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Individual conditions grouped according to the international nosology and classification of genetic skeletal disorders*
Published in Christine M Hall, Amaka C Offiah, Francesca Forzano, Mario Lituania, Michelle Fink, Deborah Krakow, Fetal and Perinatal Skeletal Dysplasias, 2012
Christine M Hall, Amaka C Offiah, Francesca Forzano, Mario Lituania, Michelle Fink, Deborah Krakow
Syndromes with craniosynostosis: Pfeiffer syndrome (p. 397); Apert syndrome (p. 404); Beare-Stevensoncutis gyrata: shows normal hands and feet, natal teeth, cutis gyrata (can be seen at birth), genital anomalies. These syndromes are all due to mutations in the gene FGFR2. Cole-Carpenter syndrome – osteogenesis imperfecta with cranial synostosis; thanatophoric dysplasia (pp. 32-46); craniofrontonasal syndrome: coronal synostosis and frontonasal dysplasia (severe hypertelorism, broad bifid nose, asymmetric frontal bossing), occasionally cleft lip and palate, neck webbing, abnormal clavicles, cutaneous syndactyly and hypoplastic fingers and toes. X-linked dominant; more severe in females; caused by mutations in EFNB1. S aethre-Chotzen syndrome: coronal synostosis (unilateral or bilateral), facial asymmetry, ptosis, characteristic appearance of the ear (small pinna with a prominent crus), syndactyly of digits II and III of the hand. Occasionally: short stature, parietal foramina, radioulnar synostosis, cleft palate, heart malformations. Dominant mutations in TWIST1 are causative. Baller-Gerold syndrome: coronal or multiple suture synostosis, radial aplasia, absent thumb, short and bowed ulna, absent carpal and metacarpal bones. Occasionally hypertelorism, epicanthic folds, prominent nasal bridge, midline capillary haemangi-omas, genitourinary malformations, mental retardation. Caused by mutations of the gene RECQL4.
Rothmund−Thomson Syndrome
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
Vikram K. Mahajan, Dhaarna Wadhwa
Based on clinical and molecular studies, the two clinical forms are identified. The RTS-I has poikiloderma, hypogonadism, juvenile cataract, and no identified gene mutation, while RTS-II having poikiloderma, skeletal abnormalities, and no cataract is due to homozygous or compound heterozygous mutations in the RECQL4 DNA helicase gene mapped to chromosome 8q24.3. The veracity of its pathogenetic role in RTS or whether its two forms are distinct or not remains debatable, as only two-thirds of the RTS patients have homozygous or compound heterozygous mutations for this gene. To date, only one of the 56 different RECQL4 mutations, 39 of which are identified in RTS, is linked mainly to skeletal defects and increased susceptibility for development of osteosarcoma and skin cancer. On the other hand, like poikiloderma, the presence of bilateral cataracts is not a diagnostic feature for RTS-II. Besides, the most common exon 9c.1573delT (p.Cys525AlafsX33) mutation in the RECQL4 gene is also identified in RAPADILINO syndrome and Baller−Gerold syndrome, characterized by radial hypoplasia and craniosynostosis [44–46]. These have several overlapping features (short stature, radial ray abnormalities) but cataract is specific to RTS, joint dislocation and patellar hypoplasia to RAPADILINO, and craniosynostosis to Baller−Gerold syndrome. The development of either osteosarcoma or lymphoma in RAPADILINO patients and NK/T-cell lymphoma in patients with Baller−Gerold syndrome [47,48] is also indicative of predisposition to malignancies in RECQL4-associated syndromes and reflects the spectrum of distinct syndromes with RECQL4 mutations. On the other hand, Clericuzio-type poikiloderma with neutropenia, a clinical sub-entity within the RTS spectrum, lacks RECQL4 mutations and is genetically distinct from RTS [3,49,50]. Clearly, mutation(s) of other as yet unknown or minor gene(s) loci for locus heterogeneity in the other one-third clinically diagnosed RTS patients need to be identified. However, it is possible that the entire phenotypic variations of RTS still remain unexplained as less defined or atypical variants described might be as a result of rare combinations of RECQL4 mutations or novel genomic or epigenetic mechanisms that have remained undetected currently for technical limitations.
Early Prenatal Ultrasound and Molecular Diagnosis of Apert Syndrome: Case Report with Postmortem CT-Scan and Chondral Plate Histology
Published in Fetal and Pediatric Pathology, 2022
Gabriele Tonni, Gianpaolo Grisolia, Maurizia Baldi, MariaPaola Bonasoni, Vladimiro Ginocchi, Liliam Cristine Rolo, Edward Araujo Júnior
Mutations in the gene correlating with Baller-Gerold syndrome and encoding for RECQL4 were normal. A c.758C>Gp. (Pro to Arg substitution) at 252 of the exon 8 of the FGFR2 encoding for Apert syndrome was identified (Figure 3).