scholarly journals Phenotypic variability and genetic characteristics of PRRT2-associated paroxysmal movement disorders in 13 Chinese families

Author(s):  
Lulu Wu ◽  
Xinyu Yang ◽  
Xiaocui Wang ◽  
Shuang Yu ◽  
Bin Yang

Abstract PRRT2-associated paroxysmal movement disorders (PRRT2-PxMDs) include paroxysmal kinesigenic dyskinesias (PKD), benign familial infantile epilepsy (BFIE), infantile convulsions and choreoathetosis (ICCA), episodic ataxia (EA), paroxysmal nonkinesiasgenic dyskinesias (PNKD), and, in addition, other childhood-onset movement disorders and different types of seizures may be caused by PRRT2 mutations, suggesting that the understanding of the spectrum of PRRT2-PxMDs is still evolving. We collected and analyzed retrospectively the clinical of children diagnosed with paroxysmal movement disorders by the Department of Neurology of Anhui Provincial Children's Hospital from January 2015 to June 2020. The genetic tests were performed in the probands and their family members. Thirteen children and their family members, 30 in total, were tested. Twenty six patients and 4 (13.34%) carriers from 13 families were identified, 14 (46.67%) were diagnosed with BIE, 7 (23.33%) with PKD, 2 (6.67%) with ICCA, 1 (3.33%) with epilepsy (focal), 1 (3.33%) with infantile spasm (IS), and 1 (3.33%)was diagnosed with PKD and PNKD, Eight different variants were identified in 13 families, and NM_145239.2:c.640-641insC was found in 4 families while recurrent mutation c.649dupC was not found. Three novel mutation, c.884G > C, c.865G > C, and c.-65-1G > C were identified in this study. This study confirmed that there is no clear genotype-phenotype correlation in patients with PRRT2-PxMDs, in addition, the clinical findings show variable phenotype within families, including the families affected due to the newly identified pathogenic variants in this study.

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Xiaojian Mao ◽  
Sichi Liu ◽  
Yunting Lin ◽  
Zhen Chen ◽  
Yongxian Shao ◽  
...  

Abstract Objective Hypophosphatasia (HPP) is an inherited disorder of defective skeletal mineralization caused by mutations in the ALPL gene that encodes the Tissue Non-specific Alkaline Phosphatase (TNSALP). It is subdivided into six forms depending on the age of onset: perinatal lethal, prenatal benign, infantile, childhood, adult, and odonto HPP. Among these, infantile HPP is characterized by early onset and high frequency of lethal outcome. Few studies have reported the phenotype and genetic characteristics of HPP in Chinese children. Case presentation Three forms of HPP were identified in four unrelated patients from four different Chinese families, including one lethal infantile (patient 1), two childhood (patient 2 and 3) and one odonto HPP (patient 4). Six variants in the ALPL gene were identified, including five missense mutations and one frameshift mutation. Of which, none were reported previously in the Chinese population, and two were novel (c.359G > C: p.G120A and c.1017dupG: p.H340AfsX3). Patient 1 carrying a novel homozygous (c.359G > C) mutation showed respiratory distress and pneumonia at first day of his life. He presented nearly negligible level of serum ALP activity, overall skeletal hypominaralization and died at 3 months old. Patient 2, 3 and 4 were compound heterozygotes with decreased serum ALP activity. Patient 2 and 3 presented premature loss of deciduous teeth, muscle weakness and bone pain, whereas patient 4 had early loss of deciduous teeth only. All four pedigrees exhibited autosomal recessive pattern of inheritance. Conclusions In this study, six mutations in the ALPL gene were found in four Chinese HPP patients, two of which were novel: c.359G > C in exon 5 and c.1017dupG in exon 10. Our results strongly indicated that the novel mutation c.359G > C might be disease-causing and associated with severe infantile form of HPP.


2016 ◽  
Vol 7 (4) ◽  
pp. 182-188 ◽  
Author(s):  
Steffen Syrbe ◽  
Boris S. Zhorov ◽  
Astrid Bertsche ◽  
Matthias K. Bernhard ◽  
Frauke Hornemann ◽  
...  

2019 ◽  
Author(s):  
Xiaojian Mao ◽  
Sichi Liu ◽  
Yunting Lin ◽  
Zhen Chen ◽  
Yongxian Shao ◽  
...  

Abstract Objective: Hypophosphatasia (HPP) is an inherited disorder of defective skeletal mineralization caused by mutations in the ALPL gene that encodes the Tissue Non-specific Alkaline Phosphatase (TNSALP). It is subdivided into six forms depending on the age of onset: perinatal lethal, prenatal benign, infantile, childhood, adult, and odonto HPP. Among these, infantile HPP is characterized by early onset and high frequency of lethal outcome. Few studies have reported the phenotype and genetic characteristics of HPP in Chinese children. Case presentation: Three forms of HPP were identified in four unrelated patients from four different Chinese families, including one lethal infantile (patient 1), two childhood (patient 2 and 3) and one odonto HPP (patient 4). Six variants in the ALPL gene were identified, including five missense mutations and one frameshift mutation. Of which, none were reported previously in the Chinese population, and two were novel (c.359G>C: p.G120A and c.1017dupG: p.H340AfsX3). Patient 1 carrying a novel homozygous (c.359G>C) mutation showed respiratory distress and pneumonia at first day of his life. He presented nearly negligible level of serum ALP activity, overall skeletal hypominaralization and died at 3 months old. Patient 2, 3 and 4 were compound heterozygotes with decreased serum ALP activity. Patient 2 and 3 presented premature loss of deciduous teeth, muscle weakness and bone pain, whereas patient 4 had early loss of deciduous teeth only. All four pedigrees exhibited autosomal recessive pattern of inheritance. Conclusions: In this study, six mutations in the ALPL gene were found in four Chinese HPP patients. Two of which were novel: c.359G>C in exon 5 and c.1017dupG in exon 10. Our results strongly indicated that the novel mutation c.359G>C might be disease-causing and associated with severe infantile form of HPP.


2019 ◽  
Author(s):  
Xiaojian Mao ◽  
Sichi Liu ◽  
Yunting Lin ◽  
Zhen Chen ◽  
Yongxian Shao ◽  
...  

Abstract Objective: Hypophosphatasia (HPP) is an inherited disorder of defective skeletal mineralization caused by mutations in the ALPL gene that encodes the Tissue Non-specific Alkaline Phosphatase (TNSALP). It is subdivided into six forms depending on the age of onset: perinatal lethal, prenatal benign, infantile, childhood, adult, and odonto HPP. Among these, infantile HPP is characterized by early onset and high frequency of lethal outcome. Few studies have reported the phenotype and genetic characteristics of HPP in Chinese children. Case presentation: Three forms of HPP were identified in four unrelated patients from four different Chinese families, including one lethal infantile (patient 1), two childhood (patient 2 and 3) and one odonto HPP (patient 4). Six variants in the ALPL gene were identified, including five missense mutations and one frameshift mutation. Of which, none were reported previously in the Chinese population, and two were novel (c.359G>C: p.G120A and c.1017dupG: p.H340AfsX3). Patient 1 carrying a novel homozygous (c.359G>C) mutation showed respiratory distress and pneumonia at first day of his life. He presented nearly negligible level of serum ALP activity, overall skeletal hypominaralization and died at 3 months old. Patient 2, 3 and 4 were compound heterozygotes with decreased serum ALP activity. Patient 2 and 3 presented premature loss of deciduous teeth, muscle weakness and bone pain, whereas patient 4 had early loss of deciduous teeth only. All four pedigrees exhibited autosomal recessive pattern of inheritance. Conclusions: In this study, six mutations in the ALPL gene were found in four Chinese HPP patients. Two of which were novel: c.359G>C in exon 5 and c.1017dupG in exon 10. Our results show that the novel mutation c.359G>C is strongly indicated to be disease-causing and associated with severe infantile form of HPP.


2019 ◽  
Author(s):  
Xiaojian Mao ◽  
Sichi Liu ◽  
Yunting Lin ◽  
Zhen Chen ◽  
Yongxian Shao ◽  
...  

Abstract Objective: Hypophosphatasia (HPP) is an inherited disorder of defective skeletal mineralization caused by mutations in the ALPL gene that encodes the Tissue Non-specific Alkaline Phosphatase (TNSALP). It is subdivided into six forms depending on the age of onset: perinatal lethal, prenatal benign, infantile, childhood, adult, and odonto HPP. Among these, infantile HPP is characterized by early onset and high frequency of lethal outcome. Few studies have reported the phenotype and genetic characteristics of HPP in Chinese children. Case presentation: Three forms of HPP were identified in four unrelated patients from four different Chinese families, including one lethal infantile (patient 1), two childhood (patient 2 and 3) and one odonto HPP (patient 4). Six variants in the ALPL gene were identified, including five missense mutations and one frameshift mutation. Of which, none were reported previously in the Chinese population, and two were novel (c.359G>C: p.G120A and c.1017dupG: p.H340AfsX3). Patient 1 carrying a novel homozygous (c.359G>C) mutation showed respiratory distress and pneumonia at first day of his life. He presented nearly negligible level of serum ALP activity, overall skeletal hypominaralization and died at 3 months old. Patient 2, 3 and 4 were compound heterozygotes with decreased serum ALP activity. Patient 2 and 3 presented premature loss of deciduous teeth, muscle weakness and bone pain, whereas patient 4 had early loss of deciduous teeth only. All four pedigrees exhibited autosomal recessive pattern of inheritance. Conclusions: In this study, six mutations in the ALPL gene were found in four Chinese HPP patients. Two of which were novel: c.359G>C in exon 5 and c.1017dupG in exon 10. Our results strongly indicated that the novel mutation c.359G>C might be disease-causing and associated with severe infantile form of HPP.


2019 ◽  
Vol 28 (2) ◽  
pp. 244-252 ◽  
Author(s):  
Yanqin Zhang ◽  
Jie Ding ◽  
Suxia Wang ◽  
Hongwen Zhang ◽  
Xuhui Zhong ◽  
...  

Abstract X-linked Alport syndrome (XLAS) is an inherited renal disease caused by mutations in COL4A5 gene. The c.2858G>T(p.(G953V)) in COL4A5 gene (rs78972735) has been considered pathogenic previously. However, there are conflicting interpretations of its pathogenicity recently. Here we presented 19 Chinese families, out of which 36 individuals (18 probands and 18 family members) carried the c.2858G>T(p.(G953V)) in COL4A5 gene. The clinical manifestations and genetic findings of them were analyzed. We found there were no clinical features of Alport syndrome not only in six probands with c.2858G>T(p.(G953V)) in COL4A5 plus pathogenic variants in other genes (e.g., WT1, ADCK4, NPHP1, TRPC6, COL4A4, and PAX2) but also in another six probands with only the c.2858G>T(p.(G953V)) variant. The other six probands with a combination of c.2858G>T(p.(G953V)) and another pathogenic variant in COL4A5 had XLAS. Eleven family members (11/18, nine females and two males) who had only the c.2858G>T(p.(G953V)) variant were asymptomatic. These two males (at age of 42 and 35 years) had normal result of urine analysis and no more clinical traits of Alport syndrome. We conclude c.2858G>T(p.(G953V)) in COL4A5 gene is not a pathogenic variant for XLAS. Individuals should not be diagnosed as XLAS only based on the detection of c.2858G>T(p.(G953V)) in COL4A5 gene.


2020 ◽  
Vol 5 (1) ◽  
pp. 19-26
Author(s):  
Guangming Fang ◽  
Jinxin Miao ◽  
Ying Peng ◽  
Yafei Zhai ◽  
Chuchu Wang ◽  
...  

Objective: The purpose of this work was to obtain the phenotypes and detect potential mutations in three Chinese patients with Marfan syndrome (MFS) or incomplete MFS phenotypes.Methods: Three unrelated patients with a definite or suspected clinical diagnosis of MFS and their family members were recruited for research. Genomic DNA was extracted from peripheral blood of these patients and their family members. All the exons were sequenced by next-generation sequencing and the variants were further validated by Sanger sequencing. The functional consequences of the mutations were analyzed with various genomic resources and bioinformatics tools.Results: Three FBN1 mutations were identified in the three patients, including one novel mutation (2125G > A) and two previously reported mutations (4786C > T and 6325C > T). It was interesting to note that the parents of these patients were normal as assessed by clinical features or genetic testing, but all these mutations were detected in their offspring, except for the variant 6325C > T. We also found that a few young members of the family of probands (proband 1 and proband 2) have exhibited no manifestations of MFS so far, although they carry the same disease-causing mutation.Conclusions: We found three FBN1 mutations in three unrelated Chinese families with MFS by genome sequencing, and the relationship between genotypes and phenotypes in MFS patients needs further exploration.


2017 ◽  
Vol 51 (3) ◽  
pp. 363-368 ◽  
Author(s):  
Tanja Planinsek Rucigaj ◽  
Matija Rijavec ◽  
Jovan Miljkovic ◽  
Julij Selb ◽  
Peter Korosec

Abstract Background Primary lymphoedema is a rare genetic disorder characterized by swelling of different parts of the body and highly heterogenic clinical presentation. Mutations in several causative genes characterize specific forms of the disease. FOXC2 mutations are associated with lymphoedema of lower extremities, usually distichiasis and late onset. Patients and methods Subjects from three generations of a family with lymphoedema of lower limbs without distichiasis were searched for mutations in the FOXC2 gene. Results All affected family members with lymphoedema of lower limbs without distichiasis, and still asymptomatic six years old girl from the same family, carried the same previously unreported insertion of adenosine (c.867insA) in FOXC2. Conclusions Identification of a novel mutation in the FOXC2 gene in affected family members of three generations with lymphoedema of lower limbs without distichiasis, highlights the high phenotypic variability caused by FOXC2 mutations.


Biomedicines ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 456
Author(s):  
Jan Henje Döring ◽  
Afshin Saffari ◽  
Thomas Bast ◽  
Knut Brockmann ◽  
Laura Ehrhardt ◽  
...  

Pathogenic variants in PRRT2, encoding the proline-rich transmembrane protein 2, have been associated with an evolving spectrum of paroxysmal neurologic disorders. Based on a cohort of children with PRRT2-related infantile epilepsy, this study aimed at delineating the broad clinical spectrum of PRRT2-associated phenotypes in these children and their relatives. Only a few recent larger cohort studies are on record and findings from single reports were not confirmed so far. We collected detailed genetic and phenotypic data of 40 previously unreported patients from 36 families. All patients had benign infantile epilepsy and harbored pathogenic variants in PRRT2 (core cohort). Clinical data of 62 family members were included, comprising a cohort of 102 individuals (extended cohort) with PRRT2-associated neurological disease. Additional phenotypes in the cohort of patients with benign sporadic and familial infantile epilepsy consist of movement disorders with paroxysmal kinesigenic dyskinesia in six patients, infantile-onset movement disorders in 2 of 40 individuals, and episodic ataxia after mild head trauma in one girl with bi-allelic variants in PRRT2. The same girl displayed a focal cortical dysplasia upon brain imaging. Familial hemiplegic migraine and migraine with aura were reported in nine families. A single individual developed epilepsy with continuous spikes and waves during sleep. In addition to known variants, we report the novel variant c.843G>T, p.(Trp281Cys) that co-segregated with benign infantile epilepsy and migraine in one family. Our study highlights the variability of clinical presentations of patients harboring pathogenic PRRT2 variants and expands the associated phenotypic spectrum.


Author(s):  
Salwa A. Musa ◽  
Areej A. Ibrahim ◽  
Samar S. Hassan ◽  
Matthew B Johnson ◽  
Asmahan T. Basheer ◽  
...  

Abstract Background Fanconi-Bickel syndrome (FBS) is a rare condition of carbohydrate metabolism, caused by a recessive defect in the facilitative glucose transporter GLUT2 encoded by the SLC2A2 gene and characterized by a wide spectrum of phenotypical features. There is a paucity of reported data on FBS from Sub-Saharan Africa. Here, we describe the clinical, biochemical and genetic characteristics of our patients with FBS from Sudan, a country with a high consanguinity rate. Patients & methods Eleven patients from ten unrelated Sudanese families were included. Clinical & biochemical data were documented and imaging studies done including bone survey and abdominal ultrasound. Liver biopsy was done to confirm the pathological diagnosis in 45% of cases and molecular genetics was performed through contribution with the Exeter genomics laboratory for ten patients. Results Reported consanguinity was 70% among our patients. Growth was significantly impaired at presentation with mean weights of (-5.3 ± 1.8) SD and heights (-5.4 ± 2.5) SD. Severe chest deformity was present in (27%) and all patients showed features of rickets at presentation. Three patients had neonatal diabetes requiring insulin therapy of which one has been reported before. Six families lost undiagnosed siblings with similar clinical presentations. We identified a total of four homozygous pathogenic SLC2A2 variants in our patients, one of whom had a novel mutation. Conclusions FBS is not uncommon in Sudan where there is a high rate of consanguinity. Many cases are likely missed because of variable presentation and lack of public and professionals’ awareness. This is the first series to describe this condition from Sub-Saharan Africa.


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