Pachyonychia Congenita

Pachyonychia congenita is a condition that primarily affects the skin and nails. The signs and symptoms of this condition usually become apparent within the first few years of life.

Other names for Pachyonychia Congenita #

• Congenital pachyonychia

• Jackson-Lawler syndrome (PC-2)

• Jadassohn-Lewandowski syndrome (PC-1)

• Pachyonychia congenita syndrome

Causes of Pachyonychia Congenita #

• Mutations in several genes, including KRT6A, KRT6B, KRT6C, KRT16, and KRT17, can cause pachyonychia congenita.

• All of these genes provide instructions for making tough, fibrous proteins called keratins.

• These proteins form networks that provide strength and resilience to the tissues that make up the skin, hair, and nails.

• When pachyonychia congenita is caused by mutations in the KRT6A gene, it is classified as PC-K6a.

• Similarly, KRT6B gene mutations cause PC-K6b, KRT6C gene mutations cause PC-K6c, KRT16 gene mutations cause PC-K16, and KRT17 gene mutations cause PC-K17.

Symptoms of Pachyonychia Congenita #

Pachyonychia congenita (PC) is characterized by

• Hypertrophic nail dystrophy

• Painful palmoplantar keratoderma and blistering

• Oral leukokeratosis

• Pilosebaceous cysts (including steatocystoma and vellus hair cysts)

• Palmoplantar hyperhydrosis

• Follicular keratoses on the trunk and extremities.

Diagnosis of Pachyonychia Congenita #

Pachyonychia congenita is diagnosed by clinical findings and/or by the identification of a heterozygous pathogenic variant in one of the five keratin genes known to cause PC: KRT6A, KRT6B, KRT6C, KRT16, and KRT17.

Treatment of Pachyonychia Congenita #

• Pain from the palmoplantar keratoderma may be reduced somewhat by limiting friction and trauma to the feet by minimizing walking or standing, reducing hydration of the stratum corneum by using wicking socks and ventilated footwear, selecting comfortable shoes, and maintaining ideal body weight.

• Foot care includes paring down of hyperkeratotic areas and topical therapies for hyperkeratosis (emollients and lotions containing keratolyics).

• Care of thickened nails often requires the use of surgical or razor blades or sanders such as a Dremel tool.

• Troublesome nails removed surgically frequently grow back in some form.

• Good oral hygiene and brushing gently with a soft toothbrush can improve thick, white patches on the tongue and oral mucosa.

• Secondary fungal and bacterial infections that require treatment are common, cysts usually do not require treatment but can be incised and drained if infected or painful.

• Bottle-fed infants with leukokeratosis may need a soft nipple with an enlarged opening. Rarely, young children with laryngeal thickening/growths need emergency surgery to reestablish the airway however, surgery may exacerbate the condition.