Homocystinuria（高胱氨酸尿症）

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检测编号：NA0180005


基因 CBS 与疾病

CBS基因表达产物胱硫醚合成酶能将高半胱氨酸转化为胱硫醚和甲硫氨酸。在依赖维生素B6的高半胱氨酸代谢过程中发挥重要作用，并且是包括甲硫氨酸在内的氨基酸合成途径关键酶。已发现150多种突变，最常见的是I278T和G307S。该酶活性丧失导致高半胱氨酸及其他副产物在血液和尿液中堆积，对机体造成损害。

基因名称基因全名基因位置外显子个数 CDS长度
CBS cystathionine-beta-synthase 21q22.3 17 约2590 bp
基因摘要 The protein encoded by this gene acts as a homotetramer to catalyze the conversion of homocysteine to cystathionine, the first step in the transsulfuration pathway. The encoded protein is allosterically activated by adenosyl-methionine and uses pyridoxal phosphate as a cofactor. Defects in this gene can cause cystathionine beta-synthase deficiency (CBSD), which can lead to homocystinuria. This gene is a major contributor to cellular hydrogen sulfide production. Multiple alternatively spliced transcript variants have been found for this gene. [provided by RefSeq, Feb 2016].

基因 MMADHC 与疾病

MTHFR, MTR, MTRR, 和 MMADHC 基因的表达产物在高半胱氨酸转化为甲硫氨酸的途径中起到辅助作用，这些基因突变也会导致本病的发生。

MMADHC编码产物将维生素B12转化成腺苷钴胺素或甲基钴胺素。腺苷钴胺素是甲基丙二酰辅酶A变位酶发挥功能的必需物质。已发现4种突变与高胱氨酸尿症有关。

基因名称基因全名基因位置外显子个数 CDS长度
MMADHC methylmalonic aciduria (cobalamin deficiency) cblD type, with homocystinuria 2q23.2 8 约1437 bp
基因摘要 This gene encodes a mitochondrial protein that is involved in an early step of vitamin B12 metabolism. Vitamin B12 (cobalamin) is essential for normal development and survival in humans. Mutations in this gene cause methylmalonic aciduria and homocystinuria type cblD (MMADHC), a disorder of cobalamin metabolism that is characterized by decreased levels of the coenzymes adenosylcobalamin and methylcobalamin. Pseudogenes have been identified on chromosomes 11 and X.[provided by RefSeq, Nov 2008].

基因 MTHFR 与疾病

MTHFR, MTR, MTRR, 和 MMADHC 基因的表达产物在高半胱氨酸转化为甲硫氨酸的途径中起到辅助作用，这些基因突变也会导致本病的发生。

MATHFR基因编码亚甲基四氢叶酸还原酶，在氨基酸代谢过程中起作用，并且在依赖叶酸的代谢途径中具有重要作用，另外，该酶将5,10-二甲基四氢叶酸转化成5-甲基四氢叶酸，这个过程在将高半胱氨酸转化成蛋氨酸的多级代谢途径中是必须的。已发现40多种突变与高半胱氨酸尿症有关。

基因名称基因全名基因位置外显子个数 CDS长度
MTHFR methylenetetrahydrofolate reductase (NAD(P)H) 1p36.3 12 约7150 bp
基因摘要 The protein encoded by this gene catalyzes the conversion of 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate, a co-substrate for homocysteine remethylation to methionine. Genetic variation in this gene influences susceptibility to occlusive vascular disease, neural tube defects, colon cancer and acute leukemia, and mutations in this gene are associated with methylenetetrahydrofolate reductase deficiency.[provided by RefSeq, Oct 2009].

基因 MTR 与疾病

MTHFR, MTR, MTRR, 和 MMADHC 基因的表达产物在高半胱氨酸转化为甲硫氨酸的途径中起到辅助作用，这些基因突变也会导致本病的发生。

MTR编码甲硫氨酸合成酶，需要在甲基钴胺素和甲硫氨酸合成酶还原酶（MTRR编码）共同存在时发挥作用，将高半胱氨酸转化为甲硫氨酸。已发现20多种突变与高半胱氨酸尿有关，大多导致甲硫氨酸合成酶功能丧失。

基因名称基因全名基因位置外显子个数 CDS长度
MTR 5-methyltetrahydrofolate-homocysteine methyltransferase 1q43 33 约10558 bp
基因摘要 This gene encodes the 5-methyltetrahydrofolate-homocysteine methyltransferase. This enzyme, also known as cobalamin-dependent methionine synthase, catalyzes the final step in methionine biosynthesis. Mutations in MTR have been identified as the underlying cause of methylcobalamin deficiency complementation group G. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq, May 2014].

基因 MTRR 与疾病

MTHFR, MTR, MTRR, 和 MMADHC 基因的表达产物在高半胱氨酸转化为甲硫氨酸的途径中起到辅助作用，这些基因突变也会导致本病的发生。

MTRR编码甲硫氨酸合成酶还原酶，在甲硫氨酸合成酶的作用过程中发挥作用，已发现20多种突变。

基因名称基因全名基因位置外显子个数 CDS长度
MTRR 5-methyltetrahydrofolate-homocysteine methyltransferase reductase 5p15.31 15 约3298 bp
基因摘要 This gene encodes a member of the ferredoxin-NADP(+) reductase (FNR) family of electron transferases. This protein functions in the synthesis of methionine by regenerating methionine synthase to a functional state. Because methionine synthesis requires methyl-group transfer by a folate donor, activity of the encoded enzyme is important for folate metabolism and cellular methylation. Mutations in this gene can cause homocystinuria-megaloblastic anemia, cbl E type. Alternative splicing of this gene results in multiple transcript variants. [provided by RefSeq, Dec 2015].