Objective To make early diagnosis of IT15 gene mutation in a Wuhan juvenile-onset Huntington disease （HD） family, for providing them with genetic counseling, and making preparation for the further research on pathog...Objective To make early diagnosis of IT15 gene mutation in a Wuhan juvenile-onset Huntington disease （HD） family, for providing them with genetic counseling, and making preparation for the further research on pathogenesis and experimental therapy of HD. Methods According to the principle of informed consent, we extracted genomic DNA from peripheral blood samples and carried genetic diagnosis of pathogenic exon 1 of IT15 gene by modified touchdown PCR and DNA sequencing methods. Results Eight of twenty-five family members carried abnormal allele： Ⅲ10 Ⅲ12, IIIt4, Ⅳ3, and Ⅴ2 carded （CAG） 48, Ⅳ11 and Ⅳ12 carried （CAG） 67, and Ⅳ14 carried （CAG） 63, in contrast with the 8-25 CAG trinucleotides in the members of control group. Ⅳ14 carried 15 more CAG trinucleotides than her father Ⅲ10. Conclusion The results definitely confirm the diagnosis of HD and indicate the CAG trinucleotide repeat expansion of IT15 gene in this HD family. In addition, CAG expansion results in juvenile-onset and anticipation （characterized by earlier age of onset and increasing severity） of the patientⅣ12.展开更多
Background： Hypoparathyroidism-deafness-renal dysplasia （HDR） syndrome is an autosomal dominant disorder primarily caused by haploinsufficiency of GATA binding protein 3 （GATA3） gene mutations, and hearing loss i...Background： Hypoparathyroidism-deafness-renal dysplasia （HDR） syndrome is an autosomal dominant disorder primarily caused by haploinsufficiency of GATA binding protein 3 （GATA3） gene mutations, and hearing loss is the most frequent phenotypic feature. This study aimed at identifying the causative gene mutation for a three-generation Chinese t;amily with HDR syndrome and analyzing auditory phenotypes in all familial HDR syndrome cases. Methods： Three affected family members underwent otologic examinations, biochemistry tests, and other clinical evaluations. Targeted genes capture combining next-generation sequencing was pertbrmed within the family. Sanger sequencing was used to confirm the causative mutation. The auditory phenotypes of all reported familial H DR syndrome cases analyzed were provided. Results： In Chinese family 712 l, a heterozygous nonsense mutation c.826C〉T （p.R276＊） was identified in GA TA3. All the three affected members suffered from sensorineural deafness and hypocalcemia; however, renal dysplasia only appeared in the youngest patient. Furthermore, an overview of thirty HDR syndrome families with corresponding GATA3 mutations revealed that hearing impairment occurred earlier in the younger generation in at least nine familial cases （30%） and two thirds of them were found to carry premature stop mutations. Conclusions： This study highlights the phenotypic heterogeneity of HDR and points to a possible genetic anticipation in patients with HDR, which needs to be further investigated.展开更多
文摘Objective To make early diagnosis of IT15 gene mutation in a Wuhan juvenile-onset Huntington disease （HD） family, for providing them with genetic counseling, and making preparation for the further research on pathogenesis and experimental therapy of HD. Methods According to the principle of informed consent, we extracted genomic DNA from peripheral blood samples and carried genetic diagnosis of pathogenic exon 1 of IT15 gene by modified touchdown PCR and DNA sequencing methods. Results Eight of twenty-five family members carried abnormal allele： Ⅲ10 Ⅲ12, IIIt4, Ⅳ3, and Ⅴ2 carded （CAG） 48, Ⅳ11 and Ⅳ12 carried （CAG） 67, and Ⅳ14 carried （CAG） 63, in contrast with the 8-25 CAG trinucleotides in the members of control group. Ⅳ14 carried 15 more CAG trinucleotides than her father Ⅲ10. Conclusion The results definitely confirm the diagnosis of HD and indicate the CAG trinucleotide repeat expansion of IT15 gene in this HD family. In addition, CAG expansion results in juvenile-onset and anticipation （characterized by earlier age of onset and increasing severity） of the patientⅣ12.
文摘Background： Hypoparathyroidism-deafness-renal dysplasia （HDR） syndrome is an autosomal dominant disorder primarily caused by haploinsufficiency of GATA binding protein 3 （GATA3） gene mutations, and hearing loss is the most frequent phenotypic feature. This study aimed at identifying the causative gene mutation for a three-generation Chinese t;amily with HDR syndrome and analyzing auditory phenotypes in all familial HDR syndrome cases. Methods： Three affected family members underwent otologic examinations, biochemistry tests, and other clinical evaluations. Targeted genes capture combining next-generation sequencing was pertbrmed within the family. Sanger sequencing was used to confirm the causative mutation. The auditory phenotypes of all reported familial H DR syndrome cases analyzed were provided. Results： In Chinese family 712 l, a heterozygous nonsense mutation c.826C〉T （p.R276＊） was identified in GA TA3. All the three affected members suffered from sensorineural deafness and hypocalcemia; however, renal dysplasia only appeared in the youngest patient. Furthermore, an overview of thirty HDR syndrome families with corresponding GATA3 mutations revealed that hearing impairment occurred earlier in the younger generation in at least nine familial cases （30%） and two thirds of them were found to carry premature stop mutations. Conclusions： This study highlights the phenotypic heterogeneity of HDR and points to a possible genetic anticipation in patients with HDR, which needs to be further investigated.
