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Denaturing high-performance liquid chromatography (DHPLC) elution chromatograms and sequencing analysis of Crouzon syndrome patients.
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Context 1
... analysis identied heterozygous mutations in all 11 Apert syndrome patients, with either the p.Pro253Arg (c.758 C > G) or p.Ser252Trp (c.755 C > G) mutation (Fig 1, Table 1). Among the patients with Crouzon syndrome, mutations were identied in eight; three with (Fig 2). The p.Trp290Arg mutation was detected in one familial case of Crouzon syndrome in which the parents were rstdegree cousins (patients 14 and 15). ...
Context 2
... is the pathologic condition that results from premature fusion of one or more cranial sutures. These syndromes feature distinctive facial features and variable hand and foot anomalies. Involvement ranges from severe with neonatal death to mild with no clinical manifestations, with a prevalence of 1 in 2100-3000. 1,2 The classical craniosynostosis syndromes are autosomal dominant dis- orders that include Apert (MIM 101200), Crouzon (MIM 123500), Pfeiffer (MIM 101600), Saethre-Chotzen (MIM 101400), Jackson-Weiss (MIM 123150), Beare-Stevenson cutis gyrata (MIM 123790), and Antley-Bixler syndrome (MIM 207410). 1-5 It is well known that craniosynostosis is genetically heterogeneous, and several mutations in fi broblast growth factor receptors ( FGFR ) 1, 2, 3, and TWIST genes have been identi fi ed. Upon ligand binding of fi broblast growth factors (FGFs) to the extracellular domain, the receptors dimerize and, by the activation of the intracellular tyrosine kinase domain, initiates a cascade of signals that regulate multiple cellular activities, cell growth, differentiation, and embry- onic development. 6-10 The molecular defects most frequently occur in FGFR2 (NM_001144916.1), a tyrosine kinase receptor gene, which has been mapped to 10q25.3-26. Mutation analysis of FGFR2 gene detected > 98% for Apert syndrome, around 50% for Crouzon syndrome, and 67% for Pfeiffer syndrome. 11 From a clinical view, two mutations, p.Ser252Trp and p.Pro253Arg, in the immunoglobulin-like extracellular subdomain exon IIIa of the FGFR2 gene account for 98% of Apert syndrome patients, making diagnosis easy and allowing genetic counseling in dif fi cult cases. However, a broad range of mutations throughout the extracellular domain of FGFR2 causes the overlapping of cranial phenotypes of Crouzon and Pfeiffer syndromes and related craniofacial dysostoses. 12,13 Mutations in the FGFR2 gene have been identi fi ed in both Apert and Crouzon syndromes in various ethnic groups, including Japanese, Chinese, Taiwanese, and Southeast Asian patients. 6-10 In the current study, we performed denaturing high-performance liquid chromatography (DHPLC) analysis, followed by sequencing analysis in 100 Anatolian-origin Caucasian Turkish patients with craniosynostosis. We demonstrated the mutations associated with syndromic craniosynostosis patients and discussed the genotype e phenotype correlations of such mutations in comparison with the literature. In this study, all Turkish Anatolian craniosynostosis patients (n 1⁄4 100) were sporadic, except in two patients with Crouzon syndrome in which both the mother and child were affected. Sequence analysis identi fi ed heterozygous mutations in all 11 Apert syndrome patients, with either the p.Pro253Arg (c.758 C > G) or p.Ser252Trp (c.755 C > G) mutation (Fig 1, Table 1). Among the patients with Crouzon syndrome, mutations were identi fi ed in eight; three with heterozygous p.Trp290Arg (c.868 G > C) mutation; one each with heterozygous p.Cys342Tyr (c.1025 G > A), p.Cys278Phe (c.833 G > T), p.Gln289Pro (c.866 A > C); and a novel mutation p.Tyr340Asn (c.1018 T > A) (Fig 2). The p.Trp290Arg mutation was detected in one familial case of Crouzon syndrome in which the parents were fi rst- degree cousins (patients 14 and 15). The other sporadic patients with p.Trp290Arg, p.Cys278Phe, and p.Gln289Pro mutations had a father of advanced age ( > 40 years old). In addition to reported mutations, a novel T to A trans- version at nucleotide 1018 of the FGFR2 gene was detected in exon IIIc. This novel missense mutation leads to trans- version of tyrosine to asparagine at amino acid 340 of the gene. To clarify whether it is a mutation or polymorphism, we analyzed 50 chromosomes of healthy subjects by sequencing (unpublished observation). The p.Tyr340Asn mutation was not found in any of the subjects. Regarding Pfeiffer syndrome patients, we identi fi ed four different mutations d p.Cys342Arg (c.1024 T > C), p.Pro253Arg (c.758 C > G), p.Trp290Cys (c.870 G > C), and p.Ser351Cys (c.1052 C > G) d in fi ve patients (Fig 3). No FGFR2 gene mutation was detected in any of the patients with Saethre-Chotzen syndrome or with nonsyndromic craniosynostosis. The clinical characteristics and FGFR2 mutations of syndromic craniosynostosis patients are presented in Table 1. Identical mutations in the FGFR2 gene have been reported to cause different phenotypes of craniosynostosis, and even different syndromes, whereas a wide range of mutations in the FGFR2 gene produce a variety of overlapping phenotypes that are usually dif fi cult to classify. 16 Until now, 101 FGFR2 gene mutations have been reported to be related to craniosynostosis phenotypes in the Human Gene Mutation Database. The mutations in patients from various ethnic backgrounds demonstrated similar spectrum, with the majority ( > 90%) of patients with Apert syndrome heterozygous for either of the two mutations (p.Ser252Trp and p.Pro253Arg) and a broader spectrum for patients with Crouzon, Pfeiffer, and Saethre-Chotzen syndromes (Table 2). In this study, we found the mutation detection rate to be 73% of the patients. A recent study of FGFRs 1, 2, 3 and TWIST genes in 99 Canadian patients with craniosynostosis revealed a mutation detection rate of 51%. 17 Analysis of exons IIIa and IIIc only of the FGFR2 gene revealed that the mutation detection rate in patients with Apert and Crouzon syndromes from different populations varied from 31% to 100%, as shown in Table 2. We detected mutations in 11 of 12 patients with Apert syndrome (91.6%), eight of 14 patients with Crouzon syndrome (57%), and fi ve of six patients with Pfeiffer syndrome (83%), with an overall detection rate of 24/33 (72.7%) in the Turkish syndromic craniosynostosis population. Additionally, we did not detect any mutation in patients with Saethre-Chotzen syndrome, which is consistent with the reports that the majority of the patients have mutations in the FGFR3 or TWIST genes, which are not analyzed in this study. 2,18 In addition, no FGFR2 gene mutation was detected in Turkish patients with nonsyndromic craniosynostosis. A different subset of mutations seems to be associated with craniosynostosis, without facial features and extremity abnormalities. Apert syndrome has been found to account for about 4.5% of all cases of craniosynostosis, which results almost exclusively from one of two point mutations (p.Ser252Trp or p.Pro253Arg) in FGFR2 . The majority of cases are sporadic, resulting from new mutations. 19 The frequency of the p.Ser252Trp mutation has been noted to be much higher than that of the p.Pro253Arg mutation in French, 20 Canadian, 17 Taiwanese, 10 and Brazilian patients. 21 Consistent with the literature, we found more p.Ser252Trp (n 1⁄4 7) than the p.Pro253Arg (n 1⁄4 4) mutations. Crouzon syndrome is the most common form of craniosynostosis syndrome, for which more than 50 different mutations have been described. We identi fi ed fi ve FGFR2 mutations, including p.Trp290Arg, p.Cys342Tyr, p.Cys278Phe, p.Gln289Pro, and a novel p.Tyr340Asn in 8/14 (57%) of the Crouzon patients. This proportion is much higher than that reported in two previous studies in which FGFR2 mutations were detected in 7/15 and 6/28 Crouzon patients, respectively. 15,22 Pfeiffer syndrome is another severe form of the disease, and approximately 95% of these cases have been attributed to FGFR2 mutations. 23 We identi fi ed mutations in 4/ 5 (80%) of the Pfeiffer patients. This proportion is higher than that reported in two previous studies in which FGFR2 mutations were detected in 9/17 and 3/8 Pfeiffer patients, respectively. 15 The higher percentage of our results can be attributed to the stringency of the clinical diagnosis. From the clinical perspective, further analysis indicated that patients with a p.Ser252Trp mutation more commonly presented with a cleft palate, marker of more severe craniofacial abnormalities, syndactyly, and radiohumeral synostosis. 6,24 In the current study, all patients had syndactyly, except one with p.Ser252Trp mutation (patient 6). Five of the patients with the ...
Citations
... Craniosynostosis syndrome is genetically heterogeneous with identified mutations in fibroblast growth factor receptors (FGFR) 1, 2, and 3, and in TWIST genes. The mutation of FGFR2 is detected in more than 98% for Apert syndrome, 50% for Crouzon syndrome, and 67% for Pfeiffer syndrome (Nur et al., 2014). Reported clinical complications include ventricular expansion, hydrocephalus, expanded subarachnoid space, cerebellar tonsillar herniation, and disturbance of cerebrospinal fluid flow as well as increased intracranial pressure, which can lead to decreased cognitive function and intelligence among patients (Wang et al., 2016). ...
The aim of this study was to compare optic canal parameters of syndromic craniosynostosis patients with those of normal patients to visit the possibility of optic nerve impingement as a cause of visual impairment.
Computed tomography scan images were processed using the Materialise Interactive Medical Image Control System (MIMICS) Research 21.0 software (Materialise NV, Leuven, Belgium). Eleven optic canal parameters were measured: 1) height of optic canal on the cranial side, 2) height of optic canal on the orbital side 3) length of the medial wall of the optic canal, 4) length of the lateral canal wall of the optic canal, 5) diameter of the optic canal at five points (Q1-Q4 and mid canal), and 6) area and perimeter of optic canal. These measurements were obtained for both the right and left optic canals.
The study sample comprised four Crouzon syndrome, five Apert syndrome, and three Pfeiffer syndrome patients. The age of these syndromic craniosynostosis patients ranged from 2 to 63 months. The height of the optic canal on the orbital side (p = 0.041), diameter of the mid canal (p = 0.040), and diameter between the mid-canal and the cranial opening (Q3) (p = 0.079) for syndromic craniosynostosis patients were statistically narrower compared with those of normal patients when a significance level of 0.1 was considered. Scatter plots for the ages of patients versus the above parameters gave three separated clusters that suggested the arresting of optic canal development with age.
The findings from this study demonstrated a narrowing of the optic canal in syndromic craniosynostosis patients, and indicate that optic canal anatomical characteristics may have an association with visual impairment among pediatric syndromic craniosynostosis patients.
... [13,14] The FGFR2 protein serves in the outer membrane of cells which are characterized by an extracellular, transmembrane and an intracellular domain. [15] Such a positioning allows the FGFR2 protein to bind to specific growth factors from outside the cell and transduce the signals which aids the cell to respond to its environment. The FGFR2 protein plays a crucial role in the development of bones before birth (embryonic development). ...
Crouzon syndrome exhibits consideration of phenotypic heterogeneity, within the aetiology of which genetics play a crucial role. The FGFR2 gene mediates extracellular signals into cells and mutations within the FGFR2 gene cause Crouzon syndrome. The review summarizes the genetic phenotype study and genetic evaluation related to Crouzon syndrome (CS) which frequently determines the degree of complexity, guide management, guidance and intervention related to this craniofacial defect. CS is a disorder characterized by early fusion of certain skull bones (craniosynostosis). This prevents normal growth of the skull, which may affect the form of the top and face. Signs and symptoms of Crouzon syndrome may include wide-set, bulging eyes; strabismus (misalignment of the eyes); “beak-shaped” nose; and an underdeveloped upper jawbone. Other features may include dental problems, deafness, and/or harelip and palate. The severity of signs and symptoms can vary among affected people, even within a family. Intelligence is typically normal, but intellectual disability could also be present. Crouzon syndrome is caused by changes (mutations) within the FGFR2 gene and is inherited in an autosomal dominant manner. Treatment may involve surgeries to stop complications, improve function, and aid in healthy psychosocial development. © 2020, Institute of Medico-Legal Publications. All rights reserved.
... The frequency of p.Ser252Trp and p.Pro253Arg pathogenic variants for the FGFR2 in AS has been reported in several populations: in Brazilians 59.25% and 37% (Passos-Bueno et al., 1998), in Canadians 76% and18% (Chun, Teebi, Azimi, Steele, &Ray, 2003), in French 97% and 3% (Lajeunie et al., 1999), in Japanese 83% and 16.66% (Sakai et al., 2001), in Taiwanese 87% and 13.33% (Tsai et al., 1999), in Thais 57% and 42.85% (Shotelersuk et al., 2003), and in Turkish 58% and 33% (Nur et al., 2014). These pathogenic variants in patients with AS of diverse ethnic groups also show a higher frequency in the p.Ser252Trp pathogenic variant, than in p.Pro253Arg pathogenic variant. ...
Background
Craniosynostosis is one of the major genetic disorders affecting 1 in 2,100–2,500 live newborn children. Environmental and genetic factors are involved in the manifestation of this disease. The suggested genetic causes of craniosynostosis are pathogenic variants in FGFR1 , FGFR2 , FGFR3 , and TWIST1 genes.
Methods
In order to describe their major clinical characteristics and the presence of pathogenic variants, a sample of 36 Mexican patients with craniosynostosis diagnosed as: Crouzon (OMIM 123,500), Pfeiffer (OMIM 101,600), Apert (OMIM 101,200), Saethre‐Chotzen (OMIM 101,400), and Muenke (OMIM 602,849) was analyzed.
Results
In addition to craniosynostosis, most of the patients presented hypertelorism, midface hypoplasia, and abnormalities in hands and feet. To detect the pathogenic variants p.Pro252Arg FGFR1 (OMIM 136,350), p.Ser252Trp, p.Pro253Arg FGFR2 (OMIM 176,943), p.Pro250Arg, FGFR3 (OMIM 134,934), and p.Gln119Pro TWIST1 (OMIM 601,622), PCR amplification and restriction enzyme digestion were performed. Four and two patients with Apert presented the pathogenic variants p.Ser252Trp and p.Pro253Arg in FGFR2 , respectively (with a frequency of 11.1% and 5.5%). The p.Pro250Arg pathogenic variant of FGFR3 was found in a patient with Muenke (with a frequency of 2.8%). The above percentages were calculated with the total number of patients.
Conclusion
The contribution of this work is discreet, since only 4 genes were analyzed and sample size is small. However, this strategy could be improved by sequencing the FGFR1 , FGFR2 , FGFR3 , and TWIST1 genes, to determine different pathogenic variants. On the other hand, it would be important to include other genes, such as TCF12 (OMIM 600,480), MSX2 (OMIM 123,101), RAB23 (OMIM 606,144), and EFNB1 (OMIM 300,035), to determine their participation in craniosynostosis in the Mexican population.
... This syndrome affects equally male and female patients 3,5 . Two different types of mutations have been found on the fibroblast growth factor receptor-2 gene (FGFR2, OMIM 176943, NM_001144916.1) in several syndromic craniosynostoses, including AS. Inheritance pattern of AS is autosomal dominant, and over 98% of cases have de novo mutations [2][3][4][5][6][7] . ...
... Craniosynostosis syndrome is genetically heterogeneous with identified mutations in fibroblast growth factor receptors (FGFR) 1, 2, and 3, and in TWIST genes. The mutation of FGFR2 is detected in more than 98% for Apert syndrome, 50% for Crouzon syndrome, and 67% for Pfeiffer syndrome (Nur et al., 2014). Reported clinical complications include ventricular expansion, hydrocephalus, expanded subarachnoid space, cerebellar tonsillar herniation, and disturbance of cerebrospinal fluid flow as well as increased intracranial pressure, which can lead to decreased cognitive function and intelligence among patients (Wang et al., 2016). ...
... 64e74 In the Turkish population, these ratios are 91.6% for Apert syndrome, 57% for Crouzon syndrome, and 83% for Pfeiffer syndrome. 75 As mentioned in the previous section, the FGF receptor signaling cascade involving ERK1/2, p38 MAPK, SAPK/JNK, PKC, and PI3K pathways has been shown to play important roles in regulating MSC differentiation. 38,76 The FGF members exert different effects on osteogenic differentiation of MSCs. ...
Craniosynostosis is one of the pathologic craniofacial disorders and is defined as the premature fusion of one or more cranial (calvarial) sutures. Cranial sutures are fibrous joints consisting of non-ossified mesenchymal cells that play an important role in the development of healthy craniofacial skeletons. Early fusion of these sutures results in incomplete brain development that may lead to complications of several severe medical conditions including seizures, brain damage, mental delay, complex deformities, strabismus, visual and breathing problems. As a congenital disease, craniosynostosis has a heterogeneous origin that can be affected by genetic and epigenetic alterations, teratogens and environmental factors and make the syndrome highly complex. To date, approximately 200 syndromes are correlated to the craniosynostosis. In addition to being part of a syndrome, craniosynostosis can be seen as nonsyndromic formed without any additional anomalies. More than 50 nuclear genes that are relating to the craniosynostosis have been identified. Besides genetic factors, epigenetic factors like microRNAs and mechanical forces also play important roles in suture fusion. Due to craniosynostosis being a multifactorial disorder, evaluating the craniosynostosis syndrome requires and depends on all the information obtained from clinical findings, genetical analysis, epigenetic or environmental factors or gene modulators. In this review, we will focus on embryologic and genetic studies, as well as epigenetic including environmental studies. We will discuss published studies and correlate the findings with unknown aspects of craniofacial disorders.
... This syndrome affects equally male and female patients 3,5 . Two different types of mutations have been found on the fibroblast growth factor receptor-2 gene (FGFR2, OMIM 176943, NM_001144916.1) in several syndromic craniosynostoses, including AS. Inheritance pattern of AS is autosomal dominant, and over 98% of cases have de novo mutations [2][3][4][5][6][7] . ...
Background:
Craniosynostosis is described as the premature fusion of cranial sutures that belongs to a group of alterations which produce an abnormal phenotype.
Case report:
Two unrelated female patients with clinical findings of Apert syndrome-characterized by acrocephaly, prominent frontal region, flat occiput, ocular proptosis, hypertelorism, down-slanted palpebral fissures, midfacial hypoplasia, high-arched or cleft palate, short neck, cardiac anomalies and symmetrical syndactyly of the hands and feet-are present. In both patients, a heterozygous missense mutation (c.755C>G, p.Ser252Trp) in the FGFR2 gene was identified.
Conclusions:
Two cases of Apert syndrome are described. It is important to recognize this uncommon entity through clinical findings, highlight interdisciplinary medical evaluation, and provide timely genetic counseling for the family.
... The etiology of craniosynostosis includes both genetic factors and environmental interference. In recent years, as the application of exome and genome sequencing, mutations of several genes have been identified [20][21][22]. As for the syndromic craniosynostosis, up till now, over 180 syndromes have been identified to be related to the syndromic craniosynostosis, and specific gene mutations or chromosome abnormalities have been checked out over 20% of all cases [13,23,24]. ...
Craniosynostosis, is the premature fusion of one or more cranial sutures which is the second most common cranial facial anomalies. The premature cranial sutures leads to deformity of skull shape and restricts the growth of brain, which might elicit severe neurologic damage. Craniosynostosis exhibit close correlations with a varieties of syndromes. During the past two decades, as the appliance of high throughput DNA sequencing techniques, steady progresses has been made in identifying gene mutations in both syndromic and nonsyndromic cases, which allow researchers to better understanding the genetic roles in the development of cranial vault. As the enrichment of known mutations involved in the pathogenic of premature sutures fusion, multiple signaling pathways have been investigated to dissect the underlying mechanisms beneath the disease. In addition to genetic etiology, environment factors, especially mechanics, have also been proposed to have vital roles during the pathophysiological of craniosynostosis. However, the influence of mechanics factors in the cranial development remains largely unknown. In this review, we present a brief overview of the updated genetic mutations and environmental factors identified in both syndromic and nonsyndromic craniosynostosis. Furthermore, potential molecular signaling pathways and its relations have been described.
... This syndrome affects equally male and female patients 3,5 . Two different types of mutations have been found on the fibroblast growth factor receptor-2 gene (FGFR2, OMIM 176943, NM_001144916.1) in several syndromic craniosynostoses, including AS. Inheritance pattern of AS is autosomal dominant, and over 98% of cases have de novo mutations [2][3][4][5][6][7] . ...
... It has been reported that the p.Ser252Trp mutation is responsible for 71% of cases and the p.Pro253Arg mutation accounts for 26% of cases (2). Similarly, the p.Ser252Trp mutation was found more frequently in Turkish patients in a study conducted by Nur et al. (3). Six new mutations leading to AS have been defined up to the present time in addition to these mutations, which are frequently observed in the FGFR2 gene (4). ...
Apert syndrome is an autosomal dominant craniosynostosis syndrome accompanied by limb anomalies. The fibroblast growth factor receptor 2 (FGFR2) gene is responsible for the disease and two different heterozygous mutations, p.Pro253Arg and p.Ser252Trp, have been defined as responsible in the majority of cases of Apert syndrome. In this case report, two patients with Apert syndrome with two different FGFR2 gene mutations are presented. Case-1, a 4-month-old boy with craniosynostosis and syndactyly was referred to pediatric genetic clinic. The molecular analysis revealed p.Pro253Arg mu- tation in the FGFR2 gene, which confirmed the diagnosis of Apert syndrome. Case-2, a 16-year-old girl with developmental delay, cleft palate, syndactyly, and craniosynostosis, was also diagnosed as having Apert syndrome. A molecular diagnosis identified a p.Ser252Trp heterozygous mutation in the FGFR2 gene. Case-1 underwent surgery for craniosynostosis at age 10 months and he was developmentally normal during the 2 year follow-up period. As a conclusion, early surgical intervention should be considered in cases of Apert syndrome to prevent intellectual disability.
