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

• Keratosis Palmoplantaris with Corneal Dystrophy
• Oculocutaneous Tyrosinemia
• Tyrosinemia Type II

What is Richner-Hanhart Syndrome? (Definition/Background Information)

• Richner-Hanhart Syndrome is a form of hereditary focal palmoplantar keratoderma that is transmitted in an autosomal recessive manner. The condition manifests during early infancy
• Hereditary focal 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)
• Richner-Hanhart Syndrome, also known as Tyrosinemia Type II, is a metabolic disorder occurring due to deficiency in the enzyme tyrosinemia. This results in corneal dystrophy due to eye ulcers and mental retardation, apart from the skin symptoms (palmoplantar keratoderma)
• A diagnosis of Richner-Hanhart Syndrome can be made via skin exams, eye exams, and various other diagnostic tools. A management of the condition primarily involves dietary control (low tyrosine and low phenylalanine) and treating the skin and eye symptoms. The prognosis of Richner-Hanhart Syndrome is generally determined on a case-by-case basis

Who gets Richner-Hanhart Syndrome? (Age and Sex Distribution)

• Richner-Hanhart Syndrome is a congenital disorder; the signs and symptoms are manifested during infancy
• The condition affects both males and females
• It is seen worldwide, and all racial and ethnic groups may be affected

What are the Risk Factors for Richner-Hanhart Syndrome? (Predisposing Factors)

• The risk factor for Richner-Hanhart Syndrome includes a positive family history of the condition
• Children born to consanguineous partners or spouses 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 Richner-Hanhart Syndrome? (Etiology)

Richner-Hanhart Syndrome is caused by genetic abnormalities which are passed down (through families) in an autosomal recessive manner.

• The syndrome develops due to mutation on the TAT gene on long arm of chromosome 16, which leads to an error in metabolism
• The condition causes enzyme deficiency (tyrosinemia) due to the body’s inability to breakdown the amino acid tyrosine
• An accumulation of this amino acid leads to development of the associated signs and symptoms that mainly affects the skin, eyes, and one’s mental health

Autosomal recessive: Autosomal recessive conditions are traits or disorders that occur when two copies of an abnormal gene have been inherited on a non-sex chromosome. If both parents are carriers of the gene causing an autosomal recessive condition, there is a 25 % chance that a child will get the defective recessive gene from both parents. They will therefore have the disease.   If, however, only one mutant copy of the gene is inherited, the individual will be a carrier of the condition, but will not be present with any symptoms. Children, born to two carriers, have a 25% chance of not receiving the gene from either parent, and will not have the disease and will not pass the gene on to their offspring. In the rare situation where both parents have the actual autosomal recessive condition, all their offspring will have two disease carrying genes and the disease is manifested.

What are the Signs and Symptoms of Richner-Hanhart Syndrome?

In general, the signs and symptoms associated with Richner-Hanhart Syndrome may vary from one individual to another. It may be mild or severe and may include:

• Skin signs and symptoms:
  • Yellow-white thickened skin papules and plaques
  • These abnormally-thickened skin lesions are observed on the palms of the hands and soles of the feet (palmoplantar keratoderma or PPK)
  • Punctate type of PPK (tiny bumps on palms and soles) is noted
  • The skin lesions are painful, and may be aggravated by friction/rubbing or scratching
  • There is an absence of transgrediens (i.e., contiguous extension of skin thickening beyond the palms and soles)
  • The skin thickening involves some portions of the palm and sole (localised keratoderma) in older children and adolescents
  • Excessive sweating (hyperhidrosis) may be noted
  • Normal activities that involve the use of one’s hands and feet may be severely affected
• Eye signs and symptoms:
  • Eye ulcer formations in both eyes (corneal ulcers)
  • High light-sensitivity (photophobia) during first year of childhood
  • Inflammation of the cornea (corneal keratitis)
  • Corneal opacity (cloudiness) and dystrophy
  • Decreased visual acuity
• Physical and mental growth associated signs and symptoms:
  • Developmental delays at infancy, early childhood, or during adolescence
  • A majority of children have poor mental growth and development
  • Delays in speech development

How is Richner-Hanhart Syndrome Diagnosed?

The diagnosis of Richner-Hanhart Syndrome may involve:

• 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). Elevated blood tyrosine levels may be noted
• 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
• General eye exam
• Fundoscopic (ophthalmoscopic) examination by an eye specialist, who examines the back part of the eye (or the fundus)
• Visual acuity test using a special and standardized test chart (Snellen chart)
• Slit-lamp examination
• Gonioscopy, a painless eye exam using special devices
• Visual evoked potential (VEP) test
• 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 Richner-Hanhart Syndrome?

The complications associated with Richner-Hanhart Syndrome may include:

• Emotional stress
• Cosmetic concerns
• Irreversible damage of cornea
• Loss of vision that may be permanent
• Severe mental retardation
• Disruption of normal life and activities if the condition is severe
• Decreased quality of life
• Lack of treatment response

How is Richner-Hanhart Syndrome Treated?

There is no cure for Richner-Hanhart Syndrome. The condition is managed through symptomatic treatment measures, which may involve the following:

• Dietary control of phenylalanine and tyrosine is necessary to control symptoms or prevent its worsening causing more severe mental retardation. Such restricted diets are instituted from infancy itself
• Additionally, vitamins, amino acids, and trace elements supplementation may be necessary
• Skin treatments may include:
  • Use of moisturizing creams and lotions; use of ointments containing vitamin D
  • Use of oral and systemic retinoids
  • Administration of keratolytics (medicine containing salicylic or lactic acid) 
  • Phototherapy
  • Surgical debridement (removal of thickened skin)
• Eye treatments may include:
  • Prescription of eye drops and ointments: However, the corneal lesions are not responsive to treatment with antiviral medications
  • In case of severe injury to the cornea, a keratoplasty (corneal graft) may be necessary
• Rehabilitation and special education programs, based on the severity of the condition
• Speech and language therapy, if necessary

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

How can Richner-Hanhart Syndrome be Prevented?

Currently, Richner-Hanhart Syndrome 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 such as hereditary palmoplantar keratoderma

What is the Prognosis of Richner-Hanhart Syndrome? (Outcomes/Resolutions)

• The prognosis of Richner-Hanhart Syndrome 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 Richner-Hanhart Syndrome:

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.