Expert Reviewed By: Dr. Brandon Colby MD
Adenine phosphoribosyltransferase (APRT) deficiency is a rare genetic disorder characterized by the accumulation of a compound called 2,8-dihydroxyadenine (DHA) in the body, leading to kidney stones and kidney damage. There are two types of APRT deficiency - Type I and Type II. The Japanese type, also known as Type I, is more prevalent among Japanese individuals. In this article, we delve into understanding, diagnosing, and using genetic testing for APRT deficiency, Japanese type.
Understanding APRT Deficiency, Japanese Type
APRT deficiency occurs due to mutations in the APRT gene, which is responsible for producing an enzyme called adenine phosphoribosyltransferase. This enzyme plays a crucial role in purine metabolism, a process that breaks down purines, the building blocks of DNA, RNA, and energy molecules like ATP. In individuals with APRT deficiency, the lack of functional enzyme leads to the accumulation of DHA, causing kidney stones and kidney damage.
According to a study analyzing a mutant allele common to type I APRT deficiency in Japanese subjects, two nucleotide substitutions in affected alleles were identified. This mutation is more common in Japanese individuals, hence the term "Japanese type." Another article differentiates between type I and type II deficiencies in Japanese patients, providing further insight into the purine metabolism of this disorder.
Moreover, a study provides evidence for a common ancestor disease-causing gene for Japanese-type APRT deficiency, explaining its expansion among Japanese. This information is vital in understanding the genetic basis of the disorder and how it may affect certain populations.
Diagnosing APRT Deficiency, Japanese Type
Diagnosing APRT deficiency involves a combination of clinical examination, laboratory tests, and genetic testing. Clinical examination may reveal kidney stones or kidney damage, while laboratory tests can detect elevated levels of DHA in the urine. However, genetic testing is essential for confirming the diagnosis and differentiating between type I and type II deficiencies.
Uses of Genetic Testing for APRT Deficiency
Genetic testing can be beneficial in various ways for individuals with APRT deficiency, Japanese type:
- Confirming the diagnosis: Genetic testing can identify the specific mutations in the APRT gene, confirming the diagnosis of APRT deficiency and distinguishing between type I and type II.
- Carrier testing: Family members of affected individuals can undergo genetic testing to determine if they carry the mutated gene. This information can be useful for family planning and understanding the risk of passing the disorder to future generations.
- Prenatal testing: Couples with a family history of APRT deficiency can opt for prenatal testing to determine if their unborn child is affected by the disorder. This can help them make informed decisions about their pregnancy and prepare for the potential care of an affected child.
- Newborn screening: Although not routinely performed, newborn screening for APRT deficiency can help identify affected infants early in life, allowing for prompt treatment and management of the disorder.
In conclusion, understanding, diagnosing, and using genetic testing for APRT deficiency, Japanese type, is essential for the accurate identification and management of this rare genetic disorder. Genetic testing can help confirm the diagnosis, identify carriers, and provide prenatal testing options for affected families. By increasing awareness and knowledge about this disorder, we can work towards improving the lives of those affected and their families.
About The Expert Reviewer
Dr. Brandon Colby MD is a US physician specializing in the personalized prevention of disease through the use of genomic technologies. He’s an expert in genetic testing, genetic analysis, and precision medicine. Dr. Colby is also the Founder of and the author of Outsmart Your Genes.
Dr. Colby holds an MD from the Mount Sinai School of Medicine, an MBA from Stanford University’s Graduate School of Business, and a degree in Genetics with Honors from the University of Michigan. He is an Affiliate Specialist of the American College of Medical Genetics and Genomics (ACMG), an Associate of the American College of Preventive Medicine (ACPM), and a member of the National Society of Genetic Counselors (NSGC)