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

Insights into Craniofacial Development and Anomalies: Exploring Fgf Signaling in Zebrafish Models

PURPOSE OF REVIEW

To illustrate the value of using zebrafish to understand the role of the Fgf signaling pathway during craniofacial skeletal development under normal and pathological conditions.

RECENT FINDINGS

Recent data obtained from studies on zebrafish have demonstrated the genetic redundancy of Fgf signaling pathway and have identified new molecular partners of this signaling during the early stages of craniofacial skeletal development. Studies on zebrafish models demonstrate the involvement of the Fgf signaling pathway at every stage of craniofacial development. They particularly emphasize the central role of Fgf signaling pathway during the early stages of the development, which significantly impacts the formation of the various structures making up the craniofacial skeleton. This partly explains the craniofacial abnormalities observed in disorders associated with FGF signaling. Future research efforts should focus on investigating zebrafish Fgf signaling during more advanced stages, notably by establishing zebrafish models expressing mutations responsible for diseases such as craniosynostoses.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

What We Know About Intracranial Hypertension in Children With Syndromic Craniosynostosis

OBJECTIVE

A scoping review of literature about mechanisms leading to intracranial hypertension (ICH) in syndromic craniosynostosis (sCS) patients, followed by a narrative synopsis of whether cognitive and behavioral outcome in sCS is more related to genetic origins, rather than the result of ICH.

METHODS

The scoping review comprised of a search of keywords in EMBASE, MEDLINE, Web of science, Cochrane Central Register of Trials, and Google scholar databases. Abstracts were read and clinical articles were selected for full-text review and data were extracted using a structured template. A priori, the authors planned to analyze mechanistic questions about ICH in sCS by focusing on 2 key aspects, including (1) the criteria for determining ICH and (2) the role of component factors in the Monro-Kellie hypothesis/doctrine leading to ICH, that is, cerebral blood volume, cerebrospinal fluid (CSF), and the intracranial volume.

RESULTS

Of 1893 search results, 90 full-text articles met criteria for further analysis. (1) Invasive intracranial pressure measurements are the gold standard for determining ICH. Of noninvasive alternatives to determine ICH, ophthalmologic ones like fundoscopy and retinal thickness scans are the most researched. (2) The narrative review shows how the findings relate to ICH using the Monro-Kellie doctrine.

CONCLUSIONS

Development of ICH is influenced by different aspects of sCS: deflection of skull growth, obstructive sleep apnea, venous hypertension, obstruction of CSF flow, and possibly reduced CSF absorption. Problems in cognition and behavior are more likely because of genetic origin. Cortical thinning and problems in visual function are likely the result of ICH.

Crouzon syndrome with acanthosis nigricans: A case report and literature review

Crouzon’s syndrome with acanthosis nigricans is an autosomal dominant disease, with typical features of classic Crouzon craniosynostosis, verrucous hyperplasia, and hyperpigmentation of the skin. While several mutations in FGFR2 cause classic Crouzon syndrome, Crouzon syndrome with acanthosis nigricans results from a point mutation in the fibroblast growth factor receptor 3 gene (FGFR3). We report an 8-year-old Vietnamese girl diagnosed with Crouzon syndrome with acanthosis nigricans, showing typical clinical features, including a crouzonoid face and dark plaques on skin. Genetic testing showed a missense variation in FGFR3, associated with Crouzon syndrome with acanthosis nigricans. Following diagnosis, we treated acanthosis nigricans with 10% urea cream. This case study and literature review discusses the cutaneous manifestations and dermatological treatments, while demonstrating the importance of clinical examination and evaluation of the patient’s medical history during diagnosis. Our findings contribute to the global pool of data, providing practical insights into the manifestations of Crouzon syndrome.