Micrognathia is a severe craniofacial deformity affecting appearance and survival. Previous studies revealed that multiple factors involved in the osteogenesis of mandibular bone have contributed to micrognathia, but concerned little on factors other than osteogenesis. In the current study, we found that ectopic activation of Fgf8 by Osr2-cre in the presumptive mesenchyme for masseter tendon in mice led to micrognathia, masseter regression, and the disrupted patterning and differentiation of masseter tendon. Since Myf5-cre;Rosa26R-Fgf8 mice exhibited the normal masseter and mandibular bone, the possibility that the micrognathia and masseter regression resulted directly from the over-expressed Fgf8 was excluded. Further investigation disclosed that a series of chondrogenic markers were ectopically activated in the developing Osr2-cre;Rosa26R-Fgf8 masseter tendon, while the mechanical sensing in the masseter and mandibular bone was obviously reduced. Thus, it suggested that the micrognathia in Osr2-cre;Rosa26R-Fgf8 mice resulted secondarily from the reduced mechanical force transmitted to mandibular bone. Consistently, when tenogenic or myogenic components were deleted from the developing mandibles, both the micrognathia and masseter degeneration took place with the decreased mechanical sensing in mandibular bone, which verified that the loss of mechanical force transmitted by masseter tendon could result in micrognathia. Furthermore, it appeared that the micrognathia resulting from the disrupted tenogenesis was attributed to the impaired osteogenic specification, instead of the differentiation in the periosteal progenitors. Our findings disclose a novel mechanism for mandibular morphogenesis, and shed light on the prevention and treatment for micrognathia.
Mice ; Animals ; Micrognathism ; Masseter Muscle ; Mandible ; Osteogenesis

Cleft Lip ; Cleft Palate ; Dental Enamel Hypoplasia ; Humans ; Micrognathism

OBJECTIVE: To explore the clinical characteristics and genetic mutation in a family affected with Seckel syndrome. METHODS: Clinical data of the proband and his family members were collected. Potential mutations were detected by high-throughput sequencing and Sanger sequencing. RESULTS: The proband, a 7-year-and-3-month-old boy, has featured proportioned dwarfism, microcephaly, "bird head" appearance (narrow and backward forehead, prominent and protruded eyes, beak-shaped nose and microretrognathia), high-arched palate, enamel dysplasia, hypodontia, and mental retardation. His parents and two sisters were all phenotypically normal. The proband was found to harbor compound heterozygous c.1535T>A (p.L512X) and c.3346-5T>C (splicing) mutations of the CEP152 gene, which were respectively inherited from his mother and father. CONCLUSION The clinical features and genetic mutation of a case with Seckel syndrome were delineated. The newly discovered mutations have expanded the spectrum of CEP152 gene mutations.
Child ; Dwarfism ; Humans ; Intellectual Disability ; Male ; Microcephaly ; Micrognathism ; Mutation

OBJECTIVETo study the significance and principle of simultaneous orthodontics during mandibular distraction osteogenesis.

METHODSTotally 11 patients simultaneously underwent occlusal orthodontic treatment for 3-4 months during mandibular distraction osteogenesis. Square-wire and elastic loops were adapted to perform the orthodontics by ways of more frequent adjustment of orthodontic device than routine method.

RESULTSAll 11 patients with mandibular micronathia obtained the improved occlusion with their mandibular expected elongation, for instance, their open-bite and teeth displacement were partially corrected.

CONCLUSIONSimultanous orthodontics with mandibular distraction osteogenesis may improve the malocclusion, decrease the orthodontic time, and lead the mandibular distraction direction.

Adolescent ; Adult ; Female ; Humans ; Male ; Malocclusion ; complications ; therapy ; Mandible ; surgery ; Micrognathism ; complications ; surgery ; Orthodontics ; Osteogenesis, Distraction

OBJECTIVETo evaluate the effect of distraction osteogenesis for severe micrognathia by comparing the pre- and post-operative profile and mentolabial relationship.

METHODS16 cases underwent temporal-mandibular joint plasty and temporal fasciomuscular flap transfer. The mandibular distraction began at the 5th postoperative day at a rate of 0.8 mm a day, two times a day. Bony and soft tissue cephalometry were performed before and after operation. T-test was used to study the change after distraction osteogenesis.

RESULTSThere were significant differences in facial convexity, lower facial height, lower lip length, inter-labial distance, the ratio of lip to mental, the distance from lip to esthetic plane, the depth of mentolabial crease and the thickness of mental soft tissue.

CONCLUSIONSMandibular distraction osteogenesis can markedly improve the soft tissue profile of the middle and lower face for severe micrognathia.

Child ; Child, Preschool ; Facial Muscles ; pathology ; Humans ; Male ; Micrognathism ; pathology ; surgery ; Osteogenesis, Distraction ; Postoperative Period

Pierre Robin sequence (PRS), also called Robin sequence, is a congenital anomaly characterized by a triad of micrognathia, glossoptosis, and upper airway obstruction. Infants with PRS can present with varying degrees of respiratory difficulty secondary to upper airway obstruction. There has been no consensus for the treatment of upper airway obstruction in infants with PRS, but recent studies recommend attempting non-surgical interventions before surgical treatment. In this case report, we present 3 cases of infants diagnosed with PRS who showed persistent respiratory difficulties after birth. Before considering surgical intervention, insertion of a nasopharyngeal airway was attempted in these infants. Following this procedure, symptoms of upper airway obstruction were relieved, and all infants were discharged without surgical interventions; the nasopharyngeal airway was removed 1 to 2 months later. To date, no infant has shown signs of upper airway obstruction. Nasopharyngeal airway insertion is a highly effective and less invasive treatment option for infants with PRS. However, it is not widely known and used in Korea. Nasopharyngeal airway insertion can be preferentially considered before surgical intervention for upper airway obstruction in such infants.
Airway Obstruction ; Consensus ; Glossoptosis ; Humans ; Infant ; Korea ; Micrognathism ; Parturition ; Pierre Robin Syndrome

Pierre Robin sequence (PRS) is characterized by the triad of micrognathia, glossoptosis, and airway obstruction. PRS does not have a single pathogenesis, but rather is associated with multiple syndromes. This report presents the case of a 35-year-old woman with PRS and scoliosis. Among the syndromes related to PRS, cerebro-costo-mandibular syndrome (CCMS), which is characterized by posterior rib gap defects and vertebral anomalies, was suspected in this patient. However, no posterior rib gap defect was detected on radiological examinations. Although over 80 cases of CCMS have been reported to date, few cases of PRS with scoliosis alone have been reported. Therefore, this report demonstrated the clinical, radiological, and cephalometric characteristics of an adult patient with PRS and scoliosis, but without rib anomalies.
Adult ; Airway Obstruction ; Female ; Glossoptosis ; Humans ; Micrognathism ; Pierre Robin Syndrome ; Ribs ; Scoliosis

Humans ; Micrognathism ; complications ; surgery ; Obesity ; complications ; surgery ; Osteogenesis, Distraction ; Sleep Apnea, Obstructive ; etiology ; surgery

Trisomy 1 is a rare chromosomal anomaly and has never been reported in Korea. Clinical features of trisomy 1 include macrocephaly, prominent forehead, flat nasal bridge, low set ears, and micrognathia, all of which result in a very distinguishable facial structure. A child with trisomy 1 also suffers from mental retardation and/or developmental delays. In this case report, the child was diagnosed with de novo trisomy 1 without receiving any treatment until visiting our hospital. The child suffered from foot and ankle deformities, leading her unable to stand independently. Here we report the surgical treatment and rehabilitation treatment that enabled the child to walk independently.
Ankle ; Child* ; Congenital Abnormalities ; Ear ; Foot ; Forehead ; Humans ; Intellectual Disability ; Korea ; Megalencephaly ; Micrognathism ; Orthopedic Procedures ; Rehabilitation* ; Trisomy

A 19 month old girl with trisomy 18 is described. She showed loose folds of skin about the neck, a prominent occiput, a simian crease on both palms, epicanthal folds, acrocephaly, micrognathia, and unusual dermatologic features including total alopecia and no finger prints on either hands. Because of the simian crease on both palms, dermatoglyphics of both hands and total alopecia, a skin biopsy from the scalp and a chromosomal study were established at age 19-months, and an absence of hair follicles was observed, while peripheral blood lymphocytes demonstrated 47, XX, 4-18. To our knowledge, this would be the first recorded report on the dermatoglyphic pattern of Edwards syndrome in a Korean journal of dermatology.
Alopecia ; Biopsy ; Craniosynostoses ; Dermatoglyphics* ; Dermatology ; Female ; Fingers ; Hair Follicle ; Hand ; Humans ; Lymphocytes ; Micrognathism ; Neck ; Scalp ; Skin ; Trisomy*