Crouzon Syndrome With Acanthosis Nigricans Research Articles

Speech and Language Development, Hearing, and Feeding in Patients With Genetically Confirmed Crouzon Syndrome With Acanthosis Nigricans: A 36-Year Longitudinal Retrospective Review of Patients at the Oxford Craniofacial Unit.

Crouzon syndrome with acanthosis nigricans (CAN) is caused by the specific mutation c.1172C>A (p.Ala391Glu) in the fibroblast growth factor receptor 3 gene, and has an estimated prevalence of 1:1,000,000 births. Most cases occur de novo; however, autosomal dominant inheritance may occur. The clinical presentation typically includes craniosynostosis, midface and maxillary hypoplasia, choanal atresia/stenosis, hydrocephalus, and intracranial hypertension. Patients develop acanthosis nigricans, a hyperkeratotic skin disorder. The authors present the first known study to investigate the speech, language, hearing, and feeding of patients with CAN. A retrospective case-note review of patients with a genetically confirmed diagnosis of CAN attending the Oxford Craniofacial Unit during a 36-year period (1987-2023) was undertaken. Participants were 6 patients with genetically-confirmed CAN (5 females, 1 male), all cases arose de novo. All patients had craniosynostosis (n = 5/6 multisuture synostosis, n = 1/6 left unicoronal synostosis). Hydrocephalus was managed through ventriculoperitoneal shunt in 67% (n = 4/6) of patients, and 67% (n = 4/6) had a Chiari 1 malformation. Patients had a complex, multifactorial feeding history complicated by choanal atresia/stenosis (100%; n = 6/6), and significant midface hypoplasia. All patients required airway management through tracheostomy (83%; n = 5/6); and/or continuous positive airway pressure (67%; n = 4/6). All patients underwent adenotonsillectomy (100%; n = 6/6). Initial failure to thrive, low weight, and/or height were seen in 100% (n = 6/6) patients; 80% (n = 4/5) had reflux; 100% (n = 6/6) had nasogastric, or percutaneous endoscopic gastrostomy based feeding during their treatment journey. All patients had hearing loss (100%; n = 6/6). Early communication difficulties were common: receptive language disorder (50%; n = 3/6); expressive language disorder (50%; n = 3/6); and speech sound disorder in 50% (n = 3/6)-necessitating the use of Makaton in 80% of patients (n = 3/5). Patients with CAN experience significant respiratory, neurological, and structural obstacles to hearing, speech, language, and feeding. The authors present a recommended pathway for management to support patients in these domains.

Unravelling the pathogenesis of foramen magnum stenosis in patients with severe achondroplasia: a CT-based comparison with age-matched controls and FGFR3 craniosynostosis syndromes.

Foramen magnum(FM) stenosis can be responsible for acute and chronic damage to the cervicomedullary junction in children with achondroplasia. The bony anatomy and patterns of suture fusion of the FM in this context are incompletely understood, yet becoming increasingly important in the light of novel medical therapies for achondroplasia. The objective of this study was to describe and quantify bony anatomy and fusion patterns of FM stenosis in patients with achondroplasia using CT scans, comparing them to age-matched controls and other FGFR3 craniosynostosis patients. Patients with achondroplasia and severe FM stenosis, classified as achondroplasia foramen magnum score(AFMS) grades 3 and 4, were identified from a departmental operative database. All had pre-operative CT scans of the craniocervical junction. Measurements obtained comprised sagittal diameter (SD), transverse diameter (TD), foramen magnum area, and opisthion thickness. Anterior and posterior interoccipital synchondroses (AIOS and PIOS) were graded by the extent of fusion. These measurements were then compared with CT scans from 3 age-matched groups: the normal control group, children with Muenke syndrome, and children with Crouzon syndrome with acanthosis nigricans (CSAN). CT scans were reviewed in 23 cases of patients with achondroplasia, 23 normal controls, 20 Muenke, and 15 CSAN. Children with achondroplasia had significantly smaller sagittal diameter (mean 16.2 ± 2.4mm) compared to other groups (control 31.7 ± 2.4mm, p < 0.0001; Muenke 31.7 ± 3.5mm, p < 0.0001; and CSAN 23.1 ± 3.4mm, p < 0.0001) and transverse diameters (mean 14.3 ± 1.8mm) compared with other groups (control 26.5 ± 3.2mm, p < 0.0001; Muenke 24.1 ± 2.6mm, p < 0.0001; CSAN 19.1 ± 2.6mm, p < 0.0001). This translated into a surface area which was 3.4 times smaller in the achondroplasia group compared with the control group. The median grade of the AIOS fusion achondroplasia group was 3.0 (IQR 3.0-5.0), which was significantly higher compared with the control group (1.0, IQR 1.0-1.0, p < 0.0001), Muenke group (1.0, IQR 1.0-1.0, p < 0.0001), and CSAN (2.0, IQR 1.0-2.0, p < 0.0002). Median PIOS fusion grade was also highest in the achondroplasia group (5.0, IQR 4.0-5.0) compared with control (1.0, IQR 1.0-1.0, p < 0.0001), Muenke (2.5, IQR 1.3-3.0, p < 0.0001), and CSAN (4.0, IQR 4.0-4.0, p = 0.2). Distinct bony opisthion spurs projecting into the foramen magnum were seen in achondroplasia patients but not others, resulting in characteristic crescent and cloverleaf shapes. Patients with AFMS stages 3 and 4 have significantly reduced FM diameters, with surface area 3.4 times smaller than age-matched controls. This is associated with premature fusion of the AIOS and PIOS in comparison with controls and other FGFR3-related conditions. The presence of thickened opisthion bony spurs contributes to stenosis in achondroplasia. Understanding and quantifying bony changes at the FM of patients with achondroplasia will be important in the future quantitative evaluation of emerging medical therapies.

Clinical signs, interventions, and treatment course of three different treatment protocols in patients with Crouzon syndrome with acanthosis nigricans.

Crouzon syndrome with acanthosis nigricans (CAN) is a rare and clinically complex subtype of Crouzon syndrome. At three craniofacial centers, this multicenter study was undertaken to assess clinical signs in relation to the required interventions and treatment course in patients with CAN. A retrospective cohort study of CAN was performed to obtain information about the clinical treatment course of these patients. Three centers participated: Erasmus Medical Centre, Rotterdam, the Netherlands; John Radcliffe Hospital, Oxford, United Kingdom; and Hôpital Necker-Enfants Malades, Paris, France. Nineteen patients (5 males, 14 females) were included in the study. All children were operated on, with a mean of 2.2 surgeries per patient (range 1-6). Overall, the following procedures were performed: 23 vault expansions, 10 monobloc corrections, 6 midface surgeries, 11 foramen magnum decompressions, 29 CSF-diverting surgeries, 23 shunt-related interventions, and 6 endoscopic third ventriculostomies, 3 of which subsequently required a shunt. This study demonstrates that patients with the mutation c.1172C>A (p.Ala391Glu) in the FGFR3 gene have a severe disease trajectory, requiring multiple surgical procedures. The timing and order of interventions have changed among patients and centers. It was not possible to differentiate the effect of a more severe clinical presentation from the effect of treatment order on outcome.

Crouzon syndrome associated with acanthosis nigricans: Prenatal 2D and 3D ultrasound findings and postnatal 3D CT findings

Crouzon syndrome with acanthosis nigricans (CAN) is a very rare condition with an approximate prevalence of 1 per 1 million newborns. We add the first report on prenatal 2D and 3D ultrasound findings in CAN. In addition we present the postnatal 3D CT findings. The diagnosis was confirmed by molecular testing.

A Newborn with Acanthosis Nigricans: Can It Be Crouzon Syndrome with Acanthosis Nigricans?

Crouzon syndrome is a craniosynostosis syndrome, characterized by cloverleaf skull, hypertelorism, exophthalmos, external strabismus, parrot-beaked nose, short upper lip, hypoplastic maxilla, and mandibular prognathism. The 5% of individuals with Crouzon syndrome who have pigmentary changes in the skin are said to have Crouzon syndrome with acanthosis nigricans (CAN). Choanal atresia, hydrocephalus and the cranial features of Crouzon syndrome should suggest the diagnosis of CAN even before acanthosis appears. We present a 10-hour-old newborn who presented with bilateral choanal atresia, craniosynostosis and acanthosis nigricans. Molecular tests identified the FGFR3 Ala391Glu substitution confirming the diagnosis of CAN. Of the 35 cases of CAN reported in literature till date, only one child had acanthosis nigricans at birth. This is the first case from India to have been reported with this mutation.

Crouzon with acanthosis nigricans. Further delineation of the syndrome

Patients with Crouzon and acanthosis nigricans syndrome show craniofacial features similar to those observed in patients with classic Crouzon syndrome, in addition to acanthosis nigricans with peculiar characteristics. More severe physical manifestations, such as Chiari malformation, hydrocephalus, and atresia or stenosis of the choanas, which are unusual in individuals with classic Crouzon syndrome, are reported in these patients. The molecular abnormality associated with Crouzon syndrome with acanthosis nigricans (CAN) is a transition in the transmembrane domain of the FGFR3 gene that results in an Ala391Glu mutation. We describe two unrelated patients showing this mutation and compare their clinical features with those of other patients with CAN reported in the literature. In addition to craniosynostosis with crouzonoid facies and acanthosis nigricans (present in all patients), melanocytic nevi, choanal atresia or stenosis, hydrocephalus, Chiari malformations and oral abnormalities were observed in the majority of the 35 patients analyzed. Vertebral anomalies and conductive hearing loss were present with less frequency. Some characteristics considered typical of this condition (jaw cementomas, acanthomas and finger abnormalities) were absent in most of the patients.

Subtle radiographic findings of achondroplasia in patients with Crouzon syndrome with acanthosis nigricans due to an Ala391Glu substitution in FGFR3

A unique type of craniofacial dysostosis, Crouzon syndrome with acanthosis nigricans (CAN), has been attributed to a specific substitution (Ala391Glu) in the fibroblast growth factor receptor 3 (FGFR3) gene. At birth, individuals with this disorder have craniosynostosis, ocular proptosis, midface hypoplasia, choanal atresia, hydrocephalus, and they experience the onset of acanthosis nigricans during childhood. We report three cases and compare the clinical characteristics of our cases with the previously reported cases of this disorder. Since the Ala391Glu substitution in FGFR3 is close to the substitutions in the transmembrane domain that result in achondroplasia, we carefully reviewed the skeletal findings in six patients. We identified subtle radiographic findings of achondroplasia in all six cases including narrow sacrosciatic notches, short vertebral bodies, lack of the normal increase in interpediculate distance from the upper lumbar vertebrae caudally, and broad, short metacarpals and phalanges. Even before acanthosis nigricans appears, the presence of choanal atresia and hydrocephalus in an individual with features of Crouzon syndrome should suggest the diagnosis of CAN, and subtle skeletal findings can lend further support to this diagnosis.