scholarly journals Novel Mutations in GPR68 and SLC24A4 Cause Hypomaturation Amelogenesis Imperfecta

2021 ◽  
Vol 12 (1) ◽  
pp. 13
Author(s):  
Figen Seymen ◽  
Hong Zhang ◽  
Yelda Kasimoglu ◽  
Mine Koruyucu ◽  
James P. Simmer ◽  
...  

Amelogenesis imperfecta (AI) is a rare genetic condition affecting the quantity and/or quality of tooth enamel. Hypomaturation AI is characterized by brownish-yellow discoloration with increased opacity and poorly mineralized enamel prone to fracture and attrition. We recruited three families affected by hypomaturation AI and performed whole exome sequencing with selected individuals in each family. Bioinformatic analysis and Sanger sequencing identified and confirmed mutations and segregation in the families. Family 1 had a novel homozygous frameshift mutation in GPR68 gene (NM_003485.3:c.78_83delinsC, p.(Val27Cysfs*146)). Family 2 had a novel homozygous nonsense mutation in SLC24A4 gene (NM_153646.4:c.613C>T, NP_705932.2:p.(Arg205*)). Family 3 also had a homozygous missense mutation in SLC24A4 gene which was reported previously (c.437C>T, p.(Ala146Val)). This report not only expands the mutational spectrum of the AI-causing genes but also improves our understanding of normal and pathologic amelogenesis.

Genes ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1047 ◽  
Author(s):  
Lama Jaffal ◽  
Wissam H Joumaa ◽  
Alexandre Assi ◽  
Charles Helou ◽  
George Cherfan ◽  
...  

Aim: To identify disease-causing mutations in four Lebanese families: three families with Bardet–Biedl and one family with Usher syndrome (BBS and USH respectively), using next generation sequencing (NGS). Methods: We applied targeted NGS in two families and whole exome sequencing (WES) in two other families. Pathogenicity of candidate mutations was evaluated according to frequency, conservation, in silico prediction tools, segregation with disease, and compatibility with inheritance pattern. The presence of pathogenic variants was confirmed via Sanger sequencing followed by segregation analysis. Results: Most likely disease-causing mutations were identified in all included patients. In BBS patients, we found (M1): c.2258A > T, p. (Glu753Val) in BBS9, (M2): c.68T > C; p. (Leu23Pro) in ARL6, (M3): c.265_266delTT; p. (Leu89Valfs*11) and (M4): c.880T > G; p. (Tyr294Asp) in BBS12. A previously known variant (M5): c.551A > G; p. (Asp184Ser) was also detected in BBS5. In the USH patient, we found (M6): c.188A > C, p. (Tyr63Ser) in CLRN1. M2, M3, M4, and M6 were novel. All of the candidate mutations were shown to be likely disease-causing through our bioinformatic analysis. They also segregated with the corresponding phenotype in available family members. Conclusion: This study expanded the mutational spectrum and showed the genetic diversity of BBS and USH. It also spotlighted the efficiency of NGS techniques in revealing mutations underlying clinically and genetically heterogeneous disorders.


2021 ◽  
Vol 8 ◽  
Author(s):  
Muhammad Imran Naseer ◽  
Angham Abdulrahman Abdulkareem ◽  
Osama Yousef Muthaffar ◽  
Sameera Sogaty ◽  
Hiba Alkhatabi ◽  
...  

Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental defect that is characterized by reduced head circumference at birth along with non-progressive intellectual disability. Till date, 25 genes related to MCPH have been reported so far in humans. The ASPM (abnormal spindle-like, microcephaly-associated) gene is among the most frequently mutated MCPH gene. We studied three different families having primary microcephaly from different regions of Saudi Arabia. Whole exome sequencing (WES) and Sanger sequencing were done to identify the genetic defect. Collectively, three novel variants were identified in the ASPM gene from three different primary microcephaly families. Family 1, showed a deletion mutation leading to a frameshift mutation c.1003del. (p.Val335*) in exon 3 of the ASPM gene and family 2, also showed deletion mutation leading to frameshift mutation c.1047del (p.Gln349Hisfs*18), while in family 3, we identified a missense mutation c.5623A>G leading to a change in protein (p.Lys1875Glu) in exon 18 of the ASPM gene underlying the disorder. The identified respective mutations were ruled out in 100 healthy control samples. In conclusion, we found three novel mutations in the ASPM gene in Saudi families that will help to establish a disease database for specified mutations in Saudi population and will further help to identify strategies to tackle primary microcephaly in the kingdom.


2020 ◽  
Vol 99 (4) ◽  
pp. 410-418
Author(s):  
Y.J. Kim ◽  
J. Kang ◽  
F. Seymen ◽  
M. Koruyucu ◽  
H. Zhang ◽  
...  

Amelogenesis imperfecta (AI) is a collection of genetic disorders affecting the quality and/or quantity of tooth enamel. More than 20 genes are, so far, known to be responsible for this condition. In this study, we recruited 3 Turkish families with hypomaturation AI. Whole-exome sequence analyses identified disease-causing mutations in each proband, and these mutations cosegregated with the AI phenotype in all recruited members of each family. The AI-causing mutations in family 1 were a novel AMELX mutation [NM_182680.1:c.143T>C, p.(Leu48Ser)] in the proband and a novel homozygous MMP20 mutation [NM_004771.3:c.616G>A, p.(Asp206Asn)] in the mother of the proband. Previously reported compound heterozygous MMP20 mutations [NM_004771.3:c.103A>C, p.(Arg35=) and c.389C>T, p.(Thr130Ile)] caused the AI in family 2 and family 3. Minigene splicing analyses revealed that the AMELX missense mutation increased exonic definition of exon 4 and the MMP20 synonymous mutation decreased exonic definition of exon 1. These mutations would trigger an alteration of exon usage during RNA splicing, causing the enamel malformations. These results broaden our understanding of molecular genetic pathology of tooth enamel formation.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Zilin Zhong ◽  
Min Yan ◽  
Wan Sun ◽  
Zehua Wu ◽  
Liyun Han ◽  
...  

Abstract Retinitis pigmentosa (RP) is a heterogeneous set of hereditary eye diseases, characterized by selective death of photoreceptor cells in the retina, resulting in progressive visual impairment. Approximately 20–40% of RP cases are autosomal dominant RP (ADRP). In this study, a Chinese ADRP family previously localized to the region between D1S2819 and D1S2635 was sequenced via whole-exome sequencing and a variant c.1345C > G (p.R449G) was identified in PRPF3. The Sanger sequencing was performed in probands of additional 95 Chinese ADRP families to investigate the contribution of PRPF3 to ADRP in Chinese population and another variant c.1532A > C (p.H511P) was detected in one family. These two variants, co-segregate with RP in two families respectively and both variants are predicted to be pathological. This is the first report about the spectrum of PRPF3 mutations in Chinese population, leading to the identification of two novel PRPF3 mutations. Only three clustered mutations in PRPF3 have been identified so far in several populations and all are in exon 11. Our study expands the spectrum of PRPF3 mutations in RP. We also demonstrate that PRPF3 mutations are responsible for 2.08% of ADRP families in this cohort indicating that PRPF3 mutations might be relatively rare in Chinese ADRP patients.


2020 ◽  
Vol 36 (6) ◽  
Author(s):  
Muhammad Imran Naseer ◽  
Angham Abdulrahman Abdulkareem ◽  
Mohammed Mohammed Jan ◽  
Adeel G. Chaudhary ◽  
Mohammad H. Al-Qahtani

Objective: To study the causative variants in affected member of a Saudi family with Tay-Sachs disorder. This disorder includes paralysis, decreasing in attentiveness, seizures, blindness, motor deterioration progresses rapidly leading to a completely unresponsive state and a cherry-red spot visible on the eye. Methods: Whole exome sequencing (WES) and Sanger sequencing was performed to study the variant leading to the disease. Results: WES data analysis and Sanger sequencing validation, identifies a homozygous nonsense mutation c.1177C>T, p.Arg393Ter as a result in protein change. This mutation was also studied in 100 unrelated healthy controls. Conclusions: We detected homozygous mutation in HEXA gene that may lead to cause Tay-Sachs disorder. Moreover, explain the possibility that HEXA gene may play important role for multiple aspects of normal human neurodevelopment. doi: https://doi.org/10.12669/pjms.36.6.2579 How to cite this:Naseer MI, Abdulkareem AA, Jan MM, Chaudhary AG, Al-Qahtani MH. Whole exome sequencing reveals a homozygous nonsense mutation in HEXA gene leading to Tay-Sachs disease in Saudi Family. Pak J Med Sci. 2020;36(6):---------.  doi: https://doi.org/10.12669/pjms.36.6.2579 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


2015 ◽  
Vol 17 (3) ◽  
pp. 73
Author(s):  
Gina Murillo DDS, MSc ◽  
Fabián Morales DDS ◽  
Luis Gamboa DDS ◽  
Ana Maria Meza DDS ◽  
Ana Cristina López DDS

“Amelogenesis imperfecta” (AI) (prevalence up to 1 in 700) describes largely Mendelian enamel defects arising from gene mutations that present as structural  abnormalities of the temporary and permanent teeth as a result of defective enamel formation. AI has a wide range of clinical presentations and phenotypes and affects both sexes.  Despite increasing knowledge of the genetic mutations underlying AI there has been little research focussing on the effect of AI on the quality of life of AI patients. This study aimed to investigate the effects of AI on patient quality of life in a Costa Rican AI cohort. Affected family members were interviewed and their experiences used to develop an instrument (questionnaire) that was subsequently used to evaluate the impact of AI on their quality of life. 18 AI patients from 17 families were included in the study. Our findings showed that 100% had been teased and had suffered social rejection; 77.8% were concerned about their children´s inheritance and 66.7 % were concerned by the cost of treatment; 89% placed a high importance on their teeth. Results were not statistically significant when sorted by sex (p = 0.732).  The results of this study indicate that dental professionals need to understand AI not only as defective tooth enamel structure demanding specialist clinical management but also the negative impacts of the condition on the lives of their patients. This should be taken in to account when communicating with those affected.


2021 ◽  
Vol 14 (12) ◽  
pp. 1843-1851
Author(s):  
Muhammad Dawood ◽  
◽  
Taj Ud Din ◽  
Irfan Ullah Shah ◽  
Niamat Khan ◽  
...  

AIM: To investigate the genetic basis of autosomal recessive retinitis pigmentosa (arRP) in two consanguineous/ endogamous Pakistani families. METHODS: Whole exome sequencing (WES) was performed on genomic DNA samples of patients with arRP to identify disease causing mutations. Sanger sequencing was performed to confirm familial segregation of identified mutations, and potential pathogenicity was determined by predictions of the mutations’ functions. RESULTS: A novel homozygous frameshift mutation [NM_000440.2:c.1054delG, p. (Gln352Argfs*4); Chr5:g.149286886del (GRCh37)] in the PDE6A gene in an endogamous family and a novel homozygous splice site mutation [NM_033100.3:c.1168-1G>A, Chr10:g.85968484G>A (GRCh37)] in the CDHR1 gene in a consanguineous family were identified. The PDE6A variant p. (Gln352Argfs*4) was predicted to be deleterious or pathogenic, whilst the CDHR1 variant c.1168-1G>A was predicted to result in potential alteration of splicing. CONCLUSION: This study expands the spectrum of genetic variants for arRP in Pakistani families.


2017 ◽  
Vol 88 (5) ◽  
pp. 364-370 ◽  
Author(s):  
Lihong Liao ◽  
Hoong-Wei Gan ◽  
Vivian Hwa ◽  
Mehul Dattani ◽  
Andrew Dauber

Background: Short stature can be caused by mutations in a multitude of different genes. 3-M syndrome is a rare growth disorder marked by severe pre- and postnatal growth retardation along with subtle dysmorphic features. There have only been 2 prior reports of mutations in CCDC8 causing 3-M syndrome. Methods: Two patients presenting with mild short stature underwent whole exome sequencing. The mutation was confirmed via Sanger sequencing. We compare the clinical characteristics of our 2 patients to patients previously reported with mutations in the same gene. Results: Exome sequencing identified a homozygous frameshift mutation in CCDC8 in both patients. They presented with a much milder phenotype than previously described patients with the same mutation. Conclusion: In this study, we report a case of 2 sisters with relatively mild short stature who were found via exome sequencing to carry a previously reported homozygous mutation in CCDC8. These patients expand the anthropometric phenotype of 3-M syndrome and demonstrate the power of exome sequencing in the diagnosis of children with short stature. 3-M syndrome should be considered in children with mild skeletal abnormalities, normal/high growth hormone-IGF axis parameters, and normal intelligence.


Life ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 14
Author(s):  
Sajjad Karim ◽  
Samah Saharti ◽  
Nofe Alganmi ◽  
Zeenat Mirza ◽  
Ahmed Alfares ◽  
...  

Background: Oculocutaneous albinism (OCA) is an autosomal recessive disorder of low or missing pigmentation in the eyes, hair, and skin. Multiple types of OCA, including Hermansky-Pudlak syndrome 6 (HPS6), are distinguished by their genetic cause and pigmentation pattern. HPS6 is characterized by OCA, nose bleeding due to platelet dysfunction, and lysosome storage defect. To date, 25 disease-associated mutations have been reported in the HPS6 gene. Methods: DNA was extracted from proband, and whole-exome sequencing (WES) was performed using the Illumina NovaSeq platform. Bioinformatic analysis was done with a custom-designed filter pipeline to detect the causative variant. We did Sanger sequencing to confirm the candidate variant and segregation analysis, and protein-based structural analysis to evaluate the functional impact of variants. Result: Proband-based WES identified two novel homozygous mutations in HPS6 (double mutation, c.1136C>A and c.1789delG) in an OCA suspect. Sanger sequencing confirmed the WES results. Although no platelet and/or lysosome storage defect was detected in the patient or family, an oculocutaneous albinism diagnosis was established based on the HPS6 mutations. Structural analysis revealed the transformation of abnormalities at protein level for both nonsense and frameshift mutations in HPS6. Conclusion: To the best of our knowledge, the double mutation in HPS6 (p.Ser379Ter and p.Ala597GlnfsTer16) represents novel pathogenic variants, not described previously, which we report for the first time in the Saudi family. In silico analyses showed a significant impact on protein structure. WES should be used to identify HPS6 and/or other disease-associated genetic variants in Saudi Arabia, particularly in consanguineous families.


2020 ◽  
Vol 22 (10) ◽  
pp. 675-682 ◽  
Author(s):  
Jie Yin ◽  
Zhongping Qin ◽  
Kai Wu ◽  
Yufei Zhu ◽  
Landian Hu ◽  
...  

Backgrounds and Objective: Blue rubber bleb nevus syndrome (BRBN) or Bean syndrome is a rare Venous Malformation (VM)-associated disorder, which mostly affects the skin and gastrointestinal tract in early childhood. Somatic mutations in TEK have been identified from BRBN patients; however, the etiology of TEK mutation-negative patients of BRBN need further investigation. Method: Two unrelated sporadic BRBNs and one sporadic VM were firstly screened for any rare nonsilent mutation in TEK by Sanger sequencing and subsequently applied to whole-exome sequencing to identify underlying disease causative variants. Overexpression assay and immunoblotting were used to evaluate the functional effect of the candidate disease causative variants. Results: In the VM case, we identified the known causative somatic mutation in the TEK gene c.2740C>T (p.Leu914Phe). In the BRBN patients, we identified two rare germline variants in GLMN gene c.761C>G (p.Pro254Arg) and c.1630G>T(p.Glu544*). The GLMN-P254R-expressing and GLMN-E544X-expressing HUVECs exhibited increased phosphorylation of mTOR-Ser-2448 in comparison with GLMN-WTexpressing HUVECs in vitro. Conclusion: Our results demonstrated that rare germline variants in GLMN might contribute to the pathogenesis of BRBN. Moreover, abnormal mTOR signaling might be the pathogenesis mechanism underlying the dysfunction of GLMN protein.


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