Linear and whorled naevoid hypermelanosis in a patient with trisomy 4 mosaicism

Abstract

Linear whorled naevoid hypermelanosis (LWNH) is a rare skin condition, characterized by swirls and whorls of hyperpigmented macules distributed in a reticulate pattern along the lines of Blaschko. We report a 2-year-old boy who presented with linear and whorled hyperpigmentation on his trunk and limbs, following the lines of Blaschko. Hyperkinesia and developmental speech-language impairment were also present. A biopsy specimen showed increased pigmentation within the basal keratinocytes without incontinentia pigmenti. No chromosomal abnormality was found in peripheral blood samples. Chromosomal analysis of skin fibroblasts detected trisomy 4 mosaicism. This case shows for the first time an association of LWNH with trisomy 4 mosaicism. LWNH should not be considered a single entity, but a cutaneous expression of mosaicism.

Linear and Whorled Nevoid Hypermelanosis With Delayed Milestones

“…[4] Several case reports with genetic analysis have documented this to be the cause, most of them reporting trisomies of several different chromosomes. [5,6,7] These groups of diseases, termed as Blaschkoid dyspigmentation [8] include Linear and Whorled Nevoid Hypermelanosis (LWNH), incontinentia pigmenti, linear epidermal nevus, hypomelanosis of Ito and Goltz syndrome etc.…”

Trisomy 4 mosaicism: Delineation of the phenotype

“…In this report we describe a fourth case of an infant with trisomy 4 mosaicism. Only three cases have been reported previously in literature to date [Marion et al, ; Wieczorek et al, ; Brady et al, ; Lal and Di, ]. Based on these four patients the common phenotype of trisomy 4 mosaicism seems to include: IUGR (3/3), low birth weight/length/OFC (3/3), congenital heart defects (3/3), characteristic thumb anomalies (3/3), skin abnormalities (3/4) and several facial dysmorphisms (asymmetry of the face, eyebrow anomalies, low‐set ears, posteriorly rotated ears, and micro/retrognathia).…”

“…Cases involving trisomy 4 mosaicism have been rarely reported in literature. To our knowledge only three liveborn patients were described in whom this chromosomal aberration was detected [Marion et al, ; Wieczorek et al, ; Lal and Di, ]. In 2005 Brady et al provided long‐term follow‐up clinical information on one of these three patients (which was previously described at neonatal age) [Marion et al, ; Brady et al, ].…”