Syndromic and Nonsyndromic Systemic Associations of Congenital Lacrimal Drainage Anomalies: A Major Review

PURPOSE

To review and summarize the syndromic, nonsyndromic, and systemic associations of congenital lacrimal drainage anomalies.

METHODS

The authors performed a PubMed search of all articles published in English on congenital lacrimal anomalies (1933-2016). Patients of these articles were reviewed along with the literature of direct references to syndromes and other systemic associations. Data reviewed included syndromic descriptions, systemic details, demographics, lacrimal presentations, management, and outcomes.

RESULTS

Syndromic and systemic associations with congenital lacrimal drainage disorders are not known to be common. Although familial presentations have been reported, the inheritance patterns are unclear for most anomalies. There is an increasingly growing evidence of a genetic basis to many lacrimal anomalies. However, few syndromes have either widespread or are frequently associated with lacrimal anomalies. Few sequences of distinct lacrimal presentations and intraoperative findings are seen. Surgical challenges in these patients are distinct and a thorough pre and intraoperative anatomical assessment, detailed imaging when indicated, and assessment and correction of associated periocular and facial abnormalities may facilitate good outcomes.

CONCLUSIONS

Lacrimal drainage anomalies associated with syndromic and nonsyndromic systemic conditions have certain unique features of their own and their surgical and anesthesia challenges are distinct. Diagnosis of congenital lacrimal drainage anomalies should prompt consideration of the possible presence of associated systemic abnormalities.

Cleft palate and ADULT phenotype in a patient with a novel TP63 mutation suggests lumping of EEC/LM/ADULT syndromes into a unique entity: ELA syndrome

Acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome is a rare condition belonging to the group of ectodermal dysplasias caused by TP63 mutations. Its clinical phenotype is similar to ectrodactyly-ectodermal dysplasia-cleft lip/palate (EEC) and limb-mammary syndrome (LMS), and differs from these disorders mainly by the absence of cleft lip and/or palate. We report on a 39-year-old patient who was found to be heterozygous for a c.401G > T (p.Gly134Val) de novo mutation of TP63. This patient had the ADULT phenotype associated with cleft palate. Our findings, rather than extend the clinical spectrum of ADULT syndrome, suggest that cleft palate can no longer be considered an element for differential diagnosis for ADULT, EEC, and LMS. Our data, added to other reports on overlapping phenotypes, support the combining of these three phenotypes into a unique entity that we propose to call "ELA syndrome," which is an acronym of ectrodactyly-ectodermal dysplasia-cleft lip and palate, limb-mammary, and ADULT syndromes.

Congenital bilateral amazia associated with bilateral choanal atresia

Congenital absence of breast development is a very rare abnormality. It may present as an isolated finding or it may be accompanied by other congenital anomalies. Here we report on a 13.5-year-old girl presented to our pediatric endocrinology clinic because of lack of breast development. She had pubarche since the age of 10 years and was regularly menstruating since the age of 12 years. The patient's medical history was positive for bilateral complete choanal atresia that was diagnosed and corrected soon after birth. Physical examination was unremarkable except for bilateral amazia, that is, absence of palpable breast tissue and hypoplastic areolae, whereas both nipples were formed. Renal ultrasonography and chest radiography were normal. The coexistence of congenital bilateral amazia and bilateral complete choanal atresia suggests that these rare disorders may be related etiologically. The patient is scheduled for breast augmentation.

Pattern of p63 mutations and their phenotypes--update

Heterozygous mutations in the transcription factor gene p63 cause at least six different syndromes with various combinations of ectodermal dysplasia, orofacial clefting and limb malformations. Here we will present an update of mutations in the p63 gene together with a comprehensive overview of the associated clinical features in 227 patients. These data confirm the previously recognized genotype-phenotype associations. Moreover, we report that there is a large degree of clinical variability in each of the p63-associated disorders. This is illustrated by the different phenotypes that are seen for the five-hotspot mutations that explain almost 90% of all EEC syndrome patients.

Delineation of the ADULT syndrome phenotype due to arginine 298 mutations of the p63 gene

The ADULT syndrome (Acro-Dermato-Ungual-Lacrimal-Tooth, OMIM 103285) is a rare ectodermal dysplasia associated with limb malformations and caused by heterozygous mutations in p63. ADULT syndrome has clinical overlap with other p63 mutation syndromes, such as EEC (OMIM 604292), LMS (OMIM 603543), AEC (106260), RHS (129400) and SHFM4 (605289). ADULT syndrome characteristics are ectrodactyly, ectodermal dysplasia, mammary gland hypoplasia and normal lip and palate. The latter findings allow differentiation from EEC syndrome. LMS differs by milder ectodermal involvement. Here, we report three new unrelated ADULT syndrome families, all with mutations of arginine 298. On basis of 16 patients in five families with R298 mutation, we delineate the ADULT syndrome phenotype. In addition, we have documented a gain-of-function effect on the dNp63gamma isoform caused by this mutation. We discuss the possible relevance of oral squamous cell carcinoma in one patient, who carries this p63 germline mutation.

Immunohistochemical expression of p63 in human prenatal tooth primordia

The aim of this study was to investigate the expression of the p63 gene in normal human tooth buds at different gestational stages. This is the first detailed study of p63 expression in normal human prenatal tooth primordia. The material consisted of sections of the midaxial tissue block from the cranial base of three human fetuses of gestational ages (GA) 11, 15, and 21 weeks. The sections included tooth primordia representing cap stages and bell stages of human tooth morphogenesis. In the present study, immunostaining was carried out using the primary antibody, monoclonal mouse anti human p63 protein, clone 4A4. The sections were counterstained with hematoxylin Mayer. p63 immunoreactivity was identified by microscopy. The study showed a positive reaction of p63 in both the cap stage and the bell stage. In both stages, positivity was observed in the cells of the oral mucosa, the inner and outer enamel epithelium, and in the primary and secondary dental lamina. In the early cap stage, there is a strong positive reaction to p63 in the enamel knot, but not in the late cap stage. We suggest that p63 may have an important regulatory function in the enamel knot.

Acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome: Report of a child with phenotypic overlap with ulnar-mammary syndrome and a new mutation inTP63

We report on a new patient with clinical findings consistent with acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome. The child had sparse hair, extensive freckling, lacrimal duct stenosis, oligodontia, dystrophic nails, reduced sweating, and bilateral athelia. Examination of his hands showed ulnar ray hypoplasia with bilateral fifth finger brachydactyly and camptodactyly. He also had surgical repair of an imperforate anus. Mutation analysis of TP63 showed a single nucleotide substitution, c.G518A, predicting a novel missense mutation, p.V114M in exon 4. This is the third mutation to be reported in TP63 in ADULT syndrome.

p63 gene analysis in Mexican patients with syndromic and non-syndromic ectrodactyly

Ectrodactyly is a congenital limb malformation that involves a central reduction defect of the hands and/or feet which is frequently associated with other phenotypic abnormalities. The condition appears to be genetically heterogeneous and recently it has been demonstrated that mutations in the p63 gene, a homologue of the tumor suppressor gene p53, are the cause of at least four autosomal dominant genetic syndromes which feature ectrodactyly: ectrodactyly, ectodermal dysplasia, and facial clefting (EEC), split hand/split foot malformation (SHFM), limb-mammary syndrome (LMS), and acro-dermato-ungual-lacrimal-tooth syndrome (ADULT). In this study, genetic analysis of the p63 gene in a group of 13 patients with ectrodactyly (syndromic and isolated) was performed. Four patients with syndromic ectrodactyly had p63 heterozygous point mutations that affect the DNA binding domain of the protein. One of these subjects exhibited the typical features of EEC syndrome as well as ankyloblepharon being, to our knowledge, the first case combining these traits. This finding supports the view of a clinical overlap in this group of autosomal dominant syndromes caused by p63 mutations and demonstrates that there are exceptions in the previously established p63 genotype-phenotype correlation.

P63 gene mutations and human developmental syndromes

The P63 gene is a recently discovered member of the p53 family. While P53 is ubiquitously expressed, p63 is expressed specifically in embryonic ectoderm and in the basal regenerative layers of epithelial tissues in the adult. Complete abrogation of P63 gene function in an animal model points to the relevance of P63 for the proper development of ectodermally derived tissues. The p63 knockout mouse dies at birth and has truncation of the limbs, as well as absence of epidermis, prostate, breast, and urothelial tissues, apparently reflecting ectodermal stem cell loss. A number of dominant human syndromes have been mapped to chromosome 3q27 and ultimately to mutations in the p63 gene. These syndromes have abnormal limb development and/or ectodermal dysplasia and include ectrodactyly, ectodermal dysplasia, clefting syndrome; ankyloblepharon, ectodermal dysplasia, clefting syndrome; acro-dermato-ungual-lacrimal-tooth syndrome; limb-mammary syndrome; as well as nonsyndromic split hand/foot malformation. The pattern of heterozygous mutations is distinct for each of these syndromes. Consistent with this syndrome-specific mutational pattern, the functional consequences of mutations on the p63 proteins also vary, invoking dominant-negative and gain-of-function mechanisms rather than a simple loss of function.

Prenatal diagnosis of acro-dermatoungual-lacrimal-tooth syndrome, a dominantly inherited ectrodactyly

As part of an assessment for preeclampsia, a prenatal sonogram performed on a pregnant woman at 33 weeks 4 days' gestation showed ectrodactyly in all 4 fetal extremities. The woman's husband had a history of hand abnormalities but was unaware that his condition was genetic. His examination was notable for ectrodactyly, small, peg-shaped teeth, microretrognathia, nail dysplasia, and a history of lacrimal duct blockage in infancy, consistent with a diagnosis of acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome. Acro-dermato-ungual-lacrimal-tooth syndrome is inherited as an autosomal dominant condition. Many of the inherited ectrodactyly syndromes are now known to be due to mutations in the p63 gene. This case, in which a prenatal sonographic diagnosis of ADULT syndrome was made, illustrates the importance of following up on a history of paternal hand anomalies.

Splitting p63

Causative TP63 mutations have been identified in five distinct human developmental disorders that are characterized by various degrees of limb abnormalities, ectodermal dysplasia, and facial clefts. The distribution of mutations over the various p63 protein domains and the structural and functional implications of these mutations establish a clear genotype-phenotype correlation.

Ectrodactyly and Germany's eugenics law of 14 July 1933

The family reported herein serves as a genetically and historically important vignette on the issues of nonpenetrance (versus germinal mosaicism) in nonsyndromic autosomal dominant ectrodactyly and the Eugenics Law of Germany of 14 July 1933, which was used to coerce the sterilization of the propositus despite infertility in his first marriage. In a sibship of seven children (with normal parents), three boys were affected. The propositus (adoptive grandfather of the author) was the patient of Paul Leopold Friedrich and Georg Perthes, who published their observations on the propositus. Except for an adopted daughter, the propositus was childless. His two affected brothers each had an affected child, and the father- to son transmission confirmed the hypothesis of autosomal dominant inheritance. The issue of nonpenetrance versus germinal mosaicism in ectrodactyly was debated by Auerbach [1956:Ann Hum Genet 20:266-269] and Vogel [1958:Ann Hum Genet 22:132-137], and remains unresolved.

Mutations in the p53 homolog p63: allele-specific developmental syndromes in humans

p63 is the most recently discovered but most ancient member of the p53 family. In marked contrast to p53, p63 is highly expressed in embryonic ectoderm and in the basal, regenerative layers of many epithelial tissues in the adult. The p63-knockout mouse dies at birth and lacks limbs, epidermis, prostate, breast and urothelial tissues, apparently owing to the loss of stem cells required for these tissues. Significantly, several dominant human syndromes involving limb development and/or ectodermal dysplasia have been mapped to chromosome 3q27 and ultimately the gene encoding p63. The heterozygous p63mutations are distinct for each of the syndromes and are thought to act through both dominant-negative and gain-of-function mechanisms rather than a loss-of-function haploinsufficiency. The allele specificity of these syndromes offers unique molecular insights into the poorly understood actions of p63 in limb development, ectodermal-mesodermal interactions and stem cell maintenance.

TP63 gene mutation in ADULT syndrome

TP63 gene mutations have recently been shown to be disease causing in EEC and SHFM. Two other overlapping syndromes with ectrodactyly as a major feature, have been mapped to chromosome 3q27 close by the TP63 locus, namely the LMS and ADULT syndromes. Here, we report on a missense TP63 gene mutation in an isolated ADULT syndrome case. This finding widens the spectrum of abnormalities to be ascribed to TP63 gene in human and emphasise on the variable roles of the different Tp63 isotypes.