Acropigmentation of Kitamura with immigration delay disease: A rare entity.

Reticulate acropigmentation of Kitamura (RAK) is a rare, autosomal dominant disorder first described in Japan characterised by a reticulate pattern of slightly atrophic, angulated, hyperpigmented macules affecting the acral areas of the body. We hereby report a case of RAK in a young Indian male with adermatoglyphia that has not been previously reported in the literature.

INTRODUCTION

Reticulate acropigmentation of Kitamura (RAK) was first described by Kitamura and Akamatsu in Japanese patients in 1943.[1] It is characterized by angulated, slightly atrophic, hyperpigmented macules that are arranged in a reticulate pattern typically on the dorsal aspect of hands and feet. The condition is inherited in an autosomal dominant fashion and skin changes begin to develop during childhood.[2] Adermatoglyphia or ‘immigration delay disease’ is an extremely rare disorder characterized by congenital absence of epidermal ridges on the fingers, palms, toes, and soles, and eventually, fingerprints. We are reporting a rare entity of RAK with adermatoglyphia in a young Indian male.

CASE REPORT

A 22-year-old male presented with a 10-year history of asymptomatic and progressive brownish-black discoloration over the dorsa of hands and feet. Pigmentation progressed slowly to involve the dorsal and ventral surfaces of the extremities, neck, and chest. His past medical history was unremarkable. There was no history of photosensitivity. There was no history of handling any chemical directly or any significant history of drug intake. There was no similar case in the family and no history of consanguinity among parents.

Cutaneous examination revealed punctate, irregular, slightly atrophic, brown macules arranged in a reticulate pattern on dorsa of hands and feet, the extensor and flexor surfaces of forearms, flexor aspects of neck and chest [Figure 1]. Brownish pigmentation was also present on the palms with absent dermatoglyphics distal to the distal crease and the fingernails were dystrophic [Figure 2]. Plantar pitting was also present [Figure 3]. Facial skin and teeth were normal. Systemic examination did not reveal any abnormality. Routine investigations including complete blood counts, urinalysis, liver function tests, renal function tests, and serum electrolytes were within normal limits. The Venereal Disease Research Laboratory test and ELISA for HIV were nonreactive.

Figure 1

Brownish black macules on dorsa of hands with dystrophic left middle fingernail

Figure 2

Absence of dermatoglyphics distal to the distal crease

Figure 3

Plantar pitting

Skin biopsy was taken from the left forearm, which showed digitate and filiform elongation of rete ridges, with clumps of heavy melanin pigmentation at their tips. There was melanin incontinence in the papillary dermis [Figure 4]. This confirmed the diagnosis of RAK.

Figure 4

Digitate elongation of rete ridges with clumps of heavy melanin pigmentation at the tips and melanin incontinence in papillary dermis (H and E, ×40)

DISCUSSION

Reticulate acropigmentation of Kitamura is a rare genodermatoses that was first described in Japan. However, rare familial cases have been described from India, Turkey, Iran, Saudi Arabia, Italy, and Latin America.[3] It follows an autosomal dominant mode of inheritance with high penetrance.

The characteristic presentation of RAK is pigmented, angulated, irregular freckle-like lesions with atrophy on the surface arranged in a reticulate pattern on the dorsa of hands and feet.[2] The lesions usually start in the first and second decades of life and gradually extend onto the extremities and rarely on the face and eyelids. The lesions gradually darken over time. Sunlight may aggravate the condition. Pits and breaks in the dermatoglyphics are found over the palms, soles, and dorsal phalangeal surfaces.[4] Our patient presented with adermatoglyphia distal to the distal crease, dystrophic fingernails and plantar pits that was unusual.

Histopathological examination showed characteristic epidermal atrophy associated with club-like elongation of the rete ridges and an excess of melanin in the basal layer.[5]

The differential diagnosis of RAK include diseases presenting with reticulate or punctuate hyperpigmentation such as dyskeratosis congenita, dyschromatosis universalis hereditaria, Franceschetti-Jadassohn's syndrome, dermatopathia pigmentosa reticularis, reticulate acropigmentation of Dohi (RAD), and Dowling-Degos disease (DDD).[6]

Reticulate acropigmentation of Dohi is also an acral type of dyschromatosis (dyschromatosis symmetrica herediteria) that usually starts in infancy or early childhood as hypopigmented and hyperpigmented macules over the dorsa of the hands and feet.[7] The differentiation between RAD and RAK is based on clinical and histological findings. In RAK, there are usually no hypopigmented macules and histologically hyperpigmented lesions show epidermal atrophy, elongation of rete ridges and increased number of DOPA positive melanocytes, while in RAD only increased or decreased basilar pigmentation is present in hyperpigmented or hypopigmented lesions respectively with occasional melanin incontinence in hypopigmented lesions. In Dyschromatosis universalis hereditaria mottled pigmentation is present involving the trunk, extremities, face, palms, soles and occasionally oral mucosa. Dyskeratosis congenita follows autosomal dominant mode of inheritance and is caused by dyskerin gene mutation. Reticulate telangiectatic hyperpigmentation interspersed with areas of hypopigmentation involves face, neck, trunk and upper thighs with sparing of distal extremities as in RAK. The pharyngeal, oral, anorectal mucosae show leukokeratosis while nails are dystrophic in dyskeratosis congenital. Dermatopathia pigmentosa reticularis in an autosomal dominant disorder and reveals a characteristic triad of generalized reticulate hyperpigmentation, non-cicactricial alopecia and onychodystophy.

Recently, there have been increasing reports on the coexistence of RAK and DDD in the same patient.[8] A mutation in ADAM 10 gene encoding a zinc metalloprotease, a disintegrin, and metalloprotease domain-containing protein 10 (ADAM 10) has been identified in RAK family.[9] ADAM 10 is known to be involved in the ectodomain shedding of various substrates in the skin. KRT 5 mutation has been thought to be causative in DDD.[10] Thus, genetic studies reveal RAK and DDD as distinct entities.

Congenital absence of epidermal ridges is a rare condition known as adermatoglyphia. It has recently been coined as “immigration delay disease,” because affected individuals report significant difficulties entering countries that require fingerprint recording.[11] The factors underlying the formation of epidermal ridges during embryonic development and their pattern remain unknown but are likely to include both genetically determined traits as well as environmental elements and involve some form of interactions between the mesenchymal, dermal, and epidermal elements. At 24 week's post-fertilization, the epidermal-ridge system displays an adult morphology that remains permanent without any modification throughout life[12] Till date, only four families with congenital absence of fingerprints have been described. In three of these families, additional features such as congenital facial milia, skin blisters, and fissures associated with heat or trauma were reported.[13] A number of complex syndromes such as dyskeratosis congenita, Naegeli-Franceschetti-Jadassohn syndrome, dermatopathia pigmentosa reticularis, and Bason syndrome also feature adermatoglyphia.[14]

The disease phenotype has been mapped to 4q22. Gene located in this interval is SMARCAD1, a member of the SNF subfamily of the helicase protein family. Genetic studies till date implicate a skin-specific isoform of SMARCAD1 in the regulation of dermatoglyphics development.[15]

Nousbeck et al. analyzed candidate KRT 14 gene (implicated in dyskeratosis congenita and Naegeli-Franceschetti-Jadassohn syndrome) in a four-generation pedigree with adermatoglyphia, but did not find any mutations.[15] Though SMARCAD1 mutation has not been recorded in any of the reticulate pigmentary disorders, adermatoglyphia is a chief feature associated with many of them. Thus, more genetic studies are required to prove their association and causation.

Though adermatoglphia has been reported with complex syndromes and reticulate pigmentary disorders, it has never been reported in association with RAK. Thus, our case is a unique addition to the wardrobe of disorders associated with immigration delay disease.