X-linked reticulate pigmentary disorder in a 4-year-old boy

A 4-year-old boy from a nonconsanguineous Chinese Han family was referred to the Department of Dermatology, The East Division of The First Affiliated Hospital, Sun Yat-sen University, China, because of dyschromatosis. He was born at full term through an uncomplicated delivery, and developed photophobia as well as bilateral lop ears at the age of 3 months. When he was 6 months old, he developed hypohidrosis that was over the whole body except the neck and outer aspects of the thighs, he also had mild fever of about 37.5°C during the summer or after physical activity, leading to erythema. Hereafter, generalized hyperpigmentation with mottled hypopigmentation developed over his whole body. He had normal growth and normal mental development, and there were no systemic manifestations as well as associations such as pruritus, pain, or burning sensations since his birth. His mother, and grandmother as well as the maternal grandmother on mother's side had multiple, asymptomatic, brownish macules in linear and whorled patterns over the trunk, axillae, groin and extremities after birth, which relieved after adolescence. His elder sister had cleft palate in addition to linear hyperpigmentation. During a 4-year follow-up, the patient’s hypohidrosis and the rise of body temperature had mild improvement although no treatments were ordered, while mottled hypopigmentation increased and was accompanied by more severe hyperpigmentation.
Cutaneous examination showed diffuse reticulate hyperpigmentation with mottled hypopigmentation over the whole body, associated with photophobia, coarse and dried skin, upswept frontal hairline and flared eyebrows (Figures 1 A–C). Skin biopsy was refused.
After informed written consent was obtained from the patient’s parents and other family members, DNA was extracted from peripheral blood of the patient and his family members according to standard methods. Then exome sequencing of the POLA1 gene was performed and revealed hemizygous mutation of NC_000023.10:g.24744696A>G for the patient and heterozygote for his mother and sister (Figures 2 A–C). Then a diagnosis of X-linked reticulate pigmentary disorder was confirmed.
X-linked reticulate pigmentary disorder [XLPDR; MIM301220], first described in a Canadian pedigree [1], is an exceptionally rare genodermatosis inherited as X-linked recessive trait [1–9]. In males, it is always characterized by diffused reticulate dyschromatosis with photophobia, dry skin and typical...


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