9401

RECQL4

RECQ4;RecQ protein-like 4;RECQL4;RecQ protein-like 4

ATP-dependent DNA helicase Q4|DNA helicase, RecQ-like type 4|DNA helicase, RecQ-like, type 4

8q24.3

protein-coding

BTI - GeneReviews#. Baller-Gerold syndrome (BGS) is characterized by coronal craniosynostosis, manifest as abnormal shape of the skull (brachycephaly) with ocular proptosis and bulging forehead; radial ray defect, manifest as oligodactyly (reduction in number of digits), aplasia or hypoplasia of the thumb, and/or aplasia or hypoplasia of the radius; growth retardation and poikiloderma. Findings in individuals with BGS overlap with those of Rothmund-Thomson syndrome (RTS) and RAPADILINO syndrome, also caused by mutations in RECQL4. RTS is characterized bypoikiloderma; sparse hair, eyelashes, and/or eyebrows/lashes; small stature; skeletal and dental abnormalities; cataracts; and an increased risk for cancer, especially osteosarcoma. RAPADILINO syndrome is an acronym for RAdial ray defect; PAtellae hypoplasia or aplasia and cleft or highly arched PAlate; DIarrhea and DIslocated joints; LIttle size and LImb malformation; NOse slender and NOrmal intelligence. The diagnosis of BGS is based on clinical findings. RECQL4 is the only gene currently known to be associated with BGS. Sequence analysis of the exons and the short introns of RECQL4 has detected mutations in 100% of the limited number of persons with BGS tested to date. Treatment of manifestations: Surgery before age six months to repair bilateral craniosynostosis; pollicization of the index finger as needed to create a functional grasp. Surveillance: For persons with deleterious RECQL4 mutations that correlate with an increased risk for osteosarcoma, attention to clinical findings such as bone pain, limp, and fracture. Agents/circumstances to avoid: Sun exposure because of risk for skin cancer. Baller-Gerold syndrome is inherited in an autosomal recessive manner. The parents of an affected child are obligate heterozygotes and therefore carry one mutant allele. Heterozygotes (carriers) are asymptomatic. At conception, each sib of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Carrier testing for at-risk family members and prenatal diagnosis for pregnancies at increased risk are possible if both disease-causing alleles in the family have been identified.#CI- Copyright (c) 1993-2013, University of Washington, Seattle. ALL rights reserved.#FED - Pagon, Roberta A#ED- Pagon RA#FED - Adam, Margaret P#ED- Adam MP#FED - Bird, Thomas D#ED- Bird TD#FED - Dolan, Cynthia R#ED- Dolan CR#FED - Fong, Chin-To#ED- Fong CT#FED - Stephens, Karen#ED- Stephens K#FAU - Van Maldergem, Lionel

BACKGROUND: Human osteosarcoma is the most common pediatric bone tumor. There islimited understanding of the molecular mechanisms underlying osteosarcoma oncogenesis, and a lack of good diagnostic as well as prognostic clinical markers for this disease. Recent discoveries have highlighted a potential role of a number of genes including: RECQL4, DOCK5, SPP1, RUNX2, RB1, CDKN1A, P53, IBSP, LSAMP, MYC, TNFRSF1B, BMP2, HISTH2BE, FOS, CCNB1, and CDC5L. METHODS: Our objective was to assess relative expression levels of these 16 genes as potential biomarkers of osteosarcoma oncogenesis and chemotherapy response in human tumors. We performed quantitative expression analysis in a panel of 22 human osteosarcoma tumors with differential response to chemotherapy, and 5 normal human osteoblasts. RESULTS: RECQL4, SPP1, RUNX2, and IBSP were significantly overexpressed, and DOCK5, CDKN1A, RB1, P53, and LSAMP showed significant loss ofexpression relative to normal osteoblasts. In addition to being overexpressed inosteosarcoma tumor samples relative to normal osteoblasts, RUNX2 was the only gene of the 16 to show significant overexpression in tumors that had a poor response to chemotherapy relative to good responders. CONCLUSION: These data underscore the loss of tumor suppressive pathways and activation of specific oncogenic mechanisms associated with osteosarcoma oncogenesis, while drawing attention to the role of RUNX2 expression as a potential biomarker of chemotherapy failure in osteosarcoma.