“Olivia Farnsworth, an 8-year-old girl is the first unique case of chromosome 6p deletion. She can not feel pain, hunger, and the requirement of sleep. It is a congenital condition in which some part of chromosome 6 deletes during the process of cell division.”
A chromosome is a complex network of proteins and DNA. We, humans, have 46 chromosomes in 23 pairs, however, the structure and number of chromosomes vary among different organisms.
The chromosome has three distinct parts; centromere, arms, and telomeres. Each part performs a specific function, for instance, the telomere sequences help to maintain replication properly.
Likewise, the centromere helps chromosomes to arrange accurately during the process of replication, the two arms (“p” arm and “q” arm) have genetic information in the form of genes and the telomeres are the cap of the chromosomes that protects the genetic information.
Depending upon the location of the centromere the chromosomes are divided into several categories such as acrocentric, metacentric or submetacentric. Chromosome 6 is a medium submetacentric chromosome having the “p” arm slightly shorter than the “q” arm.
Take a look at the different forms of chromosome 6 depending upon its length:
Chromosome 6p deletion is a mutation in which chromosome 6 loses some part. The mutation causes various abnormalities; occur either at gene level or chromosome level.
Read our article on the present topic: Genetic Mutations- Definition, Types, Causes and Examples.
Common gene mutations are deletion, duplication, single nucleotide polymorphism and insertion while common chromosomal mutations are changing in chromosome number or structure.
Structural chromosomal anomalies cause a change in chromosome structure, on the other side, numerical abnormalities change the number of chromosomes of an organism. For instance, in the case of Down syndrome, an extra number of chromosome 21 is present.
Various types of numerical chromosomal anomalies are enlisted here,
The cry-do-cat syndrome is a type of structural aberration in which some portion of the “p” arm of chromosome 5 is deleted.
Similarly, 6p deletion is such a type of structural aberration that causes several congenital problems which are very rare throughout the world.
In the present article, I will explain one unique case of chromosome 6p deletion, the role of chromosome and its function.
Genetic information on chromosome 6
Chromosome 6 contains more than 1000 genes (~1200-1300 genes) with more than 170 million base pairs on it. The majority of the genes present on chromosome 6 are associated with the immune system, specifically, the genes for major histocompatibility complexes (HLA).
- Generation of Antibody Diversity
- Immunogenetics class 2: antibody diversity
- Immunogenetics class 3: T cell gene rearrangement
The major histocompatibility genes are HLA-A, HLA-B, HLA-C, HLA-DQA1, HLA-DQB1, HLA-DQ, HLA-DRA, HLA-DRB1, HLA-DRB3, HLA-DRB4, HLA-DRB5, HLA-DPA1, HLA- DPB1, HLA-Cw present on the “p” arm of chromosome 6. See the image below which shows the location of the HLA genes on the p arm of chromosome 6:
The total size of chromosome 6 is 170Mb in which the short “p” arm and longer “q” arm contains a 60Mb portion and a 110Mb portion of the total size, respectively.
Chromosome 6 is involved in some of the well-known diseases such as maple syrup urine disease, Parkinson’s disease, polycystic kidney disease and Rheumatoid arthritis.
Also, ring chromosome, del 6q, del 6q16, del 6p22 and insertion in the proximal end on the ‘p’ arm are some of the common types of structural chromosomal aberrations associated with chromosome 6. Now let us discuss specifically the 6p deletion.
Chromosome 6p Deletion:
An 8-year-old girl named Olivia Farnsworth is the first unique case of chromosome 6p deletion. The story of her came to light when she was hit by a car and injured badly. However, she had not felt pain, not even cried.
Once her condition was diagnosed, her mother admitted that she doesn’t need sleep or to eat. Furthermore, she confessed that she never feels danger, pain, hunger, and the need for sleep. She feels lesser emotions in comparison with other girls as well.
Doctors named her the first “Bionic girl” for her superhuman capability. Tons of articles are available on the Internet which covered the story of Olivia Farnsworth but none of the articles explained which part of chromosome 6 or how many genes from chromosome 6 are deleted.
The cytological analysis reveals that the major portion of the “p” arm was deleted from the single copy of chromosome 6 in Olivia’s case.
The major portion of chromosome 6 is associated with the components of the immunes system as we said. The immune system gives power to the organism to fight against infection or disease. We can feel pain when a signal to the brain is given from the site of a cut or damage.
Genes for the major histocompatibility complex are located on the p arm of chromosome 6. So hypothetically, it is possible that some of the genes from these “HLA genes clouds” may be deleted which gives insane power to Olivia.
Interestingly, other genes present on chromosome 6 are mainly associated with diabetes, developmental delay, distinctive facial features, intellectual disability and other mantle problems but not with hunger, pain or sleep.
standard cytogenetic practices show that the severity of the phenotype depends on the size of the deleted fragment, meaning the larger the deleted fragment, the more severe the condition is! Here, the condition is congenital and non-inherited.
Besides, 6p deletion, other 6p deletions are reported in CCD (CleidoCranial Dysplasia) del 6p12.3, deletion of 6p22, and terminal deletion of 6p arm. In all these deletions, the major phenotypic abnormalities are associated with developmental delay, mental retardation and intellectual disability but not with lack of sleep or huger.
Though more than 100 cases like Olivia are reported, she is the only person in the world who has all three phenotypes of “no pain, no sleep and no hunger”. Moreover, approximately, 3000 cases are reported worldwide in which chromosome 6 deletion is involved (but none of the cases is like Olivia).
Do you Know?
1 in every 200 children born with chromosomal abnormalities worldwide.
Is she superhuman?
Most people think so but she is not. It isn’t power, it’s her limitation.
Feel of pain and hunger are the first line of defense for a body. The pain is a signal for danger indicating that some portion of our body is damaged or not well. Also, hunger is a sign of the requirement for energy.
When we feel hungry, we eat. Suppose if we can not feel hunger, the carbohydrate, protein, and energy level of our body decreases and we can not feel it. We can be unconscious or died due to hunger. Imagine the condition in which we are injured badly and we don’t even know about it. What will happen?
Further, due to lack of sleep, the working efficiency of our brain decreases.
If we do not sleep for a long time, we can’t differentiate reality and illusion.”
So scientifically, it is not a superpower. Still, she is different from us. We can say that she is the “naturally genetically modified organism”. Nonetheless, the reason for less hunger and sleeplessness is not clear.
Interesting article: 20 Incredible DNA Facts: The 20th One Is Actually Shocking.
The chromosome 6p deletion case of Olivia is a unique and only case in the world.
I personally believe that mutation or any other alteration gives survival power to the organism and Olivia is an example of it. In the future, we can hope that Non-oxygen dependent GMOs can be created. And, that will change the fate of the human race.