Incontinentia pigmenti in a newborn male infant with DNA confirmation

Long-term follow-up of neurological manifestations in a boy with incontinentia pigmenti

Incontinentia pigmenti (IP) is an X-linked dominant genodermatosis confined to females. It is usually lethal in males. However, the survival of some males has been reported in literature. We describe a long follow-up case of a 12-year-old male with IP and a normal karyotype but a genomic deletion of the NEMO gene in the Xq28 position in the form of somatic mosaicism. The patient showed severe ophthalmic abnormalities and neurological manifestations characterised by very mild cerebellar ataxia and a history of epilepsy that was severe at the beginning with West syndrome, become moderate overtime and is now resolved. Despite these neurological manifestations, probably related to the presence of at least some mutated cells in his brain, the long-term follow-up in this patient demonstrated good neurological and cognitive outcome.

NEMO, NFkappaB signaling and incontinentia pigmenti

The identification of mutations in the NEMO gene in humans with incontinentia pigmenti and several other genetic conditions has led to an appreciation of the multiple roles of signaling through the NFkappaB pathway, and how erroneous signalling contributes to disease. The finding that the disease results from a common, recurrent mutation was surprising given the high variability in patients' phenotypes and illustrates the role of X inactivation and selection in females. Recent advances in mouse models and in understanding the multiple roles of NEMO in the cell provide additional avenues to define the various roles of NEMO in NFkappaB signaling.

Surviving male with incontinentia pigmenti: a case report

Incontinentia pigmenti, or Block-Sulzberger Syndrome, is an X-linked dominant disorder with characteristic skin, hair, eye and tooth abnormalities. It is classically considered a male-lethal disorder with recurrent miscarriages of male foetuses. A few cases of surviving males with incontinentia pigmenti have been reported in the medical literature. This article reports the medical and dental findings of a boy diagnosed with incontinentia pigmenti.

Novel corneal features in two males with incontinentia pigmenti

Incontinentia pigmenti (IP) is a rare X linked genetic disorder, which predominantly affects females. The mutations are usually lethal in males. Two male cases are presented; a genetic mosaic for the common IP deletion and another in whom the genetic abnormality has not yet been characterised. Emphasis is placed on the ocular features present in this disorder and in particular a novel corneal feature and its possible aetiology.

The carboxyl-terminal region of IkappaB kinase gamma (IKKgamma) is required for full IKK activation

IkappaB kinase gamma (IKKgamma) (also known as NEMO, Fip-3, and IKKAP-1) is the essential regulatory component of the IKK complex; it is required for NF-kappaB activation by various stimuli, including tumor necrosis factor alpha (TNF-alpha), interleukin 1 (IL-1), phorbol esters, lipopolysaccharides, and double-stranded RNA. IKKgamma is encoded by an X-linked gene, deficiencies in which may result in two human genetic disorders, incontinentia pigmenti (IP) and hypohidrotic ectodermal dysplasia with severe immunodeficiency. Subsequent to the linkage of IKKgamma deficiency to IP, we biochemically characterized the effects of a mutation occurring in an IP-affected family on IKK activity and NF-kappaB signaling. This particular mutation results in premature termination, such that the variant IKKgamma protein lacks its putative C-terminal Zn finger and, due to decreased mRNA stability, is underexpressed. Correspondingly, IKK and NF-kappaB activation by TNF-alpha and, to a lesser extent, IL-1 are reduced. Mutagenesis of the C-terminal region of IKKgamma was performed in an attempt to define the role of the putative Zn finger and other potential functional motifs in this region. The mutants were expressed in IKKgamma-deficient murine embryonic fibroblasts (MEFs) at levels comparable to those of endogenous IKKgamma in wild-type MEFs and were able to associate with IKKalpha and IKKbeta. Substitution of two leucines within a C-terminal leucine zipper motif markedly reduced IKK activation by TNF-alpha and IL-1. Another point mutation resulting in a cysteine-to-serine substitution within the putative Zn finger motif affected IKK activation by TNF-alpha but not by IL-1. These results may explain why cells that express these or similar mutant alleles are sensitive to TNF-alpha-induced apoptosis despite being able to activate NF-kappaB in response to other stimuli.

Incontinentia pigmenti in a surviving male is accompanied by hypohidrotic ectodermal dysplasia and recurrent infection

Familial Incontinentia pigmenti (IP) is a rare X-linked dominant condition. The affected cases have characteristic skin lesions, hair, eye, teeth and nail abnormalities and may also have neurological problems. The diagnosis has traditionally been made on clinical grounds. Segregation analysis has suggested that it is lethal in males. Only one liveborn male has been reported who died at one day of age. Female cases of IP survive because of the moderating effects of Lyonization. This child was the affected son of a female with IP. He had a novel phenotype consistent with hypohidrotic ectodermal dysplasia with immune deficiency (HED-ID) but with additional features: he had major problems with hematological disturbances, failure to thrive due to malabsorption, recurrent infections, generalized osteosclerosis and lymphedema of his lower limbs. He also demonstrated some typical features of IP with a generalized reticular skin hyperpigmentation, sparse hair and delayed eruption of teeth. The gene for NEMO (NF-kappa B Essential Modulator) has recently been shown to be mutated in cases of IP. Furthermore, most (80%) of patients possess a recurrent genomic rearrangement that deletes part of the gene resulting in an inactive NEMO protein. In the male case described here, a NEMO stop codon mutation has been identified that has arisen de novo in his affected mother. This mutation is likely to have a less severe effect on NEMO activity and may explain why this child survived for two years and 7 months.

Atypical forms of incontinentia pigmenti in male individuals result from mutations of a cytosine tract in exon 10 of NEMO (IKK-gamma)

Familial incontinentia pigmenti (IP [MIM 308310]), or Bloch-Sulzberger syndrome, is an X-linked dominant and male-lethal disorder. We recently demonstrated that mutations in NEMO (IKK-gamma), which encodes a critical component of the NF-kappaB signaling pathway, were responsible for IP. Virtually all mutations eliminate the production of NEMO, causing the typical skewing of X inactivation in female individuals and lethality in male individuals, possibly through enhanced sensitivity to apoptosis. Most mutations also give rise to classic signs of IP, but, in this report, we describe two mutations in families with atypical phenotypes. Remarkably, each family included a male individual with unusual signs, including postnatal survival and either immune dysfunction or hematopoietic disturbance. We found two duplication mutations in these families, at a cytosine tract in exon 10 of NEMO, both of which remove the zinc (Zn) finger at the C-terminus of the protein. Two deletion mutations were also identified in the same tract in additional families. However, only the duplication mutations allowed male individuals to survive, and affected female individuals with duplication mutations demonstrated random or slight skewing of X inactivation. Similarly, NF-kappaB activation was diminished in the presence of duplication mutations and was completely absent in cells with deletion mutations. These results strongly indicate that male individuals can also suffer from IP caused by NEMO mutations, and we therefore urge a reevaluation of the diagnostic criteria.

Vascular and pigmented birthmarks

Vascular and pigmentary lesions compromise most birthmarks. Lesions range from uncommon, to very common, some being essentially normal variants. The natural history of these varies from being transient phenomena of no significance to permanent cutaneous findings that may be associated with significant systemic complications or diseases. This article describes the most frequently encountered clinically important birthmarks, including congenital nevi, hypopigmented lesions, vascular malformations and hemangiomas, discussing clinical presentation, diagnosis, and findings that should prompt early assessment and treatment.

Female mice heterozygous for IKK gamma/NEMO deficiencies develop a dermatopathy similar to the human X-linked disorder incontinentia pigmenti

IKK gamma/NEMO is the essential regulatory subunit of the I kappa B kinase (IKK), encoded by an X-linked gene in mice and humans. It is required for NF-kappa B activation and resistance to TNF-induced apoptosis. Female mice heterozygous for Ikk gamma/Nemo deficiency develop a unique dermatopathy characterized by keratinocyte hyperproliferation, skin inflammation, hyperkeratosis, and increased apoptosis. Although Ikk gamma+/- females eventually recover, Ikk gamma- males die in utero. These symptoms and inheritance pattern are very similar to those of incontinentia pigmenti (IP), a human genodermatosis, synthenic with the IKK gamma/NEMO locus. Indeed, biopsies and cells from IP patients exhibit defective IKK gamma/NEMO expression but normal expression of IKK catalytic subunits. This unique self-limiting disease, the first to be genetically linked to the IKK signaling pathway, is dependent on X-chromosome inactivation. We propose that the IKK gamma/NEMO-deficient cells trigger an inflammatory reaction that eventually leads to their death.