Patients with pigmentary mosaicism exhibit low rates of neurological abnormalities

Key takeaways:

• Only 14.8% of patients with pigmentary mosaicism exhibited neurological abnormalities.
• Of 10 patients with a combination of blocklike and blaschkolinear patterns, 50% experienced neurological abnormalities.

Neurological abnormalities were not highly associated with pigmentary mosaicism, with only 14.8% of patients with the disorder exhibiting developmental delay, seizures or microcephaly, according to a study.

“Pigmentary mosaicism (PM) is a descriptive term that encompasses a broad range of patterned hyper- and hypo-pigmented phenotypes thought to reflect underlying genetic mosaicism of skin cells,” Kyla Pagani, BS, of the department of dermatology at the University of Massachusetts Chan Medical School in Worcester, Massachusetts, and colleagues wrote. “Reported rates of neurologic abnormalities associated with PM have varied significantly in the literature.”

According to the authors, early neurological studies suggested there was a strong association between PM and neurological abnormalities (NA), with up to 90% of patients exhibiting this association. However, these reports seemed to have “a component of referral bias” and showed varying terminology, making clinical guidance challenging for patients with PM.

Pagani and colleagues conducted a retrospective chart review of 150 patients with PM (mean age at diagnosis, 4.27 years; 49.3% female) aged younger than 19 years to assess the association with neurological abnormalities across a 15-year period. Patients had a mean of 1.86 body areas involved, with 75.3% involving the trunk.

Mosaicism patterns, which were ascertained for 149 patients, included 40.3% with blaschkolinear patterns, 53% with blocklike patterns and 6.7% with a combination of the two patterns.

Results showed that 22 of 149 (14.8%) patients with PM had neurological abnormalities, including 12.8% (n = 19) with developmental delay, 3.4% (n = 5) with seizures and 0.7% (n = 1) with microcephaly. Further, nine of these 22 patients (40.9%) had hypopigmented blaschkolinear lesions.

Lesion color was not a factor in increased risk; however, a greater proportion of patients (50%) with a combination of both blocklike and blaschkolinear pigmentation patterns had NA, particularly seizures (P < .01), compared with those who had only blocklike (8.9%) or blaschkolinear (16.7%) patterns.

Additionally, patients with four or more affected body sites compared with those with less than four body sites affected were more likely to have NA (P < .01), as were patients with vs. without lower extremity involvement (P = .02). On the other hand, bilateral and unilateral distribution were not associated with NA.

Although the associations between NA and PM are lower than previous literature claimed, the authors emphasized that it is important to accurately counsel caregivers and providers about the risk for possible NA.

“We recommend assessment of patients on a case-by-case basis, documentation of the low associated risk of NA in the patient’s chart and to have a low threshold for referral to neurology for patients with neurological symptoms or signs,” Pagani and colleagues wrote.