Expression of Indian Hedgehog, BMP-4 and Noggin in Craniosynostosis Induced by Fetal Constraint

Indian Hedgehog (Ihh), bone morphogenetic protein (BMP), and its antagonist Noggin play an important regulatory role in bone formation. We used an animal model to study the role of these molecules in craniosynostosis induced by fetal constraint. C57Bl/6 mice underwent cervical cerclage on the 18th day of gestation, and their pups were harvested 48 and 72 hours beyond the normal gestational period. Constrained and control calvariae were examined for expression of BMP-4, Noggin, Histone H4C, Ihh, Sonic Hedgehog (Shh), and Patched 1 (Ptch1), one of the Hh transcriptional target molecules/Hh receptors. Constraint-induced suture fusion was associated with decreased expression of Ihh and Noggin, whereas BMP-4 was expressed in both control and constrained sutures. Ptch1 colocalized with Ihh-positive osteogenic cells at the osteogenic fronts, but not with Shh transcripts, suggesting that Ihh, but not Shh, regulates Ptch1 expression in cranial suture development. Histone H4C was preferentially expressed in Ihh-positive cells, indicating that Ihh may regulate osteogenic cell proliferation at the osteogenic fronts. These results suggest a role for Ihh and Noggin signaling in constraint-induced craniosynostosis.

Sudden infant death in a patient with FGFR3 P250R mutation

P250R mutation in the FGFR3 gene also known as Muenke syndrome is associated with coronal craniosynostosis, sensorineural deafness, craniofacial, and digital abnormalities. We report a family with this mutation associated with sudden death in an affected newborn, most probably due to upper airway obstruction.

Obesity, hypothyroidism, craniosynostosis, cardiac hypertrophy, colitis, and developmental delay: A novel syndrome

We describe in two brothers an apparently novel syndrome comprising obesity, congenital hypothyroidism, neonatal colitis, cardiac biventricular hypertrophy, craniosynostosis, and developmental delay. The first brother presented with neonatal colitis and congenital hypothyroidism and died at age 5 weeks of fulminant colitis. The second brother presented neonatally with the same condition, but survived and subsequently developed severe obesity, sagittal and coronal synostosis, and developmental delay. Both pregnancies had been complicated by hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome). Exhaustive genetic and metabolic investigations have failed to provide a unifying pathogenesis. This unique combination of manifestations appears to represent a new syndrome with probable autosomal recessive or X-linked recessive inheritance.

Quantitative and qualitative assessment of morphology in sagittal synostosis: mid-sagittal vector analysis

Consensus remains lacking regarding the optimal surgical treatment modality for sagittal synostosis. There is, however, wide agreement that objective analytical methods are required to demonstrate the characteristic morphology of the condition and to substantiate the benefits of specified surgical techniques. Simple calculated anthropomorphic indices, such as the cranial index, are commonly used but fail to provide satisfactory representation of morphology, which is far more complex than can be represented by its simple length-width ratio. Techniques to provide more comprehensive, yet practical, assessment of morphology are needed for analytic purposes. Herein, we introduce vector analysis as an objective, computed tomography (CT)-based morphometric technique for assessment of cranial morphology; this work represents the first application of the technique mid-sagittal vector analysis (MSVA). MSVA is a single plane application that was devised to address dysmorphology in sagittal synostosis. It was our hypothesis that MSVA would quantitatively and qualitatively depict preoperative morphology and postoperative correction in specific regions. Sixteen patients undergoing cranial reshaping surgery for sagittal synostosis were included in the study. All patients underwent routine preoperative and 1 year postoperative CT scans, from which the MSVA was derived. MSVA is a radial vector analysis in which distances to the cranial surface are measured from a single reference point origin in the sagittal plane. Preoperative morphology, characterized by respective vectors, was analyzed in three regions: the frontal, vertex, and occipital regions. Comparison with postoperative paired data was conducted for each patient. The analysis of postoperative change demonstrated (1) decrease in prominence in the frontal and occipital regions, (2) increase in height and forward translation of the vertex, and (3) ability to distinguish and qualify frontal versus occipital bossing and correction thereof. We conclude that the longitudinal differences associated with scaphocephaly are well characterized and differentiated by MSVA. Quantitative and qualitative assessment identifies three relevant regions affected by the condition and its treatment: the frontal, vertex, and occipital regions. The transverse dimension is not addressed in this single plane analysis; a more comprehensive application will require additional planes of analysis and the development of a normative database.

Craniofacial anomalies, humero-radial synostosis, rhizomelic limb shortness: Previously unrecognized autosomal recessive syndrome

Humero-radial synostosis (HRS) is a rare skeletal anomaly that might be seen in some craniosynostosis syndromes, notably Antley-Bixler syndrome, and in other disorders in association with skeletal anomalies. Here we report on two daughters of first cousin Saudi parents with syndromic HRS. Both patients had distinctive craniofacial features including cranium bifidum occultum, hypertelorism, epicanthus inversus, capillary hemangiomata, and malformed ears. Musculoskeletal examination revealed rhizomelic shortness with normal hands and feet. Skeletal survey showed bilateral HRS with no evidence of craniosynostosis. The craniofacial manifestations in these two patients do not match any of the syndromes known to be associated with HRS. We consider that the constellation is unique and apparently represents a previously unrecognized syndrome.

Attenuation of signaling pathways stimulated by pathologically activated FGF-receptor 2 mutants prevents craniosynostosis

Craniosynostosis, the fusion of one or more of the sutures of the skull vault before the brain completes its growth, is a common (1 in 2,500 births) craniofacial abnormality, approximately 20% of which occurrences are caused by gain-of-function mutations in FGF receptors (FGFRs). We describe a genetic and pharmacological approach for the treatment of a murine model system of Crouzon-like craniosynostosis induced by a dominant mutation in Fgfr2c. Using genetically modified mice, we demonstrate that premature fusion of sutures mediated by Crouzon-like activated Fgfr2c mutant is prevented by attenuation of signaling pathways by selective uncoupling between the docking protein Frs2alpha and activated Fgfr2c, resulting in normal skull development. We also demonstrate that attenuation of Fgfr signaling in a calvaria organ culture with an Fgfr inhibitor prevents premature fusion of sutures without adversely affecting calvaria development. These experiments show that attenuation of FGFR signaling by pharmacological intervention could be applied for the treatment of craniosynostosis or other severe bone disorders caused by mutations in FGFRs that currently have no treatment.

Aesthetic Results of Fronto-Orbital Correction in Trigonocephaly

The aesthetic results of craniofacial surgery for trigonocephaly were evaluated by a panel assessment using a scoring system based on deformities typical for this type of craniosynostosis. In this retrospective study pre-and postoperative photographs of 45 patients were scored for items typical for trigonocephaly: shape of the forehead, hypotelorism, and temporal depression. Each item was quantified as normal or absent (0 points), a mild deformity (1 point) or a severe deformity (2 points). Preoperatively, the most obvious deformity was temporal depression and this remained to be the most obvious deformity after surgery. There was a good overall correction of the presenting deformities with a decline in the mean score preoperatively from 4.49-1.13 postoperatively. There was a significant weak correlation between pre- and postoperative score only for hypotelorism. This indicates that the severity of the initial disease is not a major contributor to the final surgical result. Furthermore, surgical outcome seemed to be stable over time and was not influenced by the timing of surgery when surgery was scheduled between the ages of 6-15 months. Early craniofacial correction for trigonocephaly results in a stable, acceptable aesthetic result on which the initial deformity has little effect. The most common associated craniofacial characteristics are well- to very well-corrected when surgery is performed within the first 6-15 months. Main focus of deformity on short and long term remains the temporal depression, and thus requires extra attention during surgery.

Nell-1-induced bone regeneration in calvarial defects

Many craniofacial birth defects contain skeletal components requiring bone grafting. We previously identified the novel secreted osteogenic molecule NELL-1, first noted to be overexpressed during premature bone formation in calvarial sutures of craniosynostosis patients. Nell-1 overexpression significantly increases differentiation and mineralization selectively in osteoblasts, while newborn Nell-1 transgenic mice significantly increase premature bone formation in calvarial sutures. In the current study, cultured calvarial explants isolated from Nell-1 transgenic newborn mice (with mild sagittal synostosis) demonstrated continuous bone growth and overlapping sagittal sutures. Further investigation into gene expression cascades revealed that fibroblast growth factor-2 and transforming growth factor-beta1 stimulated Nell-1 expression, whereas bone morphogenetic protein (BMP)-2 had no direct effect. Additionally, Nell-1-induced osteogenesis in MC3T3-E1 osteoblasts through reduction in the expression of early up-regulated osteogenic regulators (OSX and ALP) but induction of later markers (OPN and OCN). Grafting Nell-1 protein-coated PLGA scaffolds into rat calvarial defects revealed the osteogenic potential of Nell-1 to induce bone regeneration equivalent to BMP-2, whereas immunohistochemistry indicated that Nell-1 reduced osterix-producing cells and increased bone sialoprotein, osteocalcin, and BMP-7 expression. Insights into Nell-1-regulated osteogenesis coupled with its ability to stimulate bone regeneration revealed a potential therapeutic role and an alternative to the currently accepted techniques for bone regeneration.

FGFR1 Pfeiffer syndrome without craniosynostosis: an additional case report

Pfeiffer syndrome is an autosomal dominant condition classically encompassing both craniosynostosis and digital abnormalities of the hands and feet. Individuals with Pfeiffer syndrome may have mutations within either fibroblast growth factor receptor 1 gene (FGFR1) or FGFR2. FGFR1 mutations often result in less severe craniofacial involvement and hand abnormalities. We report a four-generation family with an FGFR1 P252R mutation, who have typical hand and feet skeletal features of Pfeiffer syndrome without craniofacial involvement. This is the third family in the literature in which no family members have craniofacial features of Pfeiffer syndrome. The absence of craniosynostosis should not preclude the consideration of FGFR mutation analysis in cases in which digital features are characteristic of the craniosynostosis syndromes.

Phenotypic integration of neurocranium and brain

Evolutionary history of Mammalia provides strong evidence that the morphology of skull and brain change jointly in evolution. Formation and development of brain and skull co-occur and are dependent upon a series of morphogenetic and patterning processes driven by genes and their regulatory programs. Our current concept of skull and brain as separate tissues results in distinct analyses of these tissues by most researchers. In this study, we use 3D computed tomography and magnetic resonance images of pediatric individuals diagnosed with premature closure of cranial sutures (craniosynostosis) to investigate phenotypic relationships between the brain and skull. It has been demonstrated previously that the skull and brain acquire characteristic dysmorphologies in isolated craniosynostosis, but relatively little is known of the developmental interactions that produce these anomalies. Our comparative analysis of phenotypic integration of brain and skull in premature closure of the sagittal and the right coronal sutures demonstrates that brain and skull are strongly integrated and that the significant differences in patterns of association do not occur local to the prematurely closed suture. We posit that the current focus on the suture as the basis for this condition may identify a proximate, but not the ultimate cause for these conditions. Given that premature suture closure reduces the number of cranial bones, and that a persistent loss of skull bones is demonstrated over the approximately 150 million years of synapsid evolution, craniosynostosis may serve as an informative model for evolution of the mammalian skull.

Long-term aesthetic results of frontoorbital correction for frontal plagiocephaly

OBJECT

Long-term aesthetic results of craniofacial surgery for frontal plagiocephaly were evaluated by two observers who used a scoring system based on deformities typical for this type of craniosynostosis.

METHODS

In this retrospective study, pre- and postoperative photographs of 59 patients were scored for items typical of frontal plagiocephaly: shape of the forehead, orbital dystopia, and temporal depression. Each item was quantified as normal or absent (0 points), a mild deformity (1 point) or a severe deformity (2 points). Preoperatively, the most obvious deformity was the shape of the forehead, whereas postoperatively temporal retrusion was the main deformity. There was a good overall correction of the presenting deformities, with a decline in the mean score from 3.7 to 0.86. There was a statistically significant weak correlation between pre- and postoperative scores for orbital dystopia alone. This finding indicates that the severity of the initial disease is not a major contributor to the final result. Furthermore, the surgical outcome seemed to be stable over time and was not influenced by the timing of surgery if it took place when the children were between 6 and 15 months of age.

CONCLUSIONS

Early craniofacial correction for frontal plagiocephaly results in a stable, acceptable aesthetic outcome on which the initial deformity has little effect. The most common associated craniofacial characteristics are corrected well to very well when surgery is performed within the first 6 to 15 months of life. The main focus of the deformity in both the short and long-term remains the temporal depression, and thus it requires extra attention during surgery.

Linking Antley–Bixler syndrome and congenital adrenal hyperplasia: A novel case of P450 oxidoreductase deficiency

The Antley-Bixler syndrome (ABS) is a multiple congenital malformation syndrome with craniosynostosis, radiohumeral synostosis, femoral bowing, choanal atresia or stenosis, joint contractures, urogenital abnormalities and, often, early death. Autosomal recessive and dominant inheritance have been postulated, as has fluconazole teratogenesis. Mutations in POR (P450 (cytochrome) oxidoreductase, an essential electron donor to enzymes participating in cholesterol biosynthesis), have been identified in some patients with the ABS phenotype. Recent evidence suggests that these mutations cause attenuated steroid hydroxylation, which in turn, causes congenital adrenal hyperplasia (CAH) with ambiguous genitalia in both sexes and glucocorticoid deficiency. Here, we report on a new patient with findings of both ABS and CAH that further illustrates how low maternal estriol at prenatal screening can serve as a marker steroid facilitating early diagnosis.

A newly recognized, likely autosomal recessive syndrome comprising agammaglobulinemia, microcephaly, craniosynostosis, severe dermatitis, and other features

We present a novel, likely autosomal recessive, multi-system disorder seen in three siblings, two males and one female, born to nonconsanguineous parents. The disease manifests as agammaglobulinemia with marked microcephaly, significant developmental delay, craniosynostosis, a severe dermatitis, cleft palate, narrowing of the choanae, and blepharophimosis. The constellation of clinical signs seen in this family likely represents a new and recognizable form of agammaglobulinemia due to a defect in early B-cell maturation.

Genotype-epigenotype-phenotype correlations in females with frontometaphyseal dysplasia

Frontometaphyseal dysplasia (FMD) belongs to a group of overlapping skeletal dysplasias, the common molecular basis of which are mutations of FLNA, the gene encoding filamin A. The nature of the mutation has been considered the major determinant of the phenotype within this group that comprises the otopalatodigital syndromes (OPD1, OPD2) and Melnick-Needles syndrome besides FMD. However, to date the molecular pathomechanisms are not well understood. In FMD only few FLNA mutations have been reported which do not cluster in a specific region of the protein. We report on a novel de novo mutation 5182G --> T in exon 31 of the FLNA gene in a girl with manifestations of FMD and OPD1. This mutation is predicted to lead to the exchange of a highly conserved glycine residue at position 1,728 by cysteine (G1728C) in repeat 15 of the filamin A rod domain. In a second family with FMD, we identified a known mutation (S1186L) in a mother and her son. In contrast to most previous reports on manifesting females or carriers of the FLNA-related skeletal dysplasias, the affected females presented here showed only mild to moderate skewing of X-inactivation against the mutant allele. Our data may indicate that in females, genotype-phenotype correlation between certain FLNA mutations and OPD1 and FMD, respectively, is less strict than previously assumed. We propose that X-inactivation is an important epigenetic modifier of the phenotype in females with the FLNA-related skeletal dysplasias.

FBN1, TGFBR1, and the Marfan-craniosynostosis/mental retardation disorders revisited

The recent identification of TGFBR2 mutations in Marfan syndrome II (MFSII) [Mizuguchi et al. (2004); Nat Genet 36:855-860] and of TGFBR1 and TGFBR2 mutations in Loeys-Dietz aortic aneurysm syndrome (LDS) [Loeys et al. (2005); Nat Genet 37:275-281] [OMIM 609192] has provided direct evidence of abnormal signaling in transforming growth factors beta (TGF-beta) in the pathogenesis of Marfan syndrome (MFS). In light of this, we describe the phenotypes and genotypes of five individuals. Patient 1 had MFS and abnormal cranial dura. Patient 2 had severe early onset MFS and an abnormal skull. Patients 3 and 4 had probable Furlong syndrome (FS). Patient 5 had marfanoid (MD) features, mental retardation (MR), and a deletion of chromosome 15q21.1q21.3. All patients had a condition within the MFS, MD-craniosynostosis (CS) or MD-MR spectrum. The names of these entities may become redundant, and instead, come to be considered within the spectrum of TGF-beta signaling pathway disorders. Two recurrent heterozygous FBN1 mutations were found in Patients 1 and 2, and an identical novel heterozygous de novo TGFBR1 mutation was found in Patients 3 and 4, in whom altered fibrillin-1 processing was demonstrated previously [Milewicz et al. (2000); Am J Hum Genet 67:279]. A heterozygous FBN1 deletion was found in Patient 5. These findings support the notion that perturbation of extracellular matrix homeostasis and/or remodeling caused by abnormal TGF-beta signaling is the core pathogenetic mechanism in MFS and related entities including the MD-CS syndromes.

Ultrasound in the Diagnosis of Craniosynostosis

Diagnosis of craniosynostosis is based on clinical aspects but may be difficult in some cases where characteristic features are missing and radiographic imaging is necessary. In this context near-field high-frequency ultrasound has been used to evaluate the sonographic characteristics of synostotic sutures and its potential confirming the correct diagnosis. Sutures of 26 infants, aged 2-7 months, were investigated by ultrasound (Siemens Elegra, 7.5 MHz linear scanner). Sonographic features of synostotic sutures were correlated to CT imaging and compared to the sonographic and histopathological findings of normal cranial sutures. Hyperechogenic bridging of sutures with or without ridging were the characteristic aspects of synostotic sutures. All 26 patients could be reliable diagnosed showing partial (n = 21) or total fusion (n = 5) of one or more sutures consisting with craniosynostosis. Length of synostosis was identified exactly by sonography and imaging found to enable a classification of ultrastructural details of bony and soft tissue next to the synostotic suture. Ultrasound is a less expensive, nonradiating and easy-to-handle tool ensuring the diagnosis of craniosynostosis. Sonography offers the potential to be a standard investigation for infants with head deformities suspecting a suture pathology and has been therefore integrated in our craniofacial outpatient clinic as a daily routine method.

Quantifying Positional Plagiocephaly

The treatment of positional plagiocephaly is controversial. A confounding factor is the lack of a proven clinically viable measure to quantify severity and change in plagiocephaly. The use of anthropometric measurements is one proposed method. In this study, the reliability and validity for this method of measurement were investigated. Two clinicians independently recorded caliper measurements of cranial vault asymmetry (CVA) for infants referred for plagiocephaly or torticollis, and an unbiased observer recorded visual analysis scores during the same visit. CVA scores were assigned into three predetermined severity categories (normal CVA < 3 mm, mild/moderate CVA <or= 12 mm, moderate/severe CVA > 12 mm). CVA measurements and visual analysis scores were recorded for 71 and 54 infants, respectively. Intrarater reliability was established (kappa = 0.98, kappa = 0.99), but inter-rater reliability was not (kappa = 0.42). In addition, the inter-rater reliability for the severity categories based upon these measures was poor (kappa = 0.28) and failed to correlate to the visual analysis (kappa = 0.31). Development of a stable and meaningful measurement system for the extent of plagiocephaly is needed to allow scientific studies of the natural history of plagiocephaly and effectiveness of interventions.

Diagnosis of isolated sagittal synostosis: are radiographic studies necessary?

AIMS AND OBJECTIVES

Isolated sagittal synostosis can be diagnosed easily on clinical grounds. This study was designed to determine if children could be operated on based solely on a clinical diagnosis or whether such an approach would result in any potentially unnecessary surgeries.

MATERIALS AND METHODS

Records of 114 consecutive children operated on for isolated nonsyndromic sagittal synostosis over a 14-year period (1987-2000) were reviewed to see whether the clinical findings were in concordance with the intraoperative findings and histopathology of the sagittal suture.

RESULTS

The age at surgery ranged from 1.9 to 81.3 months (median 4.3 months). Preoperative skull radiographs were done in 78 children and computer tomography (CT) scans of the head in 12 children. One hundred percent of the skull radiographs and 83.3% of the CT scans were completed prior to referring the children to a pediatric neurosurgeon. CT scans confirmed the diagnosis in all patients in whom it was available. For the rest, pathology reports and/or operative records were available for 108 (94.7%) children and were confirmatory for sagittal craniosynostosis in all.

CONCLUSIONS

Accurate diagnosis of isolated sagittal synostosis can be made clinically, and operative correction can proceed without a need for radiological investigations, unless the clinical features are not completely typical. This approach could result in significantly reduced radiation exposure for the developing brain and could provide economic benefits to health care providers.