Genetics
The causes of obesity are many, but there is little doubt that
genetic factors play an important role in its etiology. Humans
carry probably dozens of genes that are directly related to
body size. One of the specific roles for genes is the determination
of set points. Identification of such genes is important,
and several types of studies must be performed to address
this. Linkage analysis can be used to find physical locations
of genes that are relevant to a phenotype. If a specific gene
plays a role in the determination of a given phenotype, the
gene and the phenotype will be transmitted together (cosegregate)
across generations. The fact that the etiology of
obesity is so complex underscores the need for better understanding
of genetic determinants as a basis for more rational
interventions to treat obesity.
Several approaches have been used to search for specific
genes involved in obesity: identification of mutations responsible
for obesity in rodent models, association or linkage of
obesity measures with candidate genes in humans, and
chromosomal localization of genes by linkage of polymorphic
markers to obesity and related phenotypes in humans
and mice. To date, causative genes have been found for 5
obese mouse models. Two, leptin and leptin receptor,have been linked with variation in body fat in some human studies,
but, for leptin, causation has been shown only in 2 obese
children with homozygous missense mutations in the leptin
gene. Linkages or associations with body fat measures have
been reported for .20 other candidate genes in humans, but
relationships involving these genes were generally not strong
and in some cases were inconsistent among studies. Chromosomal
sites of genes responsible for several rare familial
human obesity syndromes have been identified, but none to
date have been linked to obesity in the general population. On
the other hand, with genome-wide searches, quantitative trait
linkages of body fat indexes have been reported for several
genetic markers in both humans and mouse models. Although
multiple genetic influences on obesity phenotypes are suggested
by these studies, in most cases the responsible gene
variants, their pathophysiological effects, and their interactions
with other genes and environmental factors remain to be
determined.
GeneticsThe causes of obesity are many, but there is little doubt thatgenetic factors play an important role in its etiology. Humanscarry probably dozens of genes that are directly related tobody size. One of the specific roles for genes is the determinationof set points. Identification of such genes is important,and several types of studies must be performed to addressthis. Linkage analysis can be used to find physical locationsof genes that are relevant to a phenotype. If a specific geneplays a role in the determination of a given phenotype, thegene and the phenotype will be transmitted together (cosegregate)across generations. The fact that the etiology ofobesity is so complex underscores the need for better understandingof genetic determinants as a basis for more rationalinterventions to treat obesity.Several approaches have been used to search for specificgenes involved in obesity: identification of mutations responsiblefor obesity in rodent models, association or linkage ofobesity measures with candidate genes in humans, andchromosomal localization of genes by linkage of polymorphicmarkers to obesity and related phenotypes in humansand mice. To date, causative genes have been found for 5obese mouse models. Two, leptin and leptin receptor,have been linked with variation in body fat in some human studies,but, for leptin, causation has been shown only in 2 obesechildren with homozygous missense mutations in the leptinยีน มีความเชื่อมโยงหรือความสัมพันธ์กับวัดไขมันของร่างกายการรายงานสำหรับอื่น ๆ ยีนที่ให้ผู้สมัคร.20 ในมนุษย์ แต่ความสัมพันธ์ที่เกี่ยวข้องกับยีนเหล่านี้ได้โดยทั่วไปไม่แข็งแรงและในบางกรณีไม่สอดคล้องกันระหว่างการศึกษา ของโครโมโซมไซต์ของยีนหลายหายากภาวะโรคอ้วนมนุษย์แสงศตวรรษได้รับการระบุ แต่ไม่มีการวันมีการเชื่อมโยงกับโรคอ้วนในประชากรทั่วไป บนอีก กับการค้นหาทั้งจีโนม ติดเชิงปริมาณรายงานการเชื่อมโยงดัชนีไขมันของร่างกายเครื่องหมายพันธุในมนุษย์และรูปแบบเมาส์ ถึงแม้ว่ามีการแนะนำหลายอิทธิพลทางพันธุกรรมในโรคอ้วนฟีโดยการศึกษานี้ ส่วนใหญ่กรณียีนรับผิดชอบตัวแปร ผล pathophysiological ของพวกเขา และการโต้ตอบกับยีนและปัจจัยแวดล้อมอื่น ๆ ยังคง เป็นกำหนด
การแปล กรุณารอสักครู่..