In this video we will be digging deeper into kidney dysplasia
Kidney dysplasia is also known as renal dysplasia
Renal meaning kidney Dys meaning not working properly
Plasia to do with development
In the simplest terms, kidney dysplasia is a developmental condition that occurs during early kidney development of the fetus resulting in abnormal kidneys.
Essentially, the internal structures of one or both of the fetus's kidneys
do not develop normally while in the mothers womb.
Most of us have two kidneys, which are at the back of either side of our spine.
Kidneys are bean shaped organs and are responsible for removing
waste from a person's blood in the form of urine and
also maintain a healthy balance of water, salts, and minerals
such as sodium, calcium, phosphorus, and potassium—in your blood
During normal development of a fetus, two thin tubes of muscles known as ureters,
which are long tubes that carry urine from the kidney to the bladder,
grow into the kidneys and branch out to create a network of tiny tube structures known as tubules.
These tubules collect the urine while the fetus grows and are responsible for returning nutrients, fluids,
and other substances that have been filtered from the blood, back to the blood if the body needs it.
In kidney dysplasia, the tubules do not branch out completely and so the urine that would normally
flow through the tubules has nowhere to go and so the urine collects in the affected kidneys.
This excess urine creates fluid-filled sacs called cysts which replace normal kidney tissue, affecting the normal development
of kidney tissue and eventually prevents the kidney from functioning properly. As a result, kidney function can deteriorate before or after birth.
Now, kidney dysplasia can either be unilateral or bilateral
and an affected kidney is called a dysplastic kidney.
Unilateral kidney dysplasia is when only one kidney is affected and will not work properly.
This type of dysplasia is usually less severe, as you can function normally with just one kidney.
As long as one kidney develops normally, most children don’t experience any serious symptoms.
Although, close monitoring of the one functioning kidney is warranted given the high stakes.
In some cases, the other non-affected kidney grows larger than normal
to make up for the dysplastic kidney and may be at risk for urinary tract infections or high blood pressure later in life.
Bilateral kidney dysplasia is when both kidneys are affected.
Since both kidneys are dysplastic in this case, it is much more serious and if severe enough
can be fatal to the developing fetus. In children, some may go on to develop kidney failure.
When this happens, the person affected is usually a baby or a young child, but it is more likely
to occur later in life, especially during puberty when the child's body grows quickly.
Kidney dysplasia is a common condition and estimates of incidence show that it occurs in about 1 in 4000 live births worldwide
Let's move on to how it is caused. First we will talk about the genetics behind kidney dysplasia.
Most of the cases of kidney dysplasia are sporadic. Meaning, the disease occurs infrequently
and irregularly and in a random or isolated manner as a result of genetic mutations.
This is known as a spontaneous fault or a spontaneous genetic mutation. Essentially, it is the permanent alteration in the DNA sequence that makes up a gene.
The gene affected in kidney dysplasia is ITGA8. This gene is key to cell structure and signalling of gene FGF20,
which is responsible for growth and development of the kidney.
When there is a mutation in gene ITGA8, signalling to gene FGF20 is altered,
and therefore so is kidney development, leading to irregular development of the kidneys.
Also, studies have shown that the over expression of β-Catenin during the development of kidneys in a fetus can lead to kidney dysplasia.
β-Catenin p lays a key role in kidney development as it is involved in cell to cell interactions,
signalling and regulation of copying gene sequences. In normal development,
β-Catenin controls genetic programs that are essential for the control of ureter and tubule branching in the kidneys.
In human dysplastic kidneys, this molecule is over-expressed leading to disorganized branching suggesting a role in the development of kidney dysplasia.
Although it is not common, kidney dysplasia can be inherited from our mother or father
as sometimes the mutated gene can be passed along from the parents to the fetus.
Kidney dysplasia can be either autosomal dominant or autosomal recessive.
When a disease is autosomal dominant, this means that the disorders can be inherited by a faulty
gene from only one parent who has the disease. This means that the child has a 50% chance of inheriting the defective gene.
When a disease is autosomal recessive, this means that the faulty gene is passed onto the offspring by both parents. The parents may not have the disease,
however, they may be carriers for the faulty gene and therefore pass it along.
In this case, the offspring has a 25% chance in developing the disease, and a 50% chance in being a carrier for the gene.
Some genetic syndromes can also be associated with the development and lead to kidney dysplasia and often depends on the person's other development abnormalities.
The syndromes associated include noonan's syndrome, denys-drash syndrome, turner syndrome and beckwith-wiedemann syndrome.
There are also some other, non-genetic, causes of kidney dysplasia such as the use of certain prescription or illegal drugs during pregnancy.
Kidney dysplasia has been associated with the use of seizure medications,
high blood pressure medications, and cocaine during pregnancy. The exact mechanism through
which seizure medication induces renal dysplasia is currently unknown,
however there are several hypotheses as to why this may occur.
The use of seizure medications during pregnancy can increase the risk of renal dysplasia from 1-2% to 4-9%.
ACE inhibitors, which is a high blood pressure medication, can also cause kidney dysplasia among other birth defects.
Using cocaine during pregnancy can impede fetal development and lead to kidney dysplasia among other defects due to it’s vasoconstrictive effects.
The developing fetus relies on a network of vessels to obtain the nutrients required for growth.
Cocaine causes constriction of these vessels, in turn disrupting the network, and disabling
the fetus from obtaining the nutrients it requires to develop normally.
When we talk about diagnosis of kidney dysplasia, there is a single main method, which is the use of ultrasounds.
During a womans pregnancy, this ultrasound is known a fetal sonogram.
Using this method, kidney dysplasia may be picked up before birth on the 20th week ultrasound scan pregnant women undergo.
If not picked up before birth, ultrasounds performed after birth can also diagnose kidney dysplasia in newborns.
Sometimes, kidney dysplasia may be picked up when the child is older which is usually found
during a scan that a child is having for another reason, such as after a urinary tract infection
or while undergoing other medical tests. It is also possible that individuals can go their entire lives undiagnosed.
This mainly happens when kidney dysplasia occurs in one kidney, and produces limited symptoms in the individual.