Mutations of the TWIST gene in the Saethre-Chotzen syndrome.

Saethre-Chotzen syndrome (acrocephalo-syndactyly type III, ACS III) is an autosomal dominant craniosynostosis with brachydactyly, soft tissue syndactyly and facial dysmorphism including ptosis, facial asymmetry and prominent ear crura. ACS III has been mapped to chromosome 7p21-22. Of interest, TWIST, the human counterpart of the murine Twist gene, has been localized on chromosome 7p21 as well. The Twist gene product is a transcription factor containing a basic helix-loop-helix (b-HLH) domain, required in head mesenchyme for cranial neural tube morphogenesis in mice. The co-localisation of ACS III and TWIST prompted us to screen ACS III patients for TWIST gene mutations especially as mice heterozygous for Twist null mutations displayed skull defects and duplication of hind leg digits. Here, we report 21-bp insertions and nonsense mutations of the TWIST gene (S127X, E130X) in seven ACS III probands and describe impairment of head mesenchyme induction by TWIST as a novel pathophysiological mechanism in human craniosynostoses.

Paclitaxel-hyaluronic acid for intravesical therapy of bacillus Calmette-Guérin refractory carcinoma in situ of the bladder: results of a phase I study.

PURPOSE: Carcinoma in situ represents high grade anaplasia of the bladder mucosa. Intravesical immunotherapy with bacillus Calmette-Guérin is the gold standard treatment for patients with carcinoma in situ. Patients with carcinoma in situ refractory to bacillus Calmette-Guérin are candidates for major surgery such as radical cystectomy. We identified the maximum tolerated dose and the recommended dose, and evaluated the safety profile of paclitaxel-hyaluronic acid bioconjugate given by intravesical instillation to patients with carcinoma in situ refractory to bacillus Calmette-Guérin. MATERIALS AND METHODS: A total of 16 patients with carcinoma in situ refractory to bacillus Calmette-Guérin were enrolled in a phase I, open label, single institution study. A minimum of 3 eligible patients were included per dose level. Paclitaxel-hyaluronic acid solution (ONCOFID-P-B™) was administered for 6 consecutive weeks. The primary objective was to identify the maximum tolerated dose and the recommended dose. As secondary objectives the safety profile of ONCOFID-P-B, the pharmacokinetic profile after each instillation and the tumor response were also evaluated. RESULTS: No dose limiting toxicity occurred at any drug level evaluated. The plasma levels of the study drug were always below the lower limit of quantification at all tested doses after each instillation. A total of 11 adverse events were reported by 7 patients and 9 (60%) showed complete treatment response. CONCLUSIONS: Intravesical instillation of ONCOFID-P-B for carcinoma in situ refractory to bacillus Calmette-Guérin showed minimal toxicity and no systemic absorption in the first human intravesical clinical trial to our knowledge. Finally, satisfactory response rates were observed.

Increased calvaria cell differentiation and bone matrix formation induced by fibroblast growth factor receptor 2 mutations in Apert syndrome.

Apert syndrome, associated with fibroblast growth factor receptor (FGFR) 2 mutations, is characterized by premature fusion of cranial sutures. We analyzed proliferation and differentiation of calvaria cells derived from Apert infants and fetuses with FGFR-2 mutations. Histological analysis revealed premature ossification, increased extent of subperiosteal bone formation, and alkaline phosphatase- positive preosteoblastic cells in Apert fetal calvaria compared with age-matched controls. Preosteoblastic calvaria cells isolated from Apert infants and fetuses showed normal cell growth in basal conditions or in response to exogenous FGF-2. In contrast, the number of alkaline phosphatase- positive calvaria cells was fourfold higher than normal in mutant fetal calvaria cells with the most frequent Apert FGFR-2 mutation (Ser252Trp), suggesting increased maturation rate of cells in the osteoblastic lineage. Biochemical and Northern blot analyses also showed that the expression of alkaline phosphatase and type 1 collagen were 2-10-fold greater than normal in mutant fetal calvaria cells. The in vitro production of mineralized matrix formed by immortalized mutant fetal calvaria cells cultured in aggregates was also increased markedly compared with control immortalized fetal calvaria cells. The results show that Apert FGFR-2 mutations lead to an increase in the number of precursor cells that enter the osteogenic pathway, leading ultimately to increased subperiosteal bone matrix formation and premature calvaria ossification during fetal development, which establishes a connection between the altered genotype and cellular phenotype in Apert syndromic craniosynostosis.

Increased bone formation and osteoblastic cell phenotype in premature cranial suture ossification (craniosynostosis).

Craniosynostosis is a heterogeneous disorder characterized by premature fusion of the skull bone sutures. To evaluate the pathogenesis of premature cranial suture ossification in craniosynostosis, we have evaluated the histologic indices of bone formation and the characteristics of osteoblastic cells derived from normal and affected cranial sutures in 47 infants and children, aged 3-18 months, with nonsyndromic craniosynostosis. The histomorphometric analysis of normal and fused sutures showed an age-related decline in the extent of endosteal bone surface covered with osteoid and osteoblasts during postnatal suture ossification. Bone formation was 20-50% higher at 3-6 months of age in fused sutures compared with normal sutures in the same patients. Cells derived from normal and fused sutures displayed characteristics of the osteoblast phenotype in culture. Analysis of [3H]thymidine incorporation into DNA from 1-14 days of culture showed an age-related decrease in osteoblastic cell growth in both normal and affected sutures. The proliferation of osteoblastic cells isolated from fused sutures was similar at all ages to that of cells isolated from normal sutures in the same patients. In contrast, alkaline phosphatase activity and osteocalcin production by osteoblastic cells cultured in basal conditions and after stimulation with 1,25-dihydroxyvitamin D (1,25[OH]2D3), were 53-74% higher in fused sutures compared with cells isolated from normal sutures in the same patients. The results indicate that bone formation activity at the suture site is locally increased in craniosynostosis, and this disorder is associated with increased in vitro parameters of osteoblastic cell differentiation, suggesting that an increased maturation of osteoblastic cells at the site of the suture leads to the premature ossification in nonsyndromic craniosynostosis.

Effect of hypothalamic and pituitary irradiation on pubertal development in children with cranial tumors.

The purpose of the present study was to report on gonadotropin function and puberty of a large group of children treated by cranial irradiation for cranial and neck tumors and medulloblastoma. Forty-five children of pubertal age were investigated. The mean interval time since radiation was 5 2/12 yr. Gonadotropin and gonadal function were evaluated by clinical criteria, plasma sex steroids, and plasma LH and FSH responses to LRH. Puberty was complete or progressing normally in 31 cases and was abnormal in 14 cases. Severe gonadotropin deficiency, with lack of or slow progression of puberty and decreased LH and FSH responsiveness to LRH, was observed in 5 cases; 2 of these had moderately elevated plasma PRL levels. Secondary amenorrhea or lack of pubertal progression was found in 5 other cases. GH deficiency was associated with gonadotropin deficiency in 9 of these 10 cases. Adrenal function, estimated by basal dehydroisoepiandrosterone, dehydroisoepiandrosterone sulfate, and estrone, was normal according to pubic hair stages. In conclusion, complete or partial gonadotropin deficiency can be the consequence of cranial irradiation in children receiving 6000 rads or less. It is usually associated with GH deficiency. The site of the damage on the pituitary gland or the hypothalamus remains to be demonstrated.

Mutations within or upstream of the basic helix-loop-helix domain of the TWIST gene are specific to Saethre-Chotzen syndrome.

Saethre-Chotzen syndrome (ACS III) is an autosomal dominant craniosynostosis syndrome recently ascribed to mutations in the TWIST gene, a basic helix-loop-helix (b-HLH) transcription factor regulating head mesenchyme cell development during cranial neural tube formation in mouse. Studying a series of 22 unrelated ACS III patients, we have found TWIST mutations in 16/22 cases. Interestingly, these mutations consistently involved the b-HLH domain of the protein. Indeed, mutant genotypes included frameshift deletions/insertions, nonsense and missense mutations, either truncating or disrupting the b-HLH motif of the protein. This observation gives additional support to the view that most ACS III cases result from loss-of-function mutations at the TWIST locus. The P250R recurrent FGFR 3 mutation was found in 2/22 cases presenting mild clinical manifestations of the disease but 4/22 cases failed to harbour TWIST or FGFR 3 mutations. Clinical re-examination of patients carrying TWIST mutations failed to reveal correlations between the mutant genotype and severity of the phenotype. Finally, since no TWIST mutations were detected in 40 cases of isolated coronal craniosynostosis, the present study suggests that TWIST mutations are specific to Saethre-Chotzen syndrome.

Mutations in the basic domain and the loop-helix II junction of TWIST abolish DNA binding in Saethre-Chotzen syndrome.

Saethre-Chotzen syndrome is an autosomal dominant skull disorder resulting from premature fusion of coronal sutures (craniosynostosis). It is caused by mutations in the TWIST gene encoding a basic Helix-Loop-Helix transcription factor. Here we report on the identification of a novel mutation affecting a highly conserved residue of the basic domain. Unlike nonsense and missense mutations lying within helices, this mutation does not affect protein stability or heterodimerisation of TWIST with its partner E12. However, it does abolish TWIST binding capacity to a target E-box as efficiently as two missense mutations in the loop-helix II junction. By contrast, elongation of the loop through a 7 amino acid insertion appears not to hamper binding to the DNA target. We conclude that loss of TWIST protein function in Saethre-Chotzen patients can occur at three different levels, namely protein stability, dimerisation, and DNA binding and that the loop-helix II junction is essential for effective protein-DNA interaction.

Syndromal and nonsyndromal primary trigonocephaly: analysis of a series of 237 patients.

From a series of 1,713 patients with craniosynostosis hospitalized between 1976 and 1996, 237 propositi with metopic synostosis were analyzed. The prevalence of metopic synostosis was estimated in the order of 1 in 15,000 children. Family information was obtained from 184 propositi from 179 families. The male-to-female ratio was 3.3:1. There was no maternal or paternal age effect. A family history was obtained in 10 of the 179 families, giving a 5.6% figure of familial cases. The frequency of twinning was 7.8% with two concordances for metopic synostosis in two monozygotic twin pairs. The male-to-female ratio, the twinning frequency, and the proportion of familial cases in trigonocephaly are very similar to those observed in scaphocephaly, which also involves the longitudinal sutural system. Fetal exposure to valproic acid was noticed in eight cases. The series was divided into two groups: nonsyndromal trigonocephaly (n = 184) and trigonocephaly associated with other malformations (n = 53). The second group included 13 cases of well-delineated syndromes and 40 cases of trigonocephaly associated with one or more malformations, but without any known syndrome, that could be undelineated syndromes. These groups differed significantly in their mental prognosis.

Genetic study of nonsyndromic coronal craniosynostosis.

From a series of 1265 individuals with different craniosynostoses hospitalized between 1976 and 1993, 260 probands with nonsyndromic unilateral (181) or bilateral (79) coronal synostosis were analysed. The prevalence of craniosynostoses was estimated as 1 in 2100 children. In the group of coronal synostosis, family history was obtained on 192 probands in 180 pedigrees. The male:female ratio was 1:2. The average paternal age was 32.7 +/- 6.4 years, which is significantly higher than normal. In 26 of the 180 pedigrees, a high degree of familial aggregation was observed, giving a 14.4% figure of familial cases. The bicoronal synostoses were significantly more often familial than the unicoronal synostoses. Segregation analysis of these families leads to the conclusion that coronal synostosis is transmitted as a dominant disorder with 0.60 penetrance and 61% of sporadic cases.

Genetic study of scaphocephaly.

From a series of 1,408 patients with craniosynostosis hospitalized between 1976 and 1994, 561 probands with non-syndromal isolated sagittal synostosis were analyzed. The prevalence of sagittal synostosis was estimated in the order of 1 in 5,000 children. Family information was obtained from 373 probands distributed among 366 families. The male:female ratio was 3.5:1. There was no maternal or paternal age effect. In 22 of the 366 pedigrees, a high degree of familial aggregation was observed, giving a 6% figure of familial cases. Segregation analysis of 253 families indicates that sagittal synostosis is transmitted as a dominant disorder with 38% penetrance and 72% of sporadic cases. The frequency of twinning was 4.8% with only 1 concordance for sagittal synostosis in a monozygotic twin pair. The possibility of a mechanical pathogenesis in sporadic cases is discussed.

The influence of molecular weight on the biological activity of heparin like sulphated hyaluronic acids.

Sulphated hyaluronic acids having a sulphation degree of 3.5 per disaccharide unit, HyalS3.5, were prepared with different molecular weights corresponding to 21 x 10(3), 320 x 10(3) and 3500 x 10(3). The thrombin inhibition in plasma and in the presence of purified molecules, i.e. fibrinogen, antithrombin III (AT III) and heparin cofactor II (HC II), were studied for the three different MW compounds at different concentrations. The thrombin time in plasma depended on the length of the chain, and the two lower MW HyalS3.5 inhibited thrombin both by direct aspecific interaction and via HC II, whereas the activity of the highest MW compound was mainly related to the electrostatic interaction with HC II. The inactivation of FXa serine protease was only attributed to HyalS3.5-AT III complex.

Insidious craniosynostosis and chronic papilledema in childhood.

PURPOSE: We studied a case of chronic papilledema in a 5-year-old child with visual loss who presented no obvious cosmetic abnormalities. METHODS: Neuroradiologic investigations were suggestive of craniosynostosis. The child underwent decompressive cranial surgery. Postoperatively, the papilledema totally regressed, and visual acuity recovered to 20/20 in both eyes. RESULTS: The chronic papilledema was confirmed to be related to harmonious oxycephaly. CONCLUSION: Insidious craniosynostosis is an unusual cause of chronic papilledema in childhood. The papilledema may be resolved and visual loss prevented by surgery.

Occipital remodeling and suboccipital decompression in severe craniosynostosis associated with tonsillar herniation.

OBJECTIVE: The goal was to describe a surgical technique allowing occipital vault remodeling and suboccipital decompression in patients affected by multiple-suture synostosis presenting severe occipital flattening and chronic tonsillar herniation (CTH). METHODS: Four patients (two with Crouzon's syndrome, one with Kleeblattschädel, and one with complex craniosynostosis) presenting multiple-suture synostosis with severe occipital flattening, posterior fingerprint impressions, and CTH were operated on in the prone position. For three patients, occipital vault remodeling and suboccipital decompression without dural opening were performed; for one patient affected by Kleeblattschädel, an upper cervical laminectomy and dural opening were performed. All patients were studied with magnetic resonance imaging pre- and postoperatively. RESULTS: No complications were observed. In all cases, postoperative magnetic resonance imaging revealed good decompression of the craniocervical junction, with resolution of brain stem displacement. In one case, CTH recurred 15 months after surgery, although in a less severe form. CONCLUSION: In selected cases of complex or syndromic craniosynostosis with predominant posterior deformity and CTH, this technique was safe and useful in the management of cranial reconstruction, allowing posterior vault remodeling and prophylactic suboccipital decompression. After validation with a larger number of patients, it could prove to be a useful option in all cases of complex craniosynostosis with CTH in which a staged repair of the craniosynostosis is to be considered.

Prognosis for mental function in scaphocephaly.

Three hundred ninety-six children with scaphocephalies were prospectively studied to analyze the correlation between age, intracranial pressure (ICP), and mental function outcome. The ICP measurements and the early and late psychometric assessments were compared. The influence of surgery, when performed, was analyzed. In most cases, the mental function outcome of the patients was good whether or not they had undergone surgery. The mental level and the frequency of increased ICP both correlated with patient age. A correlation was found between the early and late psychometric assessments in all patients. Thus, the main predictive factor of mental function outcome appears to be the initial developmental level.

Brain abscesses in neonates. A study of 30 cases.

Since the introduction of ultrasonography and computerized tomography (CT) scanning, brain abscesses are found more frequently in cases of neonatal meningitis and septicemia, particularly when the offending pathogen is Proteus. Thirty cases of brain abscess in neonates are reported, 27 of which were caused by Proteus species infections. Twenty infants had meningitis and 13 had septicemia. Most of the abscesses were enormous, and multiple abscesses were observed in 17 cases. The frontal region was involved in 22 cases (12 unilaterally and 10 bilaterally). The ventricles were enlarged on the first CT scan in 13 cases. The abscesses were treated by aspiration and antibiotics in 25 cases, and by antibiotics alone in five. A shunt for hydrocephalus was necessary in 14 infants. Four infants died, three from the initial illness and one from a shunt complication. Sixteen children have seizures. Subsequent intelligence quotient (IQ) testing was performed in 22 children: eight (36%) have an IQ at or above 80 and eight have an IQ of less than 60. In the 17 children followed for more than 2 years, the proportion with an IQ at or above 80 fell to 24% (four cases). The absence of initial seizures, sterile cerebrospinal fluid, normal ventricles on CT scans, and early aspiration of the abscess seem to be factors portending a better prognosis in terms of epilepsy and mental sequelae.

Classification of previously unclassified cases of craniosynostosis.

Cases of craniosynostosis usually fall into well-demarcated categories: those related to a syndrome or those identified by a combination of suture involvement and morphological appearance. Between 1976 and 1995, 53 (3.6%) of 1474 cases in the craniofacial databank were assessed and designated as nonsyndromic but unclassifiable. The records and radiological studies obtained in these patients were retrospectively analyzed and comparisons were made with patients classified in the databank as having simple craniosynostoses. It proved possible to divide the formerly unclassifiable cases into two groups: those with "two-suture disease" (Group A) and a "complex" group (Group B) in which more than two sutures were affected. Group A consisted of 36 cases (68%) of patients presenting with clear evidence of simultaneous involvement of two sutures but with no progression over time to suggest a more diffuse pansynostosis. Suture involvement was as follows: 17 of 36 sagittal plus one coronal; seven of 36 sagittal and metopic; six of 36 sagittal plus one lambdoid; and six of 36 metopic plus one coronal. The only significant difference between the Group A cases and the cases of simple craniosynostoses was in the percentage requiring a second operation (24% vs. 5%, p < 0.0001). Group B consisted of 17 cases in which the patients presented at a slightly earlier age (mean 1 year) with severe morphological changes and multiple suture involvement. At the time of surgery, six of 17 patients showed large areas of lacunae within the cranial vault, making craniectomy the only option. In Group B, 10 of 17 patients displayed bilateral lambdoid plus sagittal suture involvement resulting in marked occipital recession posteriorly, whereas anteriorly in six of these 10 patients there was a massive frontal bone associated with posteriorly located coronal sutures. In contrast, there were also four patients in Group B with bilateral coronal plus metopic involvement resulting in a small frontal bone. There was a trend toward a lower intelligence quotient and a worse morphological outcome in the patients in Group B, but again the only result attaining statistical significance when compared to the databank was the rate of second operation (37.5 vs. 5%, p < 0.0001). "Two-suture synostosis" is a relatively straightforward condition and is treatable with standard craniosynostosis techniques. However, possibly as a result of surgical compromise when two sutures are involved, the rate of reoperation is far higher than in simple suture cases. In contrast, patients in the "complex" group presenting with severe multisuture involvement require a more tailor-made approach to their management that often entails a second procedure.

Intracranial pressure in craniostenosis.

In this study, intracranial pressure (ICP) was recorded with an epidural sensor for periods of 12 to 24 hours in 92 cases of craniosynostosis. Pre- and postoperative recordings were performed in 23 patients, and 55 children underwent preoperative psychometric testing. The ICP was found to be normal in one-third of the cases, was obviously elevated in one-third, and was borderline in one-third. Waves of increased ICP were recorded during rapid eye movement (REM) sleep. After surgery, ICP decreased progressively and returned to normal in several weeks. A significant statistical relationship was found between the patients' ICP and their mental level: the higher the ICP the lower the mental level. The regression curve of ICP as a function of age shows that ICP is maximal at the age of 6 years and decreases later. The significance of these results is discussed. The authors recommend that ICP be recorded in cases of craniosynostosis since it is of some help in deciding whether patients should undergo surgery.

Prognosis for mental function in Apert's syndrome.

The factors involved in the mental development of patients with Apert's syndrome were studied by the authors, focusing on the age of the patient at operation, associated brain malformations, and the quality of the family environment. Overall, 32% of patients with significant follow-up review had an intelligence quotient (IQ) greater than 70. Age at operation appeared to be the main factor associated with changes in mental development: final IQ was greater than 70 in 50% of patients operated on before 1 year of age versus only 7.1% in patients operated on later in life (p = 0.01). Malformations of the corpus callosum and size of the ventricles played no role in the final IQ, whereas anomalies of the septum pellucidum had a significant effect, with the proportion of patients with an IQ over 70 increasing more than twofold in patients with a normal septum compared with patients with septal anomalies (p < 0.04). Quality of the family environment was the third factor involved in intellectual achievement: only 12.5% of institutionalized children reached a normal IQ level compared to 39.3% of children from a normal family background.

Chronic tonsillar herniation in Crouzon's and Apert's syndromes: the role of premature synostosis of the lambdoid suture.

The incidence of chronic tonsillar herniation (CTH) was evaluated with magnetic resonance imaging in 44 patients with Crouzon's syndrome and 51 with Apert's syndrome; the incidence was 72.7% in Crouzon's syndrome and 1.9% in Apert's syndrome. All the patients with Crouzon's syndrome and progressive hydrocephalus had CTH, but of 32 individuals with Crouzon's syndrome and CTH, only 15 had progressive hydrocephalus. Five patients with Apert's syndrome were treated for progressive hydrocephalus; none had CTH. The patterns of suture closure in these two groups of patients were studied, and significant differences in coronal, sagittal, and lambdoid sutures were found between patients with Crouzon's and Apert's syndromes. In Crouzon's syndrome, significant differences in the pattern of lambdoid suture closure were found between the groups with and without CTH; in the group with CTH, the lambdoid closure appeared earlier. The authors propose that the high incidence of individuals with CTH who have Crouzon's syndrome is related to the premature synostosis of the lambdoid suture in the first 24 months of age.