Familial progressive hypermelanosis in Indian monozygotic twins

Familial progressive hyper- and hypopigmentation: a report on a Chinese family and evidence for genetic heterogeneity

BACKGROUND

Familial progressive hyper- and hypopigmentation (FPHH) is a rare genodermatosis that is characterized by diffuse hyper- and hypopigmented spots on the skin and mucous membranes. It is caused by a pathogenic mutation of the KITLG gene.

OBJECTIVES

To investigate the clinical features and mutation of the KITLG gene in a Chinese family with FPHH.

METHODS

Histopathological and immunohistochemical analysis of lesions from the proband was performed. The KITLG gene was screened for the presence of mutations.

RESULTS

A Chinese family containing 14 individuals with FPHH was described, and the proband was a 5-year-old girl showing diffuse hyper- and hypopigmented lesions on her extremities and trunk. Histopathological and immunohistochemical staining for S100 and HMB45 of skin biopsy specimens from the hyperpigmented areas showed a striking increase in melanin throughout the epidermis, especially in the basal cell layer, and staining of hypopigmented area specimens displayed lower levels of melanin in the epidermis. Mutation analysis of the KITLG gene was performed, but no mutation was found.

STUDY LIMITATIONS

The new pathogenic gene was not found.

CONCLUSION

A family with FPHH was described. Analysis revealed that its members did not have any mutations of the KITLG gene, which provided evidence for genetic heterogeneity of this genodermatosis.

Universal acquired melanosis in siblings

Generalized pigmentation in a child may be seen in a variety of disorders which can be clinically differentiated. Accuracy of diagnosis can be increased by classifications based on both clinical and histological findings. The authors report a case of siblings in whom hyperpigmentation started at age of about 6 mo and was progressing. Histology of skin revealed shortening and blunting of rete ridges with presence of melanocytes in stratum basal layer. This is a rare type of hypermelanosis and termed as universal acquired melanosis or carbon baby syndrome. This is a rare presentation and first case report in siblings.