Anonychia: Absence of Fingernails and Toenails

Introduction

The absence of fingernails or toenails is known as anonychia. This anomaly can be caused by various factors. It includes self-inflicted trauma, congenital ectodermal defect, severe infection, ichthyosis, severe allergic contact dermatitis, lichen planus, Raynaud phenomenon, epidermolysis bullosa, or serious exfoliative diseases. The congenital form of anonychia is rare and usually occurs due to mutations.

What Is Anonychia?

Anonychia is a nail disorder that affects both the fingernails and toes. Individuals with this illness generally have no fingernails or toenails. This lack of nails is evident in some individuals from birth (congenital). In certain situations, only a portion of the nail (hyponychia) is gone, or not all fingers and toes are afflicted. All other tissues at the tips of the fingers and toes structures that generally support nail growth, such as the nail bed, are usually normal. Individuals with anonychia congenita usually do not have other health issues associated with the illness. However, anonychia may be seen as a symptom of other conditions.

What Are the Other Names for Anonychia?

• Aplastic nails.

• Absent nails.

• Hyponychia congenita.

• Congenital absence of nails.

What Are the Causes of Anonychia?

Congenital anonychia occurs due to a mutation in the RSPO4 gene and is a rare disorder that can manifest from birth. Because of the autosomal recessive nature of this mutation, a person must inherit a defective gene from both parents to be affected. The RSPO4 gene encodes a protein known as R-spondin-4. This gene participates in the Wnt signaling pathway, which regulates the development of cells and tissues.

Wnt signaling is required for cell adhesion, cell division, cell migration, and other cellular processes. Wnt signaling is important for nail growth and development during early development. Mutations in the RSPO4 gene result in synthesizing a protein with limited or no function. As a result, R-spondin-4 cannot take part in the Wnt signaling pathway, and nails form incorrectly or not at all.

Anonychia can develop as an acquired condition due to trauma, frostbite, medication responses, or circulatory insufficiency. Other probable reasons include severe infection, lichen planus, ichthyosis, and other diseases. Anonychia is also associated with syndromes that affect many regions of the body.

Other uncommon causes of anonychia are the following.

• Congenital ectodermal dysplasias.

• Coffin-siris syndrome.

• Ichthyosis.

• Surgical ablation.

• Self-inflicted trauma.

• Phenytoin exposure during pregnancy.

• Stevens-Johnson syndrome.

• Brachydactyly type B.

• Cooks syndrome.

• Infections.

• Nail-patella syndrome.

Is Anonychia an Inherited Condition?

Anonychia is not always an inherited condition. However, anonychia congenita is an inherited condition. This is in an autosomal recessive form. It means that both copies of the RSPO4 gene in each cell must be mutated to have anonychia. Thus the parents of a person with a congenital anonychia disorder carry one copy of the defective gene, although they usually do not have the condition.

What Is Anonychia Congenita?

Anonychia congenita is also known as isolated congenital anonychia, congenital nail absence, or autosomal recessive nonsyndromic congenital nail disorder type 4. It is an extremely rare genetic condition that affects the fingernails and toenails. Individuals with anonychia congenita often lack all of their fingernails and toenails. This lack of nails is seen from birth. In some instances, only a portion of the nail is absent (hyponychia), or not all fingers and toes are affected. All other tissues at the tips of the fingers and toes are normal.

What Are the Clinical Features of Anonychia?

The clinical symptoms of anonychia might vary depending on the etiology and severity of the disorder. However, several characteristics are shared by all.

It includes the following.

• The most noticeable symptom of anonychia is the lack of nails or fingernails, which may be present in one or more digits.

• When nails are absent, the skin on the fingertips may appear smooth and shiny.

• Individuals with anonychia may struggle with fine motor skills, such as holding small objects or working on a keyboard.

• The nail bed may be malformed or have aberrant growth patterns in some conditions.

• As the fingertips lack the protective covering of nails, they are more vulnerable to injury, such as cuts or bruising.

• Individuals with anonychia may be more susceptible to infections in the region affected.

How Is Anonychia Diagnosed?

Anonychia is diagnosed based on medical and family history and a thorough physical examination. X-rays of the individual's limb and foot usually reveal normal results. A molecular genetic test for the RSPO4 gene mutation can be done to diagnose anonychia congenita.

What Are the Treatment Options Available for Anonychia?

Treatment options for anonychia are decided by the cause and severity of the condition.

Commonly used treatment options are the following.

• Artificial Nails - Using prosthetic nails may help enhance the appearance of anonychia. Artificial nails can be attached with nail glue and adjusted according to the color and shape of the existing nails.

• Surgery - If anonychia is caused by a congenital abnormality or damage, surgical procedures may be considered. Surgical methods may include using a synthetic implant and grafting tissue from the patient's body to the nail bed.

• Medications - If anonychia occurs because of an underlying medical illness, medications to address the underlying condition may be administered.

• Lifestyle Modifications - People with anonychia must adequately care for their skin and nails. This includes avoiding harsh chemicals, keeping the nail area clean and dry, and using protective gloves while handling chemicals.

Conclusion

Anonychia is a condition in which a person's nails on their fingers or toes are missing. The treatment options for anonychia are determined by the underlying cause and severity. As anonychia is a rare condition, discussing the treatment options with a doctor who can assess the patient's situation and suggest the best course of action is essential.