Which gene causes thalassemia

Genetic analysis revealed 15 kinds of mutations and 30 genotypes, including The distributions of mutations and hematological features are shown in Table 3. In the present study, we have investigated the prevalence and mutation characteristics of thalassemia among the children in Yunnan province, the southwestern of China. Compared with the overall prevalence, the higher thalassemia prevalence in Yunnan province showed in our study.

The reason may be concerned to the selection of the subjects who detected thalassemia gene mainly due to microcytic hypochromic anemia, hemolytic anemia of unknown origin, not random crowd, which is also the limitation of this study. This result is different to the other southern regions in China However, CD41—42 is the most frequent mutation in Guangxi and Hainan in the southern of China 17 , The difference was probably due to the difference of samples and subjects.

Additionally, two rare mutations of CD34 and Int were identified in the children according to our knowledge Table 2 , which was the first report of the abnormal hemoglobin in the Chinese population. Yunnan is a multi-ethnic province, thus the heterogeneity were caused by population admixture, marriage patterns, and migrations.

Our data suggested that the prevalence and gene mutation spectrum of thalassemia display obviously heterogeneity among children in Yunnan Province. The findings extended the mutation spectrum of thalassemia in this region, which provided the valuable information for premarital and pre-pregnancy screening, prenatal diagnostic services, and designing appropriate prevention programs to control the incidence of severe thalassemia for future in this area.

The studies involving human participants were reviewed and approved by The Kunming Children's Hospital research ethics committee. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. This work was supported by the National Natural Science Foundation of China grant no: ; the Medical reserve talents training plan of Yunnan Health and Family Planning Commission grant no: H , and the Medical and health science and technology plan of Kunming Health and Family Planning Commission grant no: , and the Kunming science and technology plan project grant no: S , and the 17th batch of training plan for young and middle-aged academic and technical leaders and reserve candidates in Kunming.

Ann Hum Genet. Study on the characteristics of major birth defects in 1. The thalassemias are a group of recessively inherited conditions. Recall that genes come in pairs. In recessive conditions, both members of the pair associated with the condition must be changed, or mutated. This is different from a dominant condition, in which only one copy of the gene need be changed in order to manifest symptoms. In recessive conditions, a benign trait or carrier state can exist in which an individual has both a normal and a mutated copy of the gene.

The term "normal" is a convention to simply describe the copy of the gene, called an allele, that is seen most often in the general population. The normal allele is able to compensate for the missing or altered function of the mutant allele.

The different types of alpha thalassemia result from the loss of some or all of these alleles. Hb Bart syndrome, the most severe form of alpha thalassemia, results from the loss of all four alpha-globin alleles.

HbH disease is caused by a loss of three of the four alpha-globin alleles. In these two conditions, a shortage of alpha-globin prevents cells from making normal hemoglobin.

These abnormal hemoglobin molecules cannot effectively carry oxygen to the body's tissues. The substitution of Hb Bart or HbH for normal hemoglobin causes anemia and the other serious health problems associated with alpha thalassemia.

Two additional variants of alpha thalassemia are related to a reduced amount of alpha-globin. Because cells still produce some normal hemoglobin, these variants tend to cause few or no health problems.

A loss of two of the four alpha-globin alleles results in alpha thalassemia trait. People with alpha thalassemia trait may have unusually small, pale red blood cells and mild anemia. A loss of one alpha-globin allele is found in alpha thalassemia silent carriers. These individuals typically have no thalassemia-related signs or symptoms. The inheritance of alpha thalassemia is complex. Each person inherits two alpha-globin alleles from each parent.

If both parents are missing at least one alpha-globin allele, their children are at risk of having Hb Bart syndrome, HbH disease, or alpha thalassemia trait.

Symptoms Symptoms. The signs and symptoms vary depending on the severity of the thalassemia. For example, people affected by milder forms of thalassemia can develop mild anemia or may have no signs or symptoms of the condition at all. In addition to the signs and symptoms seen in intermediate thalassemia, people with severe forms of thalassemia may also experience severe anemia, poor appetite, paleness, dark urine, yellow discoloration of skin jaundice , and enlarged liver or heart.

Do you have updated information on this disease? We want to hear from you. Cause Cause. There are two main types of thalassemia, alpha thalassemia and beta thalassemia , which each affect a different part of hemoglobin the protein in red blood cells that carries oxygen.

Hemoglobin is made up of two different components subunits : beta globin and alpha globin. Each person has two copies of each of these genes, one inherited from the mother and one from the father. Changes mutations in the HBB gene lead to reduced levels of beta globin and cause beta thalassemia. Inheritance Inheritance. In general, thalassemia is inherited in an autosomal recessive manner; however, the inheritance can be quite complex as multiple genes can influence the production of hemoglobin.

The parents of an affected person usually each carry one mutated copy of the gene and are referred to as carriers. Carriers typically do not show signs or symptoms of the condition; although some carriers of beta thalassemia develop mild anemia.

For each gene, one copy is inherited from the mother and one is inherited from the father. If each parent is missing at least one gene copy, their children are at risk for having alpha thalassemia. However, the exact risk and the severity of each child's condition depends on how many gene copies are lost deleted and which combination of the HBA1 and HBA2 genes are affected.

Diagnosis Diagnosis. It has additional information on genetic testing for alpha thalassemia and beta thalassemia. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional. Treatment Treatment. The best treatment options depend on the severity of thalassemia. Prognosis Prognosis.

The long-term outlook prognosis for people with thalassemia depends on the type and severity of the condition. For example, severe thalassemia can cause early death due to heart failure, while less severe forms of thalassemia often do not shorten lifespan.