Bilateral Complete Isolated Cryptophthalmos: A Case Report

Ultrasonographic Visualization of Bilaterally Fused Eyelids in a Premature Neonate

In cases of significant prematurity, neonates born with eyelid fusion can undergo spontaneous eyelid disjunction. Here, the authors present such a case, along with ultrasound findings shortly before eyelid separation. All protected patient information extracted for this report was done so in accordance with the Health Insurance Portability and Accountability Act. This report was prepared in accordance with the tenants of the Declaration of Helsinki.

[Unilateral cryptophthalmos (a clinical and morphological study)]

Cryptophthalmos is a rare ocular cup malformation, which is classified among autosomal dominant inherited diseases, but often it occurs sporadically. The pathology is characterized by the absence of eyelids or palpebral fissure or their hypoplasia, as well as by abnormal development of the eye, especially of its anterior segment. The article describes a case of total cryptophthalmos without any associated malformations, with macrophthalmos on the right eye and abortive cryptophthalmos on the left in a one-year old girl. A pathomorphological investigation of the enucleated right eyeball was carried out.

A homozygous mutation p.Arg2167Trp in FREM2 causes isolated cryptophthalmos

Cryptophthalmos (CO, MIM: 123570) is rare congenital anomalies of eyelid formation, which can occur alone or in combination with multiple congenital anomalies as part of Fraser syndrome (FS) or Manitoba Oculotrichoanal syndrome. Causal mutations have been identified for these syndromes but not in the isolated cases. Here, we described two patients from two unrelated Chinese families: one with unilateral isolated CO, while the other with unilateral CO and renal agenesis. A novel homozygous mutation (c.6499C>T: p.Arg2167Trp) and compound heterozygote mutations (c.15delG; c.6499C>T: p.Arg2167Trp) in FREM2 (NM_172862) were identified for the two patients, respectively. The deletion mutation c.15delG resulted in a frameshift and triggered the nonsense-mediated mRNA decay. For the shared missense mutation, p.Arg2167Trp altered a conserved residue and was predicted to affect protein structure by in silico analysis. Functional analysis revealed that Arg2167Trp mutant decreased its interaction with FRAS1 related extracellular matrix 1 (FREM1) and impaired the function of the FRAS1-FRAS1 related extracellular matrix 1 (FREM2)-FREM1 ternary complex required for normal embryogenesis. Furthermore, considering that mutation (c.5914C>T: p.Glu1972Lys) in FREM2 causes FS, a severe systemic disorder, we also compared these two different missense mutations. Our results showed that p.Arg2167Trp had a weaker effect in interrupting interactions between FREM2 and FREM1 than FS-associated missense mutation p.Glu1972Lys. Overall, our data demonstrate that the homozygous mutation p.Arg2167Trp in FREM2 causes isolated CO, which will facilitate our better understanding of the molecular mechanisms underlying the disease.

Loss-of-function mutations in FREM2 disrupt eye morphogenesis

Cryptophthalmos is a rare congenital disorder characterized by ocular dysplasia with eyelid malformation. Complete cryptophthalmos is characterized by the presence of continuous skin from the forehead over the eyes and onto the cheek, along with complete fusion of the eyelids. In the present study, we characterized the clinical manifestations of three patients with isolated bilateral cryptophthalmos. These patients shared the same c.6499C > T missense mutation in the FRAS1-related extracellular matrix protein 2 (FREM2) gene, while each individual presented an additional nonsense mutation in the same gene (Patient #1, c.2206C > T; Patient #2, c.5309G > A; and Patient #3, c.4063C > T). Then, we used CRISPR/Cas9 to generate mice carrying Frem2^R725X/R2156W compound heterozygous mutations, and showed that these mice recapitulated the human isolated cryptophthalmos phenotype. We detected FREM2 expression in the outer plexiform layer of the retina for the first time in the cryptophthalmic eyes, and the levels were comparable to the wild-type mice. Moreover, a set of different expressed genes that may contribute secondarily to the phenotypes were identified by performing RNA sequencing (RNA-seq) of the fetal Frem2 mutant mice. Our findings extend the spectrum of FREM2 mutations, and provide insights into opportunities for the prenatal diagnosis of isolated cryptophthalmos. Furthermore, our work highlights the importance of the FREM2 protein during the development of eyelids and the anterior segment of the eyeballs, establishes a suitable animal model for studying epithelial reopening during eyelid development and serves as a valuable reference for further mechanistic studies of the pathogenesis of isolated cryptophthalmos.

[Palpebral malformations in children]

Palpebral malformations can be isolated or associated with a craniofacial disorder. Their assessment is based on clinical examination; additional investigations are mainly done to characterize craniofacial syndromes. In case of extrapalpebral lesions or complex craniofacial pathology, genetic testing must be performed. Some isolated malformations will only need a simple follow-up; others must have specific treatment, undertaken following a precise timing, taking into account child and anatomical structures' growth and the possible consequences of the malformation on the eye and child's sight (degree of urgency). When dealing with these malformations, there are two main risks to be taken into consideration: corneal irritation due to lagophtalmos and amblyopia owing to visual axis obstruction, anisometropia or strabismus.

Congenital upper eyelid coloboma: embryologic, nomenclatorial, nosologic, etiologic, pathogenetic, epidemiologic, clinical, and management perspectives

Purpose:

To review the recent literature and describe the authors’ experience with congenital upper eyelid coloboma.

Methods:

In this review, we will summarize the embryologic and etiopathogenetic bases of congenital upper eyelid coloboma, and study the published clinical reports. We will also attempt to briefly shed some light on the rarer syndromic curiosities associated with upper eyelid coloboma.

Results:

Congenital upper eyelid colobomas are one of the few nontraumatic oculoplastic emergencies that may occasionally present in the first few days of life with a corneal ulcer and may even present with impending perforation. They can present with or without corneopalpebral adhesions, may be isolated findings or a part of a larger spectrum of congenital anomalies as in the case of Fraser syndrome or Goldenhar syndrome, or could be associated with other rare curiosities that could challenge the clinician with a huge diagnostic dilemma.

Conclusions:

Existing literature dealing with congenital colobomas of the upper eyelid is fraught with nosologic problems, confusing etiologies, and overlapping clinical features. We attempted to clarify the salient clinical features, outline the management principles, and until a time in the not-so-distant future where advances in molecular genetic testing would help redefine the etiology and the diverse clinical spectrum of genetic diseases associated with upper eyelid colobomas, we propose a simplified classification scheme based on the relation of the coloboma to the cornea, the presence or absence of systemic features, and all the syndromic and nonsyndromic associations of congenital coloboma of the upper eyelid known today.

In this review, the authors will describe the pathogenesis of upper eyelid coloboma, suggest a new simplified classification system, describe the clinical picture in detail, clarify the various syndromic associations of upper eyelid coloboma, and lay out the basic surgical principles of management.

Eyebrow loss: clinical review

Loss of eyebrow hair may come to the attention of the dermatologist as a presenting complaint or as an unexpected finding on routine physical examination. Because eyebrows serve important cosmetic and social roles, their loss can be quite distressing to patients. While eyebrow loss may be an isolated finding of no medical consequence, it may also be an initial manifestation of a systemic condition. Loss of eyebrows has numerous causes including primary dermatoses, endocrinopathies, autoimmune conditions, infections, neoplasms, trauma, exogenous agents, and genetic diseases. We present a systemic review of eyebrow loss, including an algorithm that can be used to direct the work-up of patients presenting with this condition.