Alkaptonuria is a rare inherited disorder. This enzyme is used to break down a toxic substance called homogentisic acid. The buildup of homogentisic acid causes your bones and cartilage to become discolored and brittle.
He shared his thoughts and ideas on the subject in his celebrated Croonian Lectures held at the Royal College of Physicians in These genes are made up of a chemical called DNA deoxyribonucleic acidwhich is present in the form of double strands with rungs, much like a ladder.
But the only difference is that unlike a ladder, the DNA molecule is twisted into a helix. Once transferred to the offspring, the properties Alkaptonuria the black urine disease these genes are said to be inherited.
These genes are responsible for producing all the proteins in the cells that carry out a multitude of functions. This is the basis of human inheritance. A mutated gene is said to be defective as it produces a defective protein that cannot perform its normal function.
In this disease, the body cannot properly metabolize phenylalanine and tyrosine, which are two of the 20 amino acids building blocks of proteins leading to accumulation of homogentisic acid, one of the by-products of their metabolism.
Alkaptonuria is inherited as an autosomal recessive trait characteristic. Recessive genetic disorders occur when a person inherits the same abnormal gene for the same trait from both the parents.
This means that in order to get the disease, both the parents must have a copy of the defective gene, which in this case is the HGD gene. Thus, both parents will be carriers of the gene but do not suffer from the condition.
Epidemiology of Alkaptonuria The prevalence of alkaptonuria in most populations varies between 1 into 1 inpeople. However, in certain countries such as Slovakia, the Dominican Republic and Germany, its incidence is much higher.
For example, in Slovakia the incidence is as high as 1 in 19, people. Scientists have found that the underlying reason for this higher incidence is due to occurrence of up to 12 mutations simultaneously in the HGD gene, instead for the usual single mutation.
What are the Causes of Alkaptonuria? This enzyme helps breakdown the amino acids phenylalanine and tyrosine, which are important building blocks of proteins.
Mutations in the HGD gene produce a defective HGD enzyme, which hampers its role in the breakdown of phenylalanine and tyrosine. This results in the accumulation of HGA, which is an intermediate product of phenylalanine and tyrosine metabolism.
From early childhood, this acid is excreted in the urine, which has a characteristic black color. Homogentisic acid slowly accumulates in the connective tissues, which causes darkening of the skin and cartilage. Over time, usually after reaching adulthood, the affected tissues can become blue-black in color.
Moreover, a build-up of HGA in the joints leads to osteoarthritis. What are the Symptoms and Signs of Alkaptonuria? There are several symptoms and signs of alkaptonuria, which are briefly highlighted below: Urine becomes black in color upon exposure to air. Sweat and earwax can also exhibit a black color.
This occurs due to deposition of HGA in the connective tissues, especially cartilages.
Renal system - Human excretion: The kidney has evolved so as to enable humans to exist on land where water and salts must be conserved, wastes excreted in concentrated form, and the blood and the tissue fluids strictly regulated as to volume, chemical composition, and osmotic pressure. Under the drive of arterial pressure, water and salts are filtered from the blood through the capillaries of. I remember the day of March 19, very well. That was the last day I ever went jogging. That was the last day I could have hopped on my bike and ridden 50 miles if I wanted to. That was the last day I ate my favorite breakfast of a 3-egg omelet topped with cheese and veggies, with 3 pieces of. Jul 12, · The hallmark of the disease is passage of urine that becomes black when left standing. Garrod identified a familial pattern of inheritance and concluded that an inherited biochemical abnormality must result in the .
The cartilage of the ear lobes can become thickened, irregular and blue, grey or black in color. Dark spots can also occur on the sclera whites of the eyes.
The tendons can become thickened, inflamed and painful, technically termed as tendinitis. The thickened Achilles tendon is especially prone to tearing or rupturing.
Eventually, discoloration of the tendons can become visible on the overlying skin. Men with alkaptonuria may also develop prostate stones. Passage of these black stones can be extremely painful.
There can be chronic joint pain and inflammation arthritis. When the spine and large joints such as the hips and knees are affected, it is technically termed as ochronotic arthropathy.
Intervertebral discs can flatten, calcify and eventually fuse. This can result in ankylosis, a condition where the affected joints become stiff and immobile. Moreover, kyphosis or hunchback may occur, where there is an excessive convex curvature of the spine. Stiffening of Heart Valves:The RARE List™ is comprised of approximately 7, different rare diseases and disorders affecting more than million people worldwide.
More RARE Facts™ can be found here. We are often asked why some common diseases are included on the RARE List™. The answer is two fold:This is a list of rare diseases defined in the United States where a prevalence of less than , cases is the.
Mar 18, · Alkaptonuria is an inherited condition that causes urine to turn black when exposed to air.
The three major features of alkaptonuria are the presence of dark urine, ochronosis, a buildup of dark pigment in connective tissues such as cartilage and skin, and arthritis of the spine and larger joints.
Chapter 1 / Urinalysis 3 per day (and on average 1, mg of creatinine per day). Thus, the normal urine albumin to creatinine ratio (UACR) is urine .
Alkaptonuria is an autosomal recessive metabolic disorder characterized by accumulation of homogentisic acid, leading to darkened urine, pigmentation of connective tissue (ochronosis), joint and spine arthritis, and destruction of the cardiac valves (summary by Vilboux et al., )..
Alkaptonuria enjoys the historic distinction of being one of the first conditions in which mendelian recessive. Jul 12, · The hallmark of the disease is passage of urine that becomes black when left standing.
Garrod identified a familial pattern of inheritance and concluded that an inherited biochemical abnormality must result in the . Heredity - Universality of Mendel’s laws: Although Mendel experimented with varieties of peas, his laws have been shown to apply to the inheritance of many kinds of characters in almost all organisms.
In Mendelian inheritance was demonstrated in poultry (by English geneticists William Bateson and Reginald Punnett) and in mice. The following year, albinism became the first human trait.