Inflammatory familial palmoplantar keratoderma: Greither's disease?

Hereditary palmoplantar keratodermas. Part I. Non-syndromic palmoplantar keratodermas: classification, clinical and genetic features

The term palmoplantar keratoderma (PPK) indicates any form of persistent thickening of the epidermis of palms and soles and includes genetic as well as acquired conditions. We review the nosology of hereditary PPKs that comprise an increasing number of entities with different prognoses, and a multitude of associated cutaneous and extracutaneous features. On the basis of the phenotypic consequences of the underlying genetic defect, hereditary PPKs may be divided into the following: (i) non-syndromic, isolated PPKs, which are characterized by a unique or predominant palmoplantar involvement; (ii) non-syndromic PPKs with additional distinctive cutaneous and adnexal manifestations, here named complex PPKs; (iii) syndromic PPKs, in which PPK is associated with specific extracutaneous manifestations. To date, the diagnosis of the different hereditary PPKs is based mainly on clinical history and features combined with histopathological findings. In recent years, the exponentially increasing use of next-generation sequencing technologies has led to the identification of several novel disease genes, and thus substantially contributed to elucidate the molecular basis of such a heterogeneous group of disorders. Here, we focus on hereditary non-syndromic isolated and complex PPKs. Syndromic PPKs are reviewed in the second part of this 2-part article, where other well-defined genetic diseases, which may present PPK among their phenotypic manifestations, are also listed and diagnostic and therapeutic approaches for PPKs are summarized.

Two families with Greither's syndrome caused by a keratin 1 mutation

Transgrediens et progrediens palmoplantar keratoderma, known as Greither's syndrome, was originally described in 1952 and is characterized by diffuse keratoderma of the palms and soles, extending to the back aspects (transgrediens) and involving the skin over the Achilles' tendon. Patchy hyperkeratosis also develops on the shins, knees, elbows, and sometimes on the skin flexures. We describe two unrelated families affected with Greither's syndrome, in which the same dominant missense mutation gave rise to the amino acid change N188S in K1. The previously reported cases of Greither's syndrome showed phenotypic variability suggestive of different underlying gene defects. Our findings suggest that at least some cases of Greither's syndrome are caused by keratin mutations.

Palmar hyperhidrosis: evidence of genetic transmission

BACKGROUND

Primary palmar hyperhidrosis is a condition marked by excessive perspiration and is reported to have an incidence of 1% in the Western population. It is a potentially disabling disorder that interferes with social, psychological, and professional activities. Over the past several years, several investigators have reported a positive family history in their patients treated for hyperhidrosis. To date, the cause is unknown; furthermore, epidemiologic data are scarce and inadequate.

METHODS

To characterize the genetic contribution to hyperhidrosis, we conducted a prospective study of 58 consecutive patients with palmar, plantar, or axillary hyperhidrosis treated with thoracoscopic sympathectomy from September 1993 to July 1999. Forty-nine of the 58 probands volunteered family history data for these analyses (84% response rate). A standardized questionnaire was administered during the postoperative visit or by phone interview, and a detailed family history was obtained. The same questionnaire was also administered to a set of 20 control patients. The familial aggregation of hyperhidrosis has been quantified by estimating the recurrence risks to the offspring, parents, siblings, aunts, uncles, and cousins of 49 probands and 20 controls. We estimated the penetrance by use of a genetic analysis program.

RESULTS

Thirty-two of 49 (65%) reported a positive family history in our hyperhidrosis group, and 0% reported a positive family history in our control group. A recurrence risk of 0.28 in the offspring of probands compared with frequency of 0.01 in the general population provides strong evidence for vertical transmission of this disorder in pedigrees and is further supported by the 0.14 risk to the parents of the probands. The results indicate that the disease allele is present in about 5% of the population and that one or two copies of the allele will result in hyperhidrosis 25% of the time, whereas the normal allele will result in hyperhidrosis less than 1% of the time.

CONCLUSIONS

We conclude that primary palmar hyperhidrosis is a hereditary disorder, with variable penetrance and no proof of sex-linked transmission. However, this does not exclude other possible causes, and we anticipate that genetic confirmation of this disorder may lead to earlier diagnoses and advances in medical and psychosocial interventions.

Essential hyperhidrosis in Turner syndrome

We describe two Turner patients suffering from severe essential hyperhidrosis. Since both disorders are rare (1 in 5000 live female births for Turner syndrome and approximately 1 in 1000 persons for essential hyperhidrosis), our finding of two patients with these disorders in a total of 150 essential hyperhidrosis patients may suggest that this association is more frequent in Turner syndrome than previously thought.

Palmoplantar keratoderma and associated syndromes

This article focuses on the current state of knowledge concerning the characterization and classification of palmoplantar keratoderma and associated syndromes. In addition, therapeutic options are discussed. Exact diagnosis enables dermatologists to give patients accurate genetic counseling and may help to detect underlying defects or proneness to cancer. Furthermore, precise classification of this disease facilitates the use of the most efficient therapeutic modalities. Important criteria for the classification of palmoplantar keratoderma are the mode of transmission, age at onset, and distribution of the keratoderma. The disorder may be diffuse or focal; it may be restricted to the palms and soles or also involve the dorsal aspects of the hands and feet. Psoriatic-like lesions in other parts of the body may occur in certain variants. The association of other signs and symptoms may provide diagnostic clues. Ultrastructural investigation will show diagnostic features in some types of palmoplantar keratoderma, and biochemical analysis may be helpful in the classification of keratoderma. In the future, the most accurate diagnosis will be the identification of the genetic defect and its chromosomal localization.