Whole exome sequencing identifies an AMBN missense mutation causing severe autosomal-dominant amelogenesis imperfecta and dentin disorders

Tooth development is a complex process that involves precise and time-dependent orchestration of multiple genetic, molecular,and cellular interactions. Ameloblastin(AMBN, also named "amelin" or "sheathlin") is the second most abundant enamel matrix protein known to have a key role in amelogenesis. Amelogenesis imperfecta(AI [MIM: 104500]) refers to a genetically and phenotypically heterogeneous group of conditions characterized by inherited developmental enamel defects. The hereditary dentin disorders comprise a variety of autosomal-dominant genetic symptoms characterized by abnormal dentin structure affecting either the primary or both the primary and secondary teeth. The vital role of Ambn in amelogenesis has been confirmed experimentally using mouse models. Only two cases have been reported of mutations of AMBN associated with non-syndromic human AI. However, no AMBN missense mutations have been reported to be associated with both human AI and dentin disorders.We recruited one kindred with autosomal-dominant amelogenesis imperfecta(ADAI) and dentinogenesis imperfecta/dysplasia characterized by generalized severe enamel and dentin defects. Whole exome sequencing of the proband identified a novel heterozygous C-T point mutation at nucleotide position 1069 of the AMBN gene, causing a Pro to Ser mutation at the conserved amino acid position 357 of the protein. Exfoliated third molar teeth from the affected family members were found to have enamel and dentin of lower mineral density than control teeth, with thinner and easily fractured enamel, short and thick roots, and pulp obliteration. This study demonstrates, for the first time, that an AMBN missense mutation causes non-syndromic human AI and dentin disorders.

Mutations in human Piwi cause male infertility

Subject Code:C05Supported by the National Natural Science Foundation of China,a collaborative study led by Prof.Liu Mofang(刘默芳)from Shanghai Institute of Biochemistry and Cell Biology,Chinese Academy of Sciences and Prof.Shi Huijuan(施惠娟)from Shanghai Institute of Planned Parenthood Research。

An updated review on activated PI3 kinase delta syndrome(APDS)

Activated Phosphoinositide 3-kinase d syndrome(APDS)is a newly recognised primary immunodeficiency disease.It has currently been a hot topic of clinical research and new data are emerging regarding its pathogenesis,clinical manifestations and treatment.Patients with APDS syndrome have significant autoimmune manifestations and lymphoproliferation.It is important to differentiate APDS from the usual polygenic CVID in view of the availability of targeted therapy like mTOR inhibitors such as Rapamycin and selective PI3Kd inhibitors.We provide a comprehensive review on this interesting disorder focusing light on its etiology,genetic research and emerging therapy.