Maple syrup urine disease（枫糖尿症）

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检测编号：NA0170003


基因 BCKDHA 与疾病

BCKDHA, BCKDHB, DBT 这三个基因的表达产物结合成一个多酶复合体，代谢食物中的支链氨基酸亮氨酸、异亮氨酸和缬氨酸。这3个基因中任何一个突变都会造成机体无法代谢上述氨基酸，这些氨基酸及其副产品在体内堆积，对大脑及身体器官造成损害。

BCKDHA基因编码BCKD（支链α-酮酸脱氢酶多酶复合体）的α亚基，2个α亚基和2个β亚基组成BCKD的一个E1单元。BCKDHA基因已发现40多种突变，多数在经典型枫糖尿症患者中发现。这些突变大多是点突变，常见的突变位点是Y438N。

基因名称基因全名基因位置外显子个数 CDS长度
BCKDHA branched chain keto acid dehydrogenase E1, alpha polypeptide 19q13.1-q13.2 9 约1774 bp
基因摘要 The branched-chain alpha-keto acid (BCAA) dehydrogenase (BCKD) complex is an innter mitochondrial enzyme complex that catalyzes the second major step in the catabolism of the branched-chain amino acids leucine, isoleucine, and valine. The BCKD complex consists of three catalytic components: a heterotetrameric (alpha2-beta2) branched-chain alpha-keto acid decarboxylase (E1), a dihydrolipoyl transacylase (E2), and a dihydrolipoamide dehydrogenase (E3). This gene encodes the alpha subunit of the decarboxylase (E1) component. Mutations in this gene result in maple syrup urine disease, type IA. Multiple transcript variants encoding different isoforms have been found for this gene.[provided by RefSeq, Sep 2009].

基因 BCKDHB 与疾病

BCKDHA, BCKDHB, DBT 这三个基因的表达产物结合成一个多酶复合体，代谢食物中的支链氨基酸亮氨酸、异亮氨酸和缬氨酸。这3个基因中任何一个突变都会造成机体无法代谢上述氨基酸，这些氨基酸及其副产品在体内堆积，对大脑及身体器官造成损害。

BCKDHB基因编码BCKD多酶复合体（支链α-酮酸脱氢酶多酶复合体）的β亚基，2个α亚基和2个β亚基组成BCKD的一个E1单元。BCKDHB基因已发现40多种突变，多数于经典型枫糖尿症患者中发现，有点突变和小片段缺失，常见突变为R183P。

基因名称基因全名基因位置外显子个数 CDS长度
BCKDHB branched chain keto acid dehydrogenase E1, beta polypeptide 6q14.1 11 约3712 bp
基因摘要 This gene encodes the E1 beta subunit of branched-chain keto acid dehydrogenase, which is a multienzyme complex associated with the inner membrane of mitochondria. This enzyme complex functions in the catabolism of branched-chain amino acids. Mutations in this gene have been associated with maple syrup urine disease (MSUD), type 1B, a disease characterized by a maple syrup odor to the urine in addition to mental and physical retardation and feeding problems. Alternative splicing at this locus results in multiple transcript variants. [provided by RefSeq, Jan 2016].

基因 DBT 与疾病

BCKDHA, BCKDHB, DBT 这三个基因的表达产物结合成一个多酶复合体，代谢食物中的支链氨基酸亮氨酸、异亮氨酸和缬氨酸。这3个基因中任何一个突变都会造成机体无法代谢上述氨基酸，这些氨基酸及其副产品在体内堆积，对大脑及身体器官造成损害。

DBT基因编码BCKD多酶复合体（支链α-酮酸脱氢酶多酶复合体）的E2单元，已发现30多种突变，包括插入、缺失和点突变。

基因名称基因全名基因位置外显子个数 CDS长度
DBT dihydrolipoamide branched chain transacylase E2 1p31 11 约10815 bp
基因摘要 The branched-chain alpha-keto acid dehydrogenase complex (BCKD) is an inner-mitochondrial enzyme complex involved in the breakdown of the branched-chain amino acids isoleucine, leucine, and valine. The BCKD complex is thought to be composed of a core of 24 transacylase (E2) subunits, and associated decarboxylase (E1), dehydrogenase (E3), and regulatory subunits. This gene encodes the transacylase (E2) subunit. Mutations in this gene result in maple syrup urine disease, type 2. Alternatively spliced transcript variants have been described, but their biological validity has not been determined. [provided by RefSeq, Jul 2008].