What are the other Names for this Condition? (Also known as/Synonyms)

• Alopecia Congenita with Keratosis Palmoplantaris
• Clouston Syndrome
• Keratosis Palmaris with Drumstick Fingers

What is Hidrotic Ectodermal Dysplasia 2? (Definition/Background Information)

• Hidrotic Ectodermal Dysplasia 2 (HED2) may be described as an uncommon form of hereditary diffuse palmoplantar keratoderma that is transmitted in an autosomal dominant manner. The condition manifests during childhood and is characterized by a triad of features that include palmoplantar keratoderma, nail abnormalities, and partial or complete hair loss
• Hereditary diffuse palmoplantar keratoderma is a type of palmoplantar keratoderma (PPK) caused by genetic mutations. PPK is a benign skin condition, wherein there is thickening of skin (keratoderma) of the palms and/or soles. PPK is considered to be a pattern of skin findings and not a condition in itself. The abnormal skin thickening can be focal (localized), widespread (diffused), or punctate type (appearing as tiny bumps)
• The signs and symptoms of Hidrotic Ectodermal Dysplasia 2 are progressive; however, an involvement of other body systems or organs is not noted. The treatment for the condition involves the use of moisturizers, hair care products, skin softeners, and systemic medications. The prognosis is determined on a case-by-case basis, but HED2 is a lifelong condition

Who gets Hidrotic Ectodermal Dysplasia 2? (Age and Sex Distribution)

• Hidrotic Ectodermal Dysplasia 2 is a rare congenital disorder. The presentation of symptoms may occur in childhood that progressively worsens with age
• Both males and females may be affected
• Worldwide, individuals of all racial and ethnic groups may be affected

What are the Risk Factors for Hidrotic Ectodermal Dysplasia 2? (Predisposing Factors)

• A positive family history may be an important risk factor, since Hidrotic Ectodermal Dysplasia 2 can be inherited
• Children born to consanguineous partners or spouses may have a high risk for the condition

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Hidrotic Ectodermal Dysplasia 2? (Etiology)

• Hidrotic Ectodermal Dysplasia 2 is caused by genetic abnormalities which are passed down (through families) in an autosomal dominant manner
• It is caused by mutations in the GJB6 gene (located at chromosome 13q) leading to the development of associated signs and symptoms

Ectodermal dysplasias are a group of hereditary genetic disorders involving the ectodermal tissues such as the skin (sweat glands), nails, hair, and teeth, resulting in mild or severe abnormalities.

Autosomal dominant: Autosomal dominant conditions are traits or disorders that are present when only one copy of the mutation is inherited on a non-sex chromosome. In these types of conditions, the individual has one normal copy and one mutant copy of the gene. The abnormal gene dominates, masking the effects of the correctly functioning gene. If an individual has an autosomal dominant condition, the chance of passing the abnormal gene on to their offspring is 50%. Children, who do not inherit the abnormal gene, will not develop the condition, or pass it on to their offspring.

What are the Signs and Symptoms of Hidrotic Ectodermal Dysplasia 2?

The signs and symptoms associated with Hidrotic Ectodermal Dysplasia 2 may vary widely from one individual to another (even within the same family members) and may include:

• Presence of brittle and sparse hair during infancy, which progresses to complete hair loss by puberty
• Children may have regular white nails, which then slowly worsens to become thick dystrophic (worn away) nails that get separated from the nail bed; the nails usually fall off
• Presence of abnormally-thickened skin on the palms of the hands and soles of the feet in children
• The skin thickening is progressive and involves the entire palm and sole (diffused); the knuckles, knees, and elbows are also affected
• Increased sweating
• Secondary infections, mostly of the feet, may take place
• Normal activities that involve the use of one’s hands and feet may be severely affected
• Increased skin pigmentation may be observed over the joints
• Clubbing of fingers is noted
• Teeth and gums are commonly not affected

How is Hidrotic Ectodermal Dysplasia 2 Diagnosed?

The diagnosis of Hidrotic Ectodermal Dysplasia 2 may involve the following tests and procedures:

• A complete evaluation of medical history along with a thorough examination of the skin lesions by a dermatologist
• The healthcare provider may also ask many questions related to the individual’s age, family medical history, current medications, cosmetics, body lotions used, other medical conditions, infections, etc.
• Blood tests that may include complete blood count (CBC) test, basic metabolic panel, and liver function test (LFT)
• Dermoscopy: It is a diagnostic tool where a dermatologist examines the skin using a special magnified lens
• Wood’s lamp examination: In this procedure, the healthcare provider examines the skin using ultraviolet light. It is performed to examine the change in skin pigmentation
• Molecular genetic testing to identify the gene involved
• Skin biopsy: A skin tissue biopsy is performed and sent to a laboratory for a pathological examination. The pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Hidrotic Ectodermal Dysplasia 2?

The complications of Hidrotic Ectodermal Dysplasia 2 may include:

• Emotional stress due to cosmetic concerns
• Disruption of normal life and activities if the condition is severe
• Social isolation
• Depression
• Reduced quality of life

Complications may occur with or without treatment, and in some cases, due to treatment also.

How is Hidrotic Ectodermal Dysplasia 2 Treated?

There is no cure for Hidrotic Ectodermal Dysplasia 2. The condition is managed by treating the various symptoms that may involve the following measures.

• Use of moisturizing creams and lotions
• Use of oral and systemic retinoids
• Administration of keratolytics (medicine containing salicylic acid)
• Hair care products and wigs may be helpful in managing alopecia
• Phototherapy
• Surgical debridement (removal of thickened skin)

Regular follow up visits with the healthcare provider is important and recommended.

How can Hidrotic Ectodermal Dysplasia 2 be Prevented?

Currently, Hidrotic Ectodermal Dysplasia 2 is a genetic disorder that cannot be prevented. However, the following may be considered:

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• Active research is currently being performed to explore the possibilities for treatment and prevention of inherited genetic disorders

What is the Prognosis of Hidrotic Ectodermal Dysplasia 2? (Outcomes/Resolutions)

• The prognosis of Hidrotic Ectodermal Dysplasia 2 is dependent upon the severity of the signs and symptoms and associated complications, if any
• Individuals with mild conditions have better prognosis than those with severe symptoms and complications. Typically, the prognosis may be assessed on a case-by-case basis

Additional and Relevant Useful Information for Hidrotic Ectodermal Dysplasia 2:

Cleaning the skin too hard with strong chemicals or soaps may aggravate the skin condition. Care must be taken avoid strong soaps and chemicals that could potentially worsen the condition.