A case of ankyloblepharon, ectodermal dysplasia, and cleft lip/palate syndrome with ectrodactyly: are the p63 syndromes distinct after all?

Overlap between EEC and AEC syndrome and immunodeficiency in a preterm infant with a TP63 variant

Pathogenic variants in the transcription factor TP63 gene cause a variety of clinical phenotypes, such as ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome and ankyloblepharon-ectodermal dysplasia-clefting (AEC) syndrome. Historically, TP63-related phenotypes have been divided into several syndromes based on both the clinical presentation and location of the pathogenic variant on the TP63 gene. This division is complicated by significant overlap between syndromes. Here we describe a patient with clinical characteristics of different TP63-associated syndromes (cleft lip and palate, split feet, ectropion, erosions of the skin and corneas), associated with a de novo heterozygous pathogenic variant c.1681 T>C, p.(Cys561Arg) in exon 13 of the TP63 gene. Our patient also developed enlargement of the left-sided cardiac compartments and secondary mitral insufficiency, which is a novel finding, and immune deficiency, which has only rarely been reported. The clinical course was further complicated by prematurity and very low birth weight. We illustrate the overlapping features of EEC and AEC syndrome and multidisciplinary care needed to address the various clinical challenges.

Differentially Expressed Genes in EEC and LMS Syndromes

Objectives

Ectrodactyly ectodermal dysplasia cleft lip/palate (EEC) syndrome and limb-mammary syndrome (LMS) share a similar phenotype and the same pathogenic gene, which complicates the ability to distinguish between these diagnoses. The current study aims to identify a potential and practical clinical biomarker to distinguish EEC from LMS.

Methods

Two EEC pedigrees and one LMS pedigree that have been previously reported were reanalyzed. After confirmation of the causative mutations for these new patients, whole-genome expression microarray analysis was performed to assess the molecular genetic changes in these families.

Results

Five new patients with classic symptoms were reported, and these individuals exhibited the same mutation as their relatives (c.812 G>C; c.611G>A; and c.680G>A). According to the whole genome expression results, the EEC patients exhibited different gene expression characteristics compared with the LMS patients. More than 5,000 genes were differentially expressed (changes >2 or <0.5-fold) among the EEC patients, LMS patients and healthy individuals. The top three altered pathways have been implicated in apoptosis, the hematopoietic cell lineage and the Toll-like receptor signaling pathway.

Conclusion

Our results provide additional clinical and molecular information regarding EEC and LMS and suggest that peripheral blood cytokines may represent a promising clinical biomarker for the diagnosis of these syndromes.

ADULT syndrome due to an R243W mutation in TP63

Acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome is a rare, autosomal dominant form of ectodermal dysplasia due to TP63 mutations. ADULT syndrome is much less common than the more classical forms of TP63-associated ectodermal dysplasias, such as ectrodactyly-ectodermal dysplasia-cleft lip/palate (EEC) syndrome and ankyloblepharon-ectodermal defects-cleft lip/palate syndrome. ADULT syndrome is characterized by ectrodactyly, syndactyly, and excessive freckling, in addition to more typical ectodermal defects, including hypodontia, lacrimal duct anomalies, hypotrichosis, and onychodysplasia. Unlike some of the other TP63-associated ectodermal dysplasias, ADULT syndrome lacks clefting and ankyloblepharon. Here, we report a three-generation family with ADULT syndrome due to an R243W mutation in TP63, a mutation that has previously been described in one patient with ADULT syndrome and eight unrelated patients with EEC syndrome.