Seeing the "anonychia" hand reminded me of Voldemort's nose...

What do you think of when you think of people without fingerprints?

The perverted criminal in the movie who peels off the skin on his fingers to cover up his crime?

In the movie "Seven Deadly Sins", the perverted murderer peeled off his fingerprints in advance to cover up the traces of the crime. Image source: "Seven Deadly Sins"

It hurts to think about actively peeling off fingerprints, but there are indeed cases in life where fingerprints are damaged. For example, the fingerprints of patients with severe burns on their fingers are likely to be damaged. For another example, the fingerprints of miners working underground in mines are often worn out.

But these are all caused by external factors. Are there people who are born without fingerprints?

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Born without fingerprints

It is true that people are born without fingerprints. As you can probably guess, this is a genetic defect, a problem with the genes.

Fingerprints can wear off, but it's very rare for them to be completely absent. Image credit: hippopx

At present, there are two main typical diseases that cause people to be congenitally without fingerprints. One is called reticular pigmented dermatosis and the other is called Nalgary syndrome. We will introduce them one by one.

Reticular pigmented dermatosis

Dermatopathia pigmentosa reticularis (DPR) is a rare disease, and one of the rarest (there are only a few papers describing it). It is also known as “delayed immigration syndrome,” which vividly summarizes the plight of patients—it is difficult to go through immigration procedures without fingerprints.

The patient's fingerprints are missing and the lines on his palms are also reduced. Image source: Reference [1]

The condition of reticular pigmented dermatosis can be mild or severe. Some patients have no other obvious discomfort except for the loss of fingerprints. However, some patients show a series of symptoms, including thin hair, brittle nails, reticular pigmentation of the skin, hyperkeratosis of the skin (palms and soles), blisters, less sweating or more sweating, etc.

Pigmentation appears on the patient's back. Image source: Reference [2]

In fact, researchers do not know much about this disease so far. They only know that it is a rare autosomal dominant genetic disease. The problematic gene is the keratin 14 gene located on the long arm of chromosome 7. Mutations (nonsense mutations or frameshift mutations) cause the gene to completely lose its function, leading to the occurrence of the disease (when missense mutations occur, it may cause epidermolysis bullosa).

Is this disease curable? Unfortunately, as a genetic disease whose cause is not fully understood, reticular dermatosis pigmentosa cannot be cured.

In fact, even diagnosing this disease requires genetic testing, and it is currently difficult to regrow missing fingerprints.

However, symptoms such as skin hyperkeratosis and blisters can be treated with topical medications (such as steroids) or cold compresses to control the progression of the disease.

Nalgiri syndrome

Similar to reticular dermatosis pigmentosa, Naegeli-Franceschetti-Jadassohn syndrome (NFJS) is also a genetic disease that can cause the loss of fingerprints.

Moreover, the cause of Nalgiri syndrome is similar to that of reticular dermatosis pigmentosa, which is also a problem with the keratin 14 gene , so some scholars argue that these two diseases can be classified as one.

The patient's fingerprints are missing and his fingers are deformed. Image source: Reference [3]

However, the symptoms of the two are indeed different. In addition to showing symptoms similar to reticular pigmented dermatosis, such as fingerprint loss, reticular pigmentation of the skin, and hypofunction of sweat glands, patients with Nalgary syndrome also have a typical symptom, which is a series of problems with their teeth, mainly including yellowing of teeth, abnormal tooth arrangement, and enamel defects.

The patient's teeth are yellow. Image source: Reference [4]

In addition, many patients have obvious reticular pigmentation on their tongues. Sometimes, the patient's finger joints also become abnormal, showing spindle-shaped swelling (i.e., joint hyperplasia appears spindle-shaped).

The patient's tongue showed obvious reticular pigmentation. Image source: Reference [4]

In most cases, the clinical symptoms of Nalgiri syndrome are very typical and can be diagnosed based on clinical symptoms. Of course, genetic testing can also be used to confirm the diagnosis if necessary.

Similar to reticular dermatosis pigmentosa, Nalgiri syndrome is also a rare disease . Researchers currently know little about it, and there is no good treatment plan other than symptomatic treatment.

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Even worse than no fingerprints is no fingernails

Not having fingerprints is sensational enough, but some people have even more special situations. They have no nails. It's not because of injury or infection of onychomycosis that the nails are removed for treatment, but because they are born without nails.

Except for the big toe of the right foot, the patient has all toenails missing. Image source: Reference [5]

In this rare condition, called Anonychia congenita , one or more of the fingernails may be missing (or sometimes underdeveloped rather than absent) but the nail bed is normal.

The patient's toenails are underdeveloped. Image source: National Human Genome Research Institute

Research suggests that the cause of congenital aonychia is a mutation in the RSPO4 gene located on the short arm of chromosome 20. The RSPO4 gene encodes a protein called R-spondin-4, which is involved in signal transduction of the Wnt signaling pathway, which is involved in regulating the growth and development of nails in the early stages of embryonic development.

When the RSPO4 gene mutates, it will lead to a reduction in R-spondin-4 protein or loss of function, eventually causing the complete disappearance or incomplete development of the nails.

The patient's fingernails on both hands and toes are underdeveloped, but his bones are normally developed. Image source: Reference [6]

Congenital aonychia is an autosomal recessive trait , and the patient's parents are likely to be carriers of the gene mutation but will not show symptoms.

So far, there is no effective treatment for anonychia. However, if it is just nail loss, you are lucky, because RSPO4 gene mutation may cause hair abnormalities, deafness, mental retardation, bone problems, intellectual problems, etc. (related to the location of the mutation), and only a few patients have no other abnormalities except nail abnormalities.

Source @Cold Knowledge bot

The cases of no fingerprints and no nails introduced today have one thing in common, that is, they are extremely rare, and even among rare diseases, their incidence rate is extremely low.

Because it is so rare, there are almost no targeted treatments. Perhaps one day, gene therapy can bring hope of cure to these patients.

References

[1] Datta A, Gupta N, Pradhan S, Bandyopadhyay D. Dermatopathia Pigmentosa Reticularis. Indian J Dermatol. 2019 Mar-Apr;64(2):149-151.

[2] Shanker V, Gupta M. Dermatopathia pigmentosa reticularis: A rare reticulate pigmentary disorder. Indian Dermatol Online J. 2013 Jan;4(1):40-2.

[3] Sanodia G, Hulmani M, Kumar VJ. Naegeli-Franceschetti-Jadassohn Syndrome: A Rare Reticulate Pigmentary Disorder. Indian J Dermatol. 2019 May-Jun;64(3):235-238.

[4] Shah BJ, Jagati AK, Gupta NP, Dhamale SS. Naegeli-Franceschetti-Jadassohn syndrome: A rare case. Indian Dermatol Online J. 2015 Nov-Dec;6(6):403-6.

[5] Avhad G, Jerajani HR. Anonymchia congenita. Indian Dermatol Online J. 2012 May;3(2):156.

[6] Bin Nooh DM, Hegazi TM, Bukhari IA. Anonymchia congenita in different generations of a single Saudi family. Saudi Med J. 2020 Feb;41(2):195-198.

END

Review expert: Zhang Yuhong, Chief Physician of Dermatology, Zhengzhou Central Hospital Affiliated to Zhengzhou University

Tadpole Musical Notation original article, please indicate the source when reprinting

Editor/Heart and Paper