A systematic review on Treacher Collins syndrome: Correlation between molecular genetic findings and clinical severity.

Treacher Collins syndrome (TCS, OMIM: 154500) is a rare congenital craniofacial disorder that is caused by variants in the genes TCOF1, POLR1D, POLR1C, and POLR1B. Studies on the association between phenotypic variability and their relative variants are very limited. This systematic review summarized the 53 literatures from PubMed and Scopus to explore the potential TCS genotype-phenotype correlations with statistical analysis. Studies reporting both complete molecular genetics and clinical data were included. We identified that the molecular anomaly within TCOF1 (88.71%) accounted for most TCS cases. The only true hot spot for TCOF1 was detected in exon 24, with recurrent c.4369_4373delAAGAA variant is identified. While the hot spot for POLR1D, POLR1C, and POLR1B were identified in exons 3, 8, and 15, respectively. Our result suggested that the higher severity level was likely to be observed in Asian patients harboring TCOF1 variants rather than POLR1. Moreover, common 5-bp deletions tended to have a higher severity degree in comparison to any variants within exon 24 of TCOF1. In summary, this report suggested the relationship between genetic and clinical data in TCS. Our findings could be used as a reference for clinical diagnosis and further biological studies.

Description of Total Population Hospital Admissions for Treacher Collins Syndrome in Australia.

OBJECTIVE: To describe patterns and demographic characteristics of total-population hospital admissions with a diagnosis of Treacher Collins syndrome (TCS) in Australia. DATA SOURCE: Population summary data for inpatient hospitals admissions (public and private) with a principal diagnosis of TCS (ICD10-AM-Q87.04) were obtained from the Australian Institute of Health and Welfare National Hospital Morbidity Database for a 11-year period (2002-2013). MAIN OUTCOME MEASURES: The primary outcome was hospital separation rate (HSR), calculated by dividing the number of hospital separations by estimated resident population per year. Trends in HSR s adjusted for age and sex were investigated by negative binomial regression presented as annual percent change and the association of rates with age and sex was expressed as incidence rate ratio. RESULTS: In 244 admissions identified, we observed an increase of 4.55% (95% confidence interval [CI] -1.78, 11.29) in HSR's over the 11-year period. Rates were higher during infancy (1.87 [95% CI 1.42, 2.42]), declining markedly with increasing age. The average length of hospital stay was 6.09 days (95% CI 5.78, 6.40) per episode, but longer for females and infants. CONCLUSIONS: Findings indicate an increase in hospitalization rates, especially among infants and females which potentially relates to early airway intervention procedures possibly influenced by sex specific-disease severity and phenotypic variability of TCS. Awareness of the TCS phenotype and improved access to genetic testing may support more personalized and efficient care. Total-population administrative data offers a potential to better understand the health burden of rare craniofacial diseases.

Phenotype Analysis and Genetic Study of Chinese Patients With Treacher Collins Syndrome.

OBJECTIVE: The aim of this study was to confirm the pathogenic variants, explore the genotype-phenotype correlation and characteristics of Chinese patients with Treacher Collins syndrome (TCS). DESIGN: Clinical details of 3 TCS family cases and 2 sporadic cases were collected and analyzed. Whole-exome sequencing and Sanger sequencing were conducted to detect causative variants. SETTING: Tertiary clinical care. PATIENTS: This study included 8 patients clinically diagnosed with TCS who were from 3 familial cases and 2 sporadic cases. MAIN OUTCOME MEASURES: When filtering the database, variants were saved as rare variants if their frequency were less than 0.005 in the 1000 Genomes Project Database, the Exome Aggregation Consortium (ExAC) browser, and the Novogene database, or they would be removed as common ones. The pathogenic variants identified were verified by polymerase chain reaction. The sequencing results were analyzed by Chromas 2.1 software. RESULTS: Two novel pathogenic variants (NM_000356.3: c.537del and NM_000356.3: c.1965_1966dupGG) and 2 known pathogenic variants (NM_000356.3: c.1535del, NM_000356.3: c.4131_4135del) were identified within TCOF1 which are predicted to lead to premature termination codons resulting in a truncated protein. There was a known missense SNP (NM_015972.3: c.139G>A) within POLR1D. No phenotype-genotype correlation was observed. Instead, these 8 patients demonstrated the high genotypic and phenotypic heterogeneity of TCS. CONCLUSIONS: This study expands on the pathogenic gene pool of Chinese patients with TCS. Besides the great variation among patients which is similar to international reports, Chinese patients have their own characteristics in clinical phenotype and pathogenesis mutations.

Catel-Manzke syndrome without Manzke dysostosis.

Catel-Manzke syndrome is characterized by hand anomalies, Robin sequence, cardiac defects, joint hyperextensibility, and characteristic facial features. Approximately 40 patients with Catel-Manzke have been reported, all with the pathognomonic bilateral or unilateral hyperphalangy caused by an accessory bone between the second metacarpal and proximal phalanx known as Manzke dysostosis. Here we present the first case of molecularly confirmed Catel-Manzke syndrome with Robin sequence but without Manzke dysostosis.

Broad-spectrum next-generation sequencing-based diagnosis of a case of Nager syndrome.

BACKGROUND: Nager syndrome is a rare genetic syndrome characterized by craniofacial and preaxial limb anomalies. Haploinsufficiency of the SF3B4 gene has been identified as a significant reason for Nager syndrome. Treacher Collins syndrome (TCS) has similar facial features; however, the TCOF1, POLR1D, and POLR1C genes have been reported as the critical disease-causing genes. Similar phenotypes make it easy to misdiagnose. CASE REPORT: In this report, we have presented a case of one newborn with acrofacial dysostosis, who was first diagnosed with TCS. Expanded next-generation sequencing eventually detected a (c.1A>G) heterozygous mutation in the SF3B4 gene at chr1:149899651 that was confirmed by Sanger sequencing. Combined with his preaxial limb anomalies discovered after his death, a diagnosis of Nager syndrome was made. CONCLUSIONS: This report presents one patient with Nager syndrome who was initially misdiagnosed with TCS. Correct genetic testing will be beneficial to future prenatal diagnosis.

Treacher Collins syndrome: A novel TCOF1 mutation and monopodial stapes.

Treacher Collins syndrome (TCS: OMIM 154500) is an autosomal dominant craniofacial disorder belonging to the heterogeneous group of mandibulofacial dysostoses. OBJECTIVE: To investigate four Treacher Collins syndrome patients of the Sgaw Karen family living in Thailand. METHOD: Clinical examination, hearing tests, lateral cephalometric analyses, Computed tomography, whole exome sequencing and Sanger direct sequencing were performed. RESULTS: All of the patients affected with Treacher Collins syndrome carried a novel TCOF1 mutation (c.4138_4142del; p.Lys1380GlufsTer12), but clinically they did not have the typical facial gestalt of Treacher Collins syndrome, which includes downward-slanting palpebral fissures, colobomas of the lower eyelids, absence of eyelashes medial to the colobomas, malformed pinnae, hypoplastic zygomatic bones and mandibular hypoplasia. Lateral cephalometric analyses identified short anterior and posterior cranial bases, and hypoplastic maxilla and mandible. Computed tomography showed fusion of malleus and incus, sclerotic mastoid, hypoplastic middle ear space with a soft tissue remnant, dehiscence of facial nerve and monopodial stapes. CONCLUSION: Treacher Collins syndrome in Sgaw Karen patients has not been previously documented. This is the first report of monopodial stapes in a TCS patient who had a TCOF1 mutation. The absence of a common facial phenotype and/or the presence of monopodial stapes may be the effects of this novel TCOF1 mutation.

The final demise of Rodriguez lethal acrofacial dysostosis: A case report and review of the literature.

We evaluated a newborn with acrofacial dysostosis in whom a clinical diagnosis of Nager syndrome was entertained. Radiographs revealed hypoplasia of the scapulae and bilateral humeroradial synostosis, with absent ulna on the left and hypoplastic ulna on the right. The finding of bilateral humeroradial synostosis had not been seen in cases of Nager syndrome before and we considered other diagnoses. Humeroradial synostosis has been found in three cases of acrofacial dysostosis Rodriguez type, a syndrome characterized by mandibular hypoplasia, upper and lower extremity phocomelia, and oligodactyly of the upper limbs. More recently, haploinsufficiency of the SF3B4 gene has been identified as the cause of both Nager and Rodriguez syndrome, leading many to believe that Rodriguez syndrome represents a more severe end of a Nager syndrome spectrum. An SF3B4 mutation was found in our patient, prompting a review of the previous known cases of Rodriguez syndrome, which revealed no clustering of SF3B4 mutations, and four cases of Rodriguez syndrome with mutations identical to those in cases of Nager syndrome. Rodriguez syndrome was previously thought of as a lethal acrofacial dysostosis distinct from Nager syndrome. A number of more mild cases, as well as our case, intermediate between the two phenotypes, illustrate that Rodriguez syndrome is a severe manifestation of Nager syndrome, and is not lethal with aggressive medical care.

Prenatal diagnosis of micrognathia in 41 fetuses: Retrospective analysis of outcome and genetic etiologies.

Fetal micrognathia can be detected early in pregnancy. Prognosis of micrognathia depends on the risk of respiratory distress at birth and on the long-term risk of intellectual disability. The purpose of this study was to evaluate the long-term prognosis of fetuses with prenatal diagnosis of micrognathia by estimating the prevalence and the severity of confirmed genetic diagnosis in our cohort. Our retrospective study included 41 fetuses with prenatal diagnosis of micrognathia referred to the multidisciplinary centers for prenatal diagnosis in Nice and Marseille, France, between 2006 and 2016. Fetal micrognathia was associated with cleft palate in 27 cases. A genetic cause was confirmed in 21 cases (67%). A chromosomal abnormality was present in 12 cases, including three copy-number variations diagnosed by array CGH. Monogenic disorders were identified in nine cases, most often after birth. Fetuses with family history of micrognathia or Pierre Robin sequence had a favorable outcome. Prognosis was good for the fetuses without associated findings and normal chromosomal analysis, with the exception of one case with a postnatal diagnosis of mandibulofacial dysostosis with microcephaly. Prognostic was poor for the fetuses with additional ultrasound anomalies, as only 5 out of 28 children had a good outcome. Prenatal diagnosis of micrognathia is an indicator of a possible fetal pathology justifying multidisciplinary management. Our study confirms the necessity of performing prenatal array CGH. Use of high-throughput gene sequencing in prenatal period could improve diagnostic performance, prenatal counseling, and adequate postnatal care.

Preferential Associated Malformation in Patients With Anotia and Microtia.

OBJECTIVE: Few epidemiological studies have investigated the external ear malformations anotia and microtia. The authors' study aimed to investigate the relationships between age, sex, type of microtia, and birth place and associated malformation as seen in 1 private Japanese clinic. METHODS: Cases of anotia/microtia that presented in Nagata Microtia and Reconstructive Plastic Surgery Clinic (Saitama, Japan) between 2005 and 2018 were included in the study. The authors identified 1896 patients with anotia/microtia with or without associated malformation. Most were primary cases, with some secondary reconstruction cases wherein the primary surgery was performed at another hospital. Cases were classified with Nagata classification; lobule type, small concha type, concha type, and anotia. Cryptotia was also observed in this study. RESULTS: Among the patients, 61.1% were male, 85.4% had unilateral defects (69.0% LB), and 59.1% had a right-sided defect. Most patients were less than 1 year old (15.0%) or 8 to 10 years old (5.5%-6.3%) on first examination, while 58% were from the Kanto region, including Tokyo. Regarding concomitant disorders, 32.7% had an accompanying malformation, while 13.3% had associated syndromes (eg, craniofacial microsomia, Treacher Collins syndrome). To conclude, in the authors' clinic, most cases of anotia/microtia were LB, unilateral, and seen in male patients. Information regarding several characteristic clinical features was obtained, especially that clefts and musculoskeletal deformities of the skull/face and jaw were the main accompanying malformations.

A novel approach using long-read sequencing and ddPCR to investigate gonadal mosaicism and estimate recurrence risk in two families with developmental disorders.

OBJECTIVE: De novo mutations contribute significantly to severe early-onset genetic disorders. Even if the mutation is apparently de novo, there is a recurrence risk due to parental germ line mosaicism, depending on in which gonadal generation the mutation occurred. METHODS: We demonstrate the power of using SMRT sequencing and ddPCR to determine parental origin and allele frequencies of de novo mutations in germ cells in two families whom had undergone assisted reproduction. RESULTS: In the first family, a TCOF1 variant c.3156C>T was identified in the proband with Treacher Collins syndrome. The variant affects splicing and was determined to be of paternal origin. It was present in <1% of the paternal germ cells, suggesting a very low recurrence risk. In the second family, the couple had undergone several unsuccessful pregnancies where a de novo mutation PTPN11 c.923A>C causing Noonan syndrome was identified. The variant was present in 40% of the paternal germ cells suggesting a high recurrence risk. CONCLUSIONS: Our findings highlight a successful strategy to identify the parental origin of mutations and to investigate the recurrence risk in couples that have undergone assisted reproduction with an unknown donor or in couples with gonadal mosaicism that will undergo preimplantation genetic diagnosis.

The Genetics Journey: A Case Report of a Genetic Diagnosis Made 30 Years Later.

Mandibulofacial dysostosis with microcephaly (MFDM) is a rare autosomal dominant condition that was first described in 2006. The causative gene, EFTUD2, identified in 2012. We report on a family that initially presented to a pediatric genetics clinic in the 1980s for evaluation of multiple congenital anomalies. Re-evaluation of one member thirty years later resulted in a phenotypic and molecularly confirmed diagnosis of MFDM. This family's clinical histories and the novel EFTUD2 variant identified, c.1297_1298delAT (p.Met433Valfs*17), add to the literature about MFDM. This case presented several genetic counseling challenges and highlights that "the patient" can be multiple family members. We discuss testing considerations for an unknown disorder complicated by the time constraint of the patient's daughter's pregnancy and how the diagnosis changed previously provided recurrence risks. Of note, 1) the 1980s clinic visit letters provided critical information about affected family members and 2) the patient's husband's internet search of his wife's clinical features also yielded the MFDM diagnosis, illustrating the power of the internet in the hands of patients. Ultimately, this case emphasizes the importance of re-evaluation given advances in genetics and the value of a genetic diagnosis for both patient care and risk determination for family members.

A Morphological Classification Scheme for the Mandibular Hypoplasia in Treacher Collins Syndrome.

BACKGROUND: Mandibular hypoplasia is a hallmark of Treacher Collins syndrome (TCS), and its severity accounts for significant functional morbidity. The purpose of this study is to develop a mandibular classification scheme. METHODS: A classification scheme was designed based on three-dimensional computed tomography (3D-CT) scans to assess 3 characteristic features: degree of condylar hypoplasia, mandibular plane angle (condylion-gonion-menton), and degree of retrognathia (sella-nasion-B point angle). Each category was graded from I to IV and a composite mandible classification was determined by the median value among the 3 component grades. RESULTS: Twenty patients with TCS, aged 1 month to 20 years, with at least one 3D-CT prior to mandibular surgery were studied. Overall, 33 3D-CTs were evaluated and ordered from least to most severe phenotype with 10 (30%) Grade 1 (least severe), 14 (42%) Grade 2, 7 (21%) Grade 3, and 2 (7%) Grade 4 (most severe). Seven patients had at least 2 longitudinal scans encompassing an average 5.7 (range 5-11) years of growth. Despite increasing age, mandibular classification (both components and composite) remained stable in those patients over time (P = 0.2182). CONCLUSION: The authors present a classification scheme for the TCS mandible based on degree of condylar hypoplasia, mandibular plane angle (Co-Go-Me angle), and retrognathia (SNB angle). While there is a natural progression of the mandibular morphology with age, patients followed longitudinally demonstrate consistency in their classification. Further work is needed to determine the classification scheme's validity, generalizability, and overall utility.

Mandibulofacial Dysostosis with Microcephaly: Mutation and Database Update.

Mandibulofacial dysostosis with microcephaly (MFDM) is a multiple malformation syndrome comprising microcephaly, craniofacial anomalies, hearing loss, dysmorphic features, and, in some cases, esophageal atresia. Haploinsufficiency of a spliceosomal GTPase, U5-116 kDa/EFTUD2, is responsible. Here, we review the molecular basis of MFDM in the 69 individuals described to date, and report mutations in 38 new individuals, bringing the total number of reported individuals to 107 individuals from 94 kindreds. Pathogenic EFTUD2 variants comprise 76 distinct mutations and seven microdeletions. Among point mutations, missense substitutions are infrequent (14 out of 76; 18%) relative to stop-gain (29 out of 76; 38%), and splicing (33 out of 76; 43%) mutations. Where known, mutation origin was de novo in 48 out of 64 individuals (75%), dominantly inherited in 12 out of 64 (19%), and due to proven germline mosaicism in four out of 64 (6%). Highly penetrant clinical features include, microcephaly, first and second arch craniofacial malformations, and hearing loss; esophageal atresia is present in an estimated ∼27%. Microcephaly is virtually universal in childhood, with some adults exhibiting late "catch-up" growth and normocephaly at maturity. Occasionally reported anomalies, include vestibular and ossicular malformations, reduced mouth opening, atrophy of cerebral white matter, structural brain malformations, and epibulbar dermoid. All reported EFTUD2 mutations can be found in the EFTUD2 mutation database (http://databases.lovd.nl/shared/genes/EFTUD2).

Treacher Collins syndrome: a clinical and molecular study based on a large series of patients.

PURPOSE: Treacher Collins/Franceschetti syndrome (TCS; OMIM 154500) is a disorder of craniofacial development belonging to the heterogeneous group of mandibulofacial dysostoses. TCS is classically characterized by bilateral mandibular and malar hypoplasia, downward-slanting palpebral fissures, and microtia. To date, three genes have been identified in TCS:,TCOF1, POLR1D, and POLR1C. METHODS: We report a clinical and extensive molecular study, including TCOF1, POLR1D, POLR1C, and EFTUD2 genes, in a series of 146 patients with TCS. Phenotype-genotype correlations were investigated for 19 clinical features, between TCOF1 and POLR1D, and the type of mutation or its localization in the TCOF1 gene. RESULTS: We identified 92/146 patients (63%) with a molecular anomaly within TCOF1, 9/146 (6%) within POLR1D, and none within POLR1C. Among the atypical negative patients (with intellectual disability and/or microcephaly), we identified four patients carrying a mutation in EFTUD2 and two patients with 5q32 deletion encompassing TCOF1 and CAMK2A in particular. Congenital cardiac defects occurred more frequently among patients with TCOF1 mutation (7/92, 8%) than reported in the literature. CONCLUSION: Even though TCOF1 and POLR1D were associated with extreme clinical variability, we found no phenotype-genotype correlation. In cases with a typical phenotype of TCS, 6/146 (4%) remained with an unidentified molecular defect.

Mandibular dysostosis without microphthalmia caused by OTX2 deletion.

Mutations in OTX2 are mostly identified in patients with anophthalmia/microphthalmia with variable severity. The OTX2 homeobox gene plays a crucial role in craniofacial morphogenesis during early embryo development. We report for the first time a patient with a mandibular dysostosis caused by a 120 kb deletion including the entire coding sequence of OTX2, identified by array CGH. No ocular malformations were identified after extended ophthalmologic examination. Our data refine the clinical spectrum associated with OTX2 mutations and suggests that OTX2 haploinsufficiency should be considered as a possible cause for isolated mandibular dysostosis. © 2016 Wiley Periodicals, Inc.

Array-CGH is an effective first-tier diagnostic test for EFTUD2-associated congenital mandibulofacial dysostosis with microcephaly.

Mandibulofacial dysostosis with microcephaly (MFDM) is a sporadic malformation syndrome with severe craniofacial abnormalities, microcephaly, developmental delay, and dysmorphic features. Most cases of clinically diagnosed MFDM remain genetically unexplained, and to the best of our knowledge a total of 35 patients, 31 different mutations, 4 deletions, and 6 reports have been published. Our proband was born at 36 weeks gestation with microcephaly, microcrania, cleft palate, severe retrognathia, oral and pharyngeal dysphagia, bilateral proximal radioulnar synostosis, 11 thoracic ribs, abnormal magnetic resonance imaging (MRI) findings including simplified gyral pattern and mild dilatation of the posterior bodies of the lateral ventricles secondary to thinning of the white matter, high-pitched cry due to unilateral vocal cord paralysis, and dysmorphic features. Array comparative genomic hybridization (aCGH) + single nucleotide polymorphism (SNP) analysis identified a likely de novo pathogenic deletion on chromosome 17q21.31, encompassing the EFTUD2 gene. Our case represents the fifth reported proband to have MFDM caused by small deletions involving EFTUD2. All known mutations involving EFTUD2 result in genetic haploinsufficiency, consistent with our proband's case as well. Her phenotypic features both overlap and expand on the clinical features of previously reported cases, and her genetic diagnosis also supports the use of aCGH as a first-tier testing option for this disorder.

Nager syndrome and Pierre Robin sequence.

Nager syndrome is considered a rare genetic syndrome characterized by craniofacial and radial anomalies. Pierre Robin sequence is a triad that includes micrognathia, cleft palate and glossoptosis. The present patient had typical findings of Nager syndrome and Pierre Robin sequence. He progressed to severe respiratory distress, requiring mechanical ventilation and tracheostomy. At 1 year and 11 months, he had episodes of cardiorespiratory arrest and died. In the literature review, we identified the clinical description of 44 patients with Nager syndrome. Among them, 93.1% had micrognathia, 38.6% cleft palate and 11.3% glossoptosis. Only one (2.3%) had all three features, as observed in the present patient. Therefore, despite the fact that the features of Pierre Robin sequence are common, there are few patients who have the complete triad. It is noteworthy, however, that they may be associated with respiratory distress, which may put the patient's life at risk.

Radioulnar Synostosis and Brain Abnormalities in a Patient With 17q21.31 Microdeletion Involving EFTUD2.

Mandibulofacial dysostosis with microcephaly is a rare syndromic craniofacial condition caused by heterozygous loss-of-function mutations of the EFTUD2 gene on 17q21.31. Thus far, the described musculoskeletal findings in patients with this condition include proximally placed or duplicated thumbs, overlapping toes, and toe syndactyly. We describe a severe case of a patient with a 17q21.31 microdeletion and many of the phenotypic features described in mandibulofacial dysostosis with microcephaly who had bilateral proximal radioulnar synostosis and brain abnormalities. This provides further evidence of the clinical overlap among mandibulofacial and acrofacial dysostoses syndromes and expands the phenotype of EFTUD2 haploinsufficiency due to larger deletions.