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Journal of Personalized Medicine Jun 2021Hereditary dentin defects can be categorized as a syndromic form predominantly related to osteogenesis imperfecta (OI) or isolated forms without other non-oral...
Hereditary dentin defects can be categorized as a syndromic form predominantly related to osteogenesis imperfecta (OI) or isolated forms without other non-oral phenotypes. Mutations in the gene encoding dentin sialophosphoprotein (DSPP) have been identified to cause dentinogenesis imperfecta (DGI) Types II and III and dentin dysplasia (DD) Type II. While DGI Type I is an OI-related syndromic phenotype caused mostly by monoallelic mutations in the genes encoding collagen type I alpha 1 chain () and collagen type I alpha 2 chain (). In this study, we recruited families with non-syndromic dentin defects and performed candidate gene sequencing for exons and exon/intron boundaries. Three unrelated Korean families were further analyzed by whole-exome sequencing due to the lack of the mutation, and heterozygous mutations were identified: c.3233G>A, p.(Gly1078Asp) in Family 1 and c.1171G>A, p.(Gly391Ser) in Family 2 and 3. Haplotype analysis revealed different disease alleles in Families 2 and 3, suggesting a mutational hotspot. We suggest expanding the molecular genetic etiology to include for isolated dentin defects in addition to .
PubMed: 34201399
DOI: 10.3390/jpm11060526 -
Journal of Clinical Research in... Dec 2022Odontochondrodysplasia (ODCD, OMIM #184260) is a rare, non-lethal skeletal dysplasia characterized by involvement of the spine and metaphyseal regions of the long bones,...
Odontochondrodysplasia (ODCD, OMIM #184260) is a rare, non-lethal skeletal dysplasia characterized by involvement of the spine and metaphyseal regions of the long bones, pulmonary hypoplasia, short stature, joint hypermobility, and dentinogenesis imperfecta. ODCD is inherited in an autosomal recessive fashion with an unknown frequency caused by mutations of the thyroid hormone receptor interactor 11 gene (; OMIM *604505). The gene encodes the Golgi microtubule-associated protein 210 (GMAP-210), which is an indispensable protein for the function of the Golgi apparatus. Mutations in also cause achondrogenesis type 1A (ACG1A). Null mutations of lead to ACG1A, also known as a lethal skeletal dysplasia, while hypomorphic mutations cause ODCD. Here we report a male child diagnosed as ODCD with a novel compound heterozygous mutation who presented with skeletal changes, short stature, dentinogenesis imperfecta, and facial dysmorphism resembling achondroplasia and hypochondroplasia.
PubMed: 34111908
DOI: 10.4274/jcrpe.galenos.2021.2021.0099 -
Journal of Oral and Maxillofacial... Mar 2021Dentinogenesis imperfecta (DGI) type II affects both primary and permanent dentitions and has the autosomal mode of inheritance. The affected teeth may appear as amber...
Dentinogenesis imperfecta (DGI) type II affects both primary and permanent dentitions and has the autosomal mode of inheritance. The affected teeth may appear as amber or gray because of chipping of enamel shortly after their eruption. Correct diagnosis and management are highly needed to restore the quality of oral health and to improve esthetics and masticatory functions. We present here a case of systematic and conservative dental approach in the management of a 7-year-old child having Dentinogenesis Imperfecta Type II (DGI Type II) with 1 ½ follow-up.
PubMed: 34083977
DOI: 10.4103/jomfp.JOMFP_172_20 -
PloS One 2021Dentin Sialoprotein (DSP) and phosphophoryn (PP) are two most dominant non-collagenous proteins in dentin, which are the cleavage products of the DSPP (dentin...
Dentin Sialoprotein (DSP) and phosphophoryn (PP) are two most dominant non-collagenous proteins in dentin, which are the cleavage products of the DSPP (dentin sialophosphoprotein) precursor protein. The absence of the DSPP gene in DSPP knock-out (KO) mice results in characteristics that are consistent with dentinogenesis imperfecta type III in humans. Symptoms include thin dentin, bigger pulp chamber with frequent pulp exposure as well as abnormal epithelial-mesenchymal interactions, and the appearance of chondrocyte-like cells in dental pulp. To better understand how DSPP influences tooth development and dentin formation, we used a bacterial artificial chromosome transgene construct (BAC-DSPP) that contained the complete DSPP gene and promoter to generate BAC-DSPP transgenic mice directly in a mouse DSPP KO background. Two BAC-DSPP transgenic mouse strains were generated and characterized. DSPP mRNA expression in BAC-DSPP Strain A incisors was similar to that from wild-type (wt) mice. DSPP mRNA expression in BAC-DSPP Strain B animals was only 10% that of wt mice. PP protein content in Strain A incisors was 25% of that found in wt mice, which was sufficient to completely rescue the DSPP KO defect in mineral density, since microCT dentin mineral density analysis in 21-day postnatal animal molars showed essentially identical mineral density in both strain A and wt mice. Strain B mouse incisors, with 5% PP expression, only partially rescued the DSPP KO defect in mineral density, as microCT scans of 21-day postnatal animal molars indicated a reduced dentin mineral density compared to wt mice, though the mineral density was still increased over that of DSPP KO. Furthermore, our findings showed that DSPP dosage in Strain A was sufficient to rescue the DSPP KO defect in terms of epithelial-mesenchymal interactions, odontoblast lineage maintenance, along with normal dentin thickness and normal mineral density while DSPP gene dosage in Strain B only partially rescued the aforementioned DSPP KO defect.
Topics: Animals; Chromosomes, Artificial, Bacterial; Collagen Type II; Dentin; Extracellular Matrix Proteins; Incisor; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Minerals; Phosphoproteins; RNA, Messenger; Sialoglycoproteins; Tooth; X-Ray Microtomography
PubMed: 34038418
DOI: 10.1371/journal.pone.0250429 -
Dentistry Journal Apr 2021Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and low bone mass, caused mainly by mutations in collagen type I encoding...
Osteogenesis imperfecta (OI) is a genetic disorder characterized by increased bone fragility and low bone mass, caused mainly by mutations in collagen type I encoding genes. The current study aimed to evaluate dentinogenesis imperfecta (DI), oral manifestations and caries status of OI children. Sixty-eight children (41 males, 27 females) aged from 3 to 17 years old (mean 9 ± 4.13) participated in the study. Participants were classified into three OI type groups (I-2 cases, III-31 cases and IV-35 cases). Clinical examination and an orthopantomogram were used to obtain prevalences and associations of DI, caries status, malocclusion, crossbite, open bite, eruption, impaction and missing teeth with OI. The prevalence of DI among OI patients was 47.1%, more common in OI type III than type IV. The yellow-brown discoloration type was more vulnerable to attrition than the opalescent-grey one in the primary dentition. OI seemed not to have a high risk of caries; the prevalence of caries was 69.1%. A high incidence of malocclusion, crossbite and open bite was observed. In-depth oral information would provide valuable data for better dental management in OI patients. Parents and general doctors should pay more attention to dental care to prevent caries and premature tooth loss.
PubMed: 33925433
DOI: 10.3390/dj9050049 -
Revista Medica de Chile Dec 2020Osteogenesis imperfecta (OI) is a rare group of genetic disorders affecting connective tissue, with consequent bone fragility, frequent fractures and skeletal deformity....
BACKGROUND
Osteogenesis imperfecta (OI) is a rare group of genetic disorders affecting connective tissue, with consequent bone fragility, frequent fractures and skeletal deformity. Depending on the type, patients can have blue sclera, dentinogenesis imperfecta, and hearing loss.
AIM
To determine the frequency, type and audiometric characteristics of hearing loss in a group of patients with OI.
MATERIAL AND METHODS
A prospective cohort study was completed. A clinical and diagnostic hearing evaluation with tympanometry, acoustic stapedial reflex, pure-tone and speech audiometry were performed.
RESULTS
Thirty patients completed the study; mean age of 22 years (range 6-63 years). Sixty seven percent had a type I OI. Overall, nine (30%) patients had hearing loss (15/60 ears). Of these, six had bilateral hearing loss. Of the 15 affected ears, six showed conductive hearing loss, five sensorineural hearing loss, and four mixed hearing loss. Patients with hearing loss were older than patients with normal hearing. Only one pediatric patient developed hearing loss. Of the ears without hearing loss, 13% did not have an acoustic stapedial reflex.
CONCLUSIONS
In this group of patients with OI, 30% had hearing loss and among those ears with normal hearing, 13% did not have an acoustic stapedial reflex. Patients with OI should be monitored for hearing loss.
Topics: Adolescent; Adult; Audiometry, Pure-Tone; Child; Deafness; Hearing Loss; Humans; Middle Aged; Osteogenesis Imperfecta; Prospective Studies; Young Adult
PubMed: 33844744
DOI: 10.4067/S0034-98872020001201781 -
Molecular Genetics & Genomic Medicine Jun 2021Osteogenesis imperfecta (OI) is a rare heritable bone disorder that is characterised by increased bone fragility and recurrent fractures. To date, only 19 OI patients...
BACKGROUND
Osteogenesis imperfecta (OI) is a rare heritable bone disorder that is characterised by increased bone fragility and recurrent fractures. To date, only 19 OI patients have been reported, as caused by BMP1 gene mutations, worldwide. Here, we report a patient with a BMP1 gene mutation to explore the relationship between genotype and phenotype, and the patient was followed up for 4 years.
METHODS
Detailed clinical features were collected, and BMP1 mutational analysis was performed by next-generation sequencing and Sanger sequencing.
RESULTS
The patient had recurrent fractures, low bone mass, bone deformities and growth retardation but did not have hearing loss or dentinogenesis imperfecta. Next-generation sequencing and Sanger sequencing revealed a heterozygous novel missense variant (c.362C>T in exon 3, p.Ala121Val) and a heterozygous novel deletion mutation (c.1252delA in exon 10, p.Ser418AlafsX22). The parents of the proband were heterozygous carriers of these mutations. The patient received regular weekly treatment of 70 mg oral alendronate for 3 years, and her BMD Z-score for the femur significantly increased from -1.3 to 0.9 at L1-4 and from -1.7 to -0.1. She had no fracture during 4 years of follow-up.
CONCLUSION
We discovered two heterozygous novel mutations in an OI patient with BMP1 gene mutations, expanding the spectrum of gene mutations in OI.
Topics: Alendronate; Bone Density Conservation Agents; Bone Morphogenetic Protein 1; Child; Female; Homozygote; Humans; Mutation, Missense; Osteogenesis Imperfecta
PubMed: 33818922
DOI: 10.1002/mgg3.1676 -
JBMR Plus Mar 2021(transport and Golgi organization-1 homolog) encodes a transmembrane protein, which is located at endoplasmic reticulum (ER) exit sites where it binds bulky cargo, such...
(transport and Golgi organization-1 homolog) encodes a transmembrane protein, which is located at endoplasmic reticulum (ER) exit sites where it binds bulky cargo, such as collagens, in the lumen and recruits membranes from the ER-Golgi intermediate compartment (ERGIC) to create an export route for cargo secretion. Mice lacking (murine TANGO1 orthologue) show defective secretion of numerous procollagens and lead to neonatal lethality due to insufficient bone mineralization. Recently, aberrant expression of truncated TANGO1 in humans has been shown to cause a mild-to-moderate severe collagenopathy associated with dentinogenesis imperfecta, short stature, skeletal abnormalities, diabetes mellitus, and mild intellectual disability. We now show for the first time that complete loss of TANGO1 results in human embryonic lethality with near-total bone loss and phenocopies the situation of mice. Whole-exome sequencing on genomic DNA (gDNA) of an aborted fetus of Indian descent revealed a homozygous 4-base pair (4-bp) deletion in that is heterozygously present in both healthy parents. Parental fibroblast studies showed decreased TANGO1 mRNA expression and protein levels. Type I collagen secretion and extracellular matrix organization were normal, supporting a threshold model for clinical phenotype development. As such, our report broadens the phenotypic and mutational spectrum of -related collagenopathies, and underscores the crucial role of TANGO1 for normal bone development, of which deficiency results in a severe-to-lethal form of osteochondrodysplasia. © 2021 American Society for Bone and Mineral Research © 2020 The Authors. published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.
PubMed: 33778321
DOI: 10.1002/jbm4.10451 -
Bone Jun 2021Dental anomalies in Osteogenesis imperfecta (OI), such as tooth discoloration, pulp obliteration (calcified dental pulp space), and taurodontism (enlarged dental pulp...
INTRODUCTION
Dental anomalies in Osteogenesis imperfecta (OI), such as tooth discoloration, pulp obliteration (calcified dental pulp space), and taurodontism (enlarged dental pulp space) vary between and within patients. To better understand the associations and variations in these anomalies, a cross-sectional study was designed to analyze the dental phenotype in OI patients at the individual tooth type.
METHOD
A cohort of 171 individuals with OI type I, III and IV, aged 3-55 years, were recruited and evaluated for tooth discoloration, pulp obliteration, and taurodontism at the individual tooth level, using intraoral photographs and panoramic radiographs.
RESULTS
Genetic variants were identified in 154 of the participants. Patients with Helical α1 and α2 glycine substitutions presented the highest prevalence of tooth discoloration, while those with α1 Haploinsufficiency had the lowest (<10%). C-propeptide variants did not cause discoloration but resulted in the highest pulp obliteration prevalence (~%20). The prevalence of tooth discoloration and pulp obliteration was higher in OI types III and IV and increased with age. Tooth discoloration was mainly observed in teeth known to have thinner enamel (i.e. lower anterior), while pulp obliteration was most prevalent in the first molars. A significant association was observed between pulp obliteration and tooth discoloration, and both were associated with a lack of occlusal contact. Taurodontism was only found in permanent teeth and affected mostly first molars, and its prevalence decreased with age.
CONCLUSION
The dental phenotype evaluation at the tooth level revealed that different genetic variants and associated clinical phenotypes affect each tooth type differently, and genetic variants are better predictors of the dental phenotype than the type of OI. Our results also suggest that tooth discoloration is most likely an optical phenomenon inversely proportional to enamel thickness, and highly associated with pulp obliteration. In turn, pulp obliteration is proportional to patient age, it is associated with malocclusion and likely related to immature progressive dentin deposition. Taurodontism is an isolated phenomenon that is probably associated with delayed pulpal maturation.
Topics: Cross-Sectional Studies; Dentinogenesis Imperfecta; Humans; Osteogenesis Imperfecta; Phenotype; Tooth
PubMed: 33741542
DOI: 10.1016/j.bone.2021.115917 -
Frontiers in Cell and Developmental... 2021Hypoxia is a state of inadequate supply of oxygen. Increasing evidence indicates that a hypoxic environment is strongly associated with abnormal organ development....
Hypoxia is a state of inadequate supply of oxygen. Increasing evidence indicates that a hypoxic environment is strongly associated with abnormal organ development. Oxygen nanobubbles (ONBs) are newly developed nanomaterials that can deliver oxygen to developing tissues, including hypoxic cells. However, the mechanisms through which nanobubbles recover hypoxic tissues, such as developing tooth germs remain to be identified. In this study, tooth germs were cultured in various conditions: CO chamber, hypoxic chamber, and with 20% ONBs for 3 h. The target stages were at the cap stage (all soft tissue) and bell stage (hard tissue starts to form). Hypoxic tooth germs were recovered with 20% ONBs in the media, similar to the tooth germs incubated in a CO chamber (normoxic condition). The tooth germs under hypoxic conditions underwent apoptosis both at the cap and bell stages, and ONBs rescued the damaged tooth germs in both the cap and bell stages. Using kidney transplantation for hard tissue formation , amelogenesis and dentinogenesis imperfecta in hypoxic conditions at the bell stage were rescued with ONBs. Furthermore, glucose uptake by tooth germs was highly upregulated under hypoxic conditions, and was restored with ONBs to normoxia levels. Our findings indicate that the strategies to make use of ONBs for efficient oxygen targeted delivery can restore cellular processes, such as cell proliferation and apoptosis, glucose uptake, and hypomineralization in hypoxic environments.
PubMed: 33659251
DOI: 10.3389/fcell.2021.626224