Uncovering incontinentia pigmenti: From DNA sequence to pathophysiology

Central nervous system anomalies in 41 Chinese children incontinentia pigmenti

INTRODUCTION

Incontinentia pigmenti (IP) is a rare neuroectodermal dysplasia caused by a defect in the IKBKG gene. The pathogenesis of central nervous system injury is believed to be related to microvascular ischemia. Currently, few treatment strategies are available for the inflammatory phase.

MATERIALS AND METHODS

This retrospective descriptive analysis included the clinical data of 41 children with IP collected from 2007 to 2021 in Xi'an, China, comprising clinical characteristics, imaging findings, blood cell analysis, skin histopathology, and genetic data.

RESULTS

Fourteen children (34%) aged 4 days to 5 months exhibited clinical signs and symptoms, including convulsions, delayed psychomotor development following neurological damage, and revealed significant MRI abnormalities, including ischemia, hypoxia, cerebral hypoperfusion, hemorrhage, encephalomalacia, and cerebral atrophy. Eight of the 24 patients (33%) presented with retinal vascular tortuosity and telangiectasis, accompanied by neovascularization and hemorrhage. Thirty-eight children (93%) had elevated eosinophils (mean: 3.63 ± 4.46 × 109), and 28 children (68%) had significantly elevated platelets (mean: 420.16 ± 179.43 × 109). Histopathology of skin revealed microvascular extravasation and vasodilation with perivascular and intravascular eosinophilic infiltration.

CONCLUSION

Brain injury in IP occurs during infancy until 5 months of age, which is also the acute dermatitis phase accompanied by eosinophilia and an increased platelet count. This study provides evidence of microvascular damage to the skin and fundus during the inflammatory phase. The mechanism of microvascular damage may be similar to that in the brain.

Novel IKBKG gene mutations in incontinentia pigmenti: report of two cases

Incontinentia pigmenti (IP), an X-chromosome dominant genodermatosis caused by mutations in the IKBKG/NEMO gene, is a rare disease affecting the skin, teeth, eyes, and central nervous system. Here, we report two pedigrees of IP and detection of two novel mutations in the IKBKG gene associated with IP via genetic analysis. In addition, different gene mutation types can present with different clinical phenotypes, and the same gene mutation type can show different clinical phenotypes. This study provides clinical cases for further study of the genotype and phenotype of IP and enriches the mutation spectrum of IKBKG gene, which provides a basis for genetic counseling and genetic diagnosis of IP in the future.

Incontinentia Pigmenti: A Case Report of Early Clinical Symptoms in a Lack of Family Inheritance Positive Result

Background

Incontinentia pigmenti (IP), also known as Bloch-Sulzberger syndrome, is an X-linked dominant genetic disease involving multiple systems. Previous literature has not reported the case of parents with negative genetic test results, and typical early clinical symptoms and auxiliary inspection results were also lacking.

Case Report

A female child was found to have broken skin immediately after birth with no family inheritance disease, and the area of the broken skin increased. Immediately afterward, Head magnetic resonance imaging (MRI) showed multiple blood lesions in the brain. Then, the wide-angle digital retinal imaging system suggesting that fundus fluorescein angiography showed fundus vascular loop-like changes. And blood genetic testing showed that exons 4-10 of the NEMO gene located in Xq28 were deleted. The patient was eventually diagnosed with IP. However, her parents were a non-consanguineous healthy couple, with no specific skin, oral, or perineal diseases. And her parents' blood genetic testing showed that the parents and sisters of the patient did not have the NEMO gene exon deletion of Xq28.

Conclusion

This case demonstrates the process from suspected neonatal IP cases without familial inheritance to diagnosis, which showed the typical early clinical symptoms and auxiliary inspection results. This case showed that the parents of patients with IP do not necessarily have clinical symptoms and positive symptoms of genetic testing results.