ESPE Abstracts

Objective: To diagnose a 2-month old boy with micrognathia and proptosis.

Method: We summarized the clinical manifestations of the patient. Blood tests and imaging examinations were performed. DNA was isolated from peripheral blood cells. Whole exosome sequencing (WES) was conducted. Copy number variation (CNV) and loss of heterozygosity (LOH) was analyzed by Affymetrix CytoScan.

Result: The patient was 2 months and 16 days old. He was found proptosis and not able to track objects with his eyes one month ago. His mother had gestational diabetes and subclinical hypothyroidism during pregnancy. His body weight was 4.5kg, and head circumference was 36 cm. Physical examination showed protruding eyes; premature fusion of lambdoidal suture, sagittal suture and frontal suture; frontal fontanelle 2cm*2cm; ocular hypertelorism; low-set ears; a high, narrow palate; a long philtrum; a small lower jaw; laryngeal stridor; crossed extensor reflex, Babinski's reflex and Moro reflex could not be triggered, while Knee-jerk reflex and incurvation reflex were observed; no abnormalities were found in his limbs, fingers, toes and vertebrate. His blood gas, liver function, kidney function, thyroid function, lactic acid level, pyruvic acid level, levels of serum amino acids, levels of urine organic acids, and serum acylcarnitine levels were all normal. Brain MR scan showed enlarged left ventricle and dilated pericerebral space. Echocardiography showed multiple atrial septal defects. His hearing was normal and he had no retinopathy. There was no CNV and LOH detected in his DNA. WES revealed a de novo heterozygous c.1024T>A mutation leading to a p.Cys342Ser mutation in the FGFR2 gene, which was a hotspot of mutation and reported to be related with Crouzon syndrome and Pfeiffer syndrome.

Conclusion: According the results above, this patient was diagnosed as Crouzon syndrome, which is a rare genetic disorder and characterized by craniosynostosis. This rare case suggests that the diagnosis of rare diseases should be made in combinations of clinical characterization, examinations and genetic analysis.