Acanthosis Nigricans

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Retrieved

2019-09-22

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Omim

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Clinical Features

Acanthosis nigricans consists of thickening and hyperpigmentation of the skin of the entire body but especially in flexural areas. In an affected mother and daughter reported by Tasjian and Jarratt (1984), skin lesions were first noted in infancy.

Chuang et al. (1995) reported familial acanthosis nigricans affecting a 35-year-old woman, her 7-year-old son, and 5-year-old daughter. Absence of the eyebrows and eyelashes was also present in the affected members of this family. The mother had no axillary hair and her pubic hair was sparse. The boy also suffered from congenital heart disease and a congenital cataract in the left eye. Chuang et al. (1995) suggested that the combination of acanthosis nigricans and ectodermal defects in this family may represent a distinct nosologic entity. They referred to the hair problem as madarosis (loss of the eyebrows or of the eyelashes).

Inheritance

In 26 patients with malignant acanthosis nigricans (secondary to visceral carcinoma), Curth and Aschner (1959) found no other affected persons in the family. However, they identified families with benign acanthosis nigricans in successive generations, 3 in 1 family and 2 in 2 others, including instances of male-to-male transmission.

Jung et al. (1965) observed affected mother and daughter.

Lawrence et al. (1971) described a patient with acanthosis nigricans inherited from the father and telangiectasia (187300) inherited from the mother.

Using data from 397 participants from 2 Mexican-American family studies, Burke et al. (2000) investigated the heritability of acanthosis nigricans and its genetic correlation with other diabetes risk factors. They examined acanthosis nigricans as both a continuous trait and a dichotomous trait by means of a previously described validated scale. The results indicated that the heritability for the condition, when examined as a continuous trait, was high (0.58 +/- 0.10) and statistically significant (P less than 0.001). The heritability as a dichotomous trait was estimated to be moderate (0.23 +/- 0.05) and was also significant (P = 0.018). The additive genetic correlations between acanthosis nigricans and type 2 diabetes and its risk factors, including body mass index and fasting insulin, were high or moderately high and statistically significant. The random environmental correlations, by contrast, were low and statistically insignificant. These data suggested that genes that influence acanthosis nigricans have pleiotropic effects on diabetes and its risk factors.

In addition to the association with insulin resistance (see 610549), Seip syndrome (269700), and malignancy, acanthosis nigricans can be drug-induced; nicotinic acid, diethylstilbestrol, oral contraceptives, and exogenous glucocorticoids have been incriminated. Clear mendelian inheritance is seen when acanthosis nigricans is part of syndromes, e.g., Seip syndrome. Autosomal dominant acanthosis nigricans should be studied for insulin resistance.