associated skin lesions, bone lesions, other clinical features, and quality of life in Japan. RESULTS: In 2010 and 2020, 10 and eight patients with RTS were recruited, respectively. Skin lesions such as poikiloderma, erythema, pigmentation, and abnormal scalp hair were observed in almost all cases. Bone lesions were observed in four cases in the 2010 and 2020 surveys, respectively. Two cases had mutations in the RECQL4 gene in the 2020 survey. CONCLUSIONS: Two nationwide surveys have shown the actual situation of patients with RTS in Japan. Cutaneous and bone manifestations are important for the diagnosis of RTS. However, many patients have no RECQL4 mutations. The novel causative gene of RTS should be further elucidated.

Cancer risk among RECQL4 heterozygotes.

Rothmund-Thomson syndrome (RTS) is an autosomal recessive cancer-predisposition disorder characterized by the presence of a wide range of clinical features including poikiloderma, sparse hair, growth deficiency, cataracts, and skeletal abnormalities. Importantly, two-thirds of individuals with RTS have a significant risk of developing osteosarcoma due to the presence of biallelic pathogenic variants in RECQL4, a critical gene involved in DNA repair and replication. It is unknown whether individuals who are heterozygous for a RECQL4 pathogenic variant also have an increased risk of cancer. To address this question, we examined the largest international RTS registry and analyzed 123 RECQL4 heterozygous family members of RTS probands. Overall, the prevalence of cancer among RECQL4 heterozygous family members was 2.4% (3/123). We found that compared to the age-adjusted population estimate of 5.6% from the Surveillance, Epidemiology, and End Results program, the prevalence of cancer was not significantly different in this cohort of RECQL4 heterozygotes (Fisher's exact test, P = 0.2). Given that the biological parents of individuals with RTS are obligate heterozygotes and that siblings have a fifty-percent chance of being asymptomatic heterozygotes, these findings provide valuable information to help guide clinicians in counseling RTS family members regarding the likelihood of developing cancer.

Understanding photodermatoses associated with defective DNA repair: Syndromes with cancer predisposition.

Hereditary photodermatoses are a spectrum of rare photosensitive disorders that are often caused by genetic deficiency or malfunction of various components of the DNA repair pathway. This results clinically in extreme photosensitivity, with many syndromes exhibiting an increased risk of cutaneous malignancies. This review will focus specifically on the syndromes with malignant potential, including xeroderma pigmentosum, Bloom syndrome, and Rothmund-Thomson syndrome. The typical phenotypic findings of each disorder will be examined and contrasted, including noncutaneous identifiers to aid in diagnosis. The management of these patients will also be discussed. At this time, the mainstay of therapy remains strict photoprotection; however, genetic therapies are under investigation.

Osteosarcoma in patients with Rothmund-Thomson syndrome.

BACKGROUND: Rothmund-Thomson syndrome (RTS) is associated with an increased risk of osteosarcoma, but information about affected patients is limited. PROCEDURE: Seven patients with osteosarcoma, treated in the Cooperative Osteosarcoma Study Group-trials, had a diagnosis of RTS. Their patient-, tumor- and treatment-related variables and outcome were reviewed retrospectively. RESULTS: Median age at diagnosis of osteosarcoma was 13 years (range 7-16), five were female, two male. Tumor involved proximal tibia (n = 4), distal tibia (n = 1), distal fibula (n = 1) and proximal ulna (n = 1). Three patients had metastatic disease at diagnosis. All patients received surgery and chemotherapy. Four of seven patients required dose modifications and three of them terminated treatment prematurely. Complete resection of the primary tumor was achieved in all individuals. Two of three affected patients failed to achieve surgical clearance of their primary metastases and died. The third patient relapsed with multiple metastases and died. Two of four patients with localized disease were alive in first complete remission, a third patient in second complete remission after recurrence and a fourth patient died of acute leukemia, while still in first complete remission of osteosarcoma. CONCLUSIONS: Patients with RTS and osteosarcoma may be cured of their cancer with appropriate multimodal therapy. They should be treated like other osteosarcoma patients but preexisting disorders, needs for special support and development of toxicities have to be considered.

Genetic skin diseases predisposing to basal cell carcinoma.

Basal cell carcinoma (BCC) is the commonest cancer in humans. Predisposing factors reflect common genetic variations and environmental influences in most cases. However, an underlying Mendelian disorder should be suspected in a specific subset of patients, namely those with multiple, early onset lesions. Some specific conditions, including Gorlin, Bazex-Dupré-Christol and Rombo syndromes, and Xeroderma Pigmentosum, show BCC as a prominent feature. In addition, BCC may represent a relatively common, although less specific, finding in many other genodermatoses. These include disorders of DNA replication/repair functions (Bloom, Werner, Rothmund-Thomson and Muir-Torre syndromes), genodermatoses affecting the folliculo-sebaceus unit (Brooke-Spiegler, Schöpf-Schulz-Passarge and Cowden syndromes), immune response (cartilage-hair hypoplasia and epidermodysplasia verruciformis) and melanin biosynthesis (oculocutaneous albinism and Hermansky-Pudlak syndrome), and some epidermal nevus syndromes. Further conditions occasionally associated with BCCs exist, but the significance of the association remains to be proven.

RECQL4-deficient cells are hypersensitive to oxidative stress/damage: Insights for osteosarcoma prevalence and heterogeneity in Rothmund-Thomson syndrome.

Rothmund-Thomson syndrome (RTS) is a heterogeneous disease, associated with increased prevalence of osteosarcoma in very young patients with a mutated RECQL4 gene. In this study, we tested the ability of RECQL4 deficient fibroblasts, derived from a RTS patient to recover from hydrogen peroxide (H(2)O(2))-induced oxidative stress/damage. Immunoperoxidase staining for 8-oxo-deoxyguanosine (8-oxo-dG) formation in RTS and normal human fibroblasts were compared to assess DNA damage. We determined DNA synthesis, cell growth, cell cycle distribution, and viability in RTS and normal human fibroblasts before and after H(2)O(2) treatment. H(2)O(2) induces 8-oxo-dG formation in both RTS and normal fibroblasts. In normal human fibroblasts, RECQL4 was predominantly localized to cytoplasm; nuclear translocation and foci formation occurred in response to oxidant stimulation. After recovery from oxidant exposure, viable RTS fibroblasts showed irreversible growth arrest compared to normal fibroblasts. DNA synthesis decreased significantly in treated RTS cells, with concomitant reduction of cells in the S-phase. These results suggest that enhanced oxidant sensitivity in RECQL4 deficient fibroblasts derived from RTS patients could be attributed to abnormal DNA metabolism and proliferation failure. The ramifications of these findings on osteosarcoma prevalence and heterogeneity in RTS are discussed.

Kindler syndrome in native Americans from Panama: report of 26 cases.

OBJECTIVE: To investigate the clinical, genetic, and laboratory features of 26 patients with Kindler syndrome. DESIGN: Case series of patients recruited when they were seen at outpatient consultations in the Department of Dermatology at the Changuinola Hospital in Bocas del Toro, Panama, between May 1986 and December 1990. SETTING: Clinical history, physical examination, and laboratory studies were done at a community hospital in Panama. Twelve of the patients had further studies performed at a children's hospital in Costa Rica. PATIENTS: A total of 26 patients were entered into the study. They were members of the Ngöbe-Buglé tribe and resided in isolated villages in rural Panama. RESULTS: The major findings were skin fragility with blistering (100%), poikiloderma (96%), photosensitivity (92%), severe cutaneous atrophy (89%), hyperkeratosis of the palms and soles (81%), congenital acral blisters (81%), severe periodontal disease (81%), and phimosis (80% of male subjects). In 1 large family with 10 patients, inheritance of Kindler syndrome followed that of an autosomal recessive disease. Karyotypes in 3 patients and 1 unaffected father were normal. Findings from ultrastructural studies showed replication of lamina densa in 10 patients. CONCLUSIONS: To our knowledge, this study represents the largest series to date of patients with Kindler syndrome. The clinical features confirm previously reported cases, and segregation analysis confirms its autosomal recessive inheritance. We also report severe phimosis as a complication, which has not been previously described in this syndrome.

Poikilodermatous subacute cutaneous lupus erythematosus.

BACKGROUND: Subacute cutaneous lupus erythematosus (SCLE) is a distinct subset of lupus erythematosus with unique clinical, immunological and genetic features. Among the unusual variants of SCLE, there is a poikilodermic presentation. However, to date, only 1 case of poikilodermatous SCLE has been reported. OBJECTIVE: Our goal was to summarize the clinical characteristics and course as well as the pathological, laboratory and immunofluorescence findings of 4 patients with poikilodermatous SCLE. METHODS: A retrospective study was conducted including 54 patients diagnosed as having SCLE between 1980 and 2002. RESULTS: Four patients (7.4%) had SCLE. All patients were alive, and none developed severe systemic involvement in up to 36 years (median, 24 years) after the onset of disease. The most noteworthy laboratory finding was the cutaneous deposition of amyloid. CONCLUSION: Poikilodermatous SCLE represents an uncommon variant within the clinicopathological spectrum of SCLE following a favorable course, in spite of extensive cutaneous involvement. Photosensitivity is the pathomechanism explaining, theoretically, the development of both poikiloderma and cutaneous amyloidosis in such cases.