Peters Plus syndrome: a recognizable clinical entity

Peters anomaly: An overview

Peters anomaly (PA) is a rare, often bilateral, congenital corneal opacity, usually with a sporadic inheritance pattern, characterized by corneal opacities and irido-corneal or lenticular-corneal adhesions with a defect in the Descemet's membrane, occurring due to anterior segment dysgenesis during fetal development. Due to other ocular and systemic comorbidities, a team comprising pediatric cornea, glaucoma, and strabismus specialists in addition to a pediatrician and geneticist is necessary for the appropriate management of these children. Since the outcome of pediatric penetrating keratoplasty is variable and has a higher chance of failure when accompanied by additional procedures, such as lensectomy and vitrectomy, minimally invasive alternatives are increasingly being offered to these patients. Of note is the recently reported novel procedure: selective endothelialectomy for PA, which avoids the need for a corneal transplant and results in gradual clearing of the corneal opacity over time. In this overview, we aimed to describe the etiology, classification, pathophysiology, histopathology, clinical features, and management of PA.

Peters Anomaly: Novel Non-Invasive Alternatives to Penetrating Keratoplasty

BACKGROUND

Peters' anomaly (PA) is the most commonly encountered congenital corneal opacity (CCO) and displays a wide phenotypical range. The relatively recent adoption of high-quality anterior segment imaging in the form of high-frequency ultrasound biomicroscopy and anterior segment optical coherence tomography has aided in the accurate diagnosis of CCOs, facilitated distinction of PA from "pseudo-Peters' anomaly," and aided in prognostication and surgical risk stratification in PA. While the definitive management of PA, especially the more severe forms, is penetrating keratoplasty (PK), long-term success rates have overall been disappointing. This spurred the development of more non-invasive procedures, such as optical iridectomy and the more recently described selective endothelial removal, which represent viable alternatives to PK, at least in the less severe phenotypes of PA.

METHODS

Literature searches for the components of this review were performed using PubMed, in September 2021. The following keywords and their iterations were employed for the searches: "Peters' anomaly," "anterior segment dysgenesis," "kerato-irido-lenticular dysgenesis," "congenital corneal opacities." These were entered into the PubMed search engine, revealing 2852 related articles. The inclusion criteria included publications in the English language, specific to Peters' anomaly. Fifty-five studies that were published as systematic reviews or as nonrandomized comparative studies (cohort or case series) on the topic of Peters' anomaly were finally selected for this review.

RESULTS

This review provides a summary of Peters' anomaly in the context of advances in diagnosis, classification, and genotype-phenotype correlation of congenital corneal opacities, with a focus on penetrating keratoplasty, its outcomes, and non-invasive surgical options. While conservative therapies such as spontaneous clearing, mydriatic eye drops, and optical iridectomy may have variable success in milder variants of PA, penetrating keratoplasty in these eyes is fraught with several challenges and typically results in poor long-term functional outcomes. The management strategy depends on several variables such as phenotypical severity of PA, laterality, age at presentation, and capacity to adhere to the follow-up schedule. Notwithstanding the choice of treatment, it is essential that early and aggressive amblyopia therapy, a thorough systemic examination, and appropriate referral are undertaken for all patients of PA.

CONCLUSION

Peters' anomaly has seen recent advances in diagnosis, but treatment options remain limited. Focus directed towards less-invasive alternatives to keratoplasty may yield better functional outcomes.

Peter's anomaly-A homeotic gene disorder

Peter's anomaly is a rare form of congenital anterior segment dysgenesis of the eye. Varying degrees of central corneal opacity and lenticulo-corneal or irido-corneal synechiae are the key hallmarks. The association of Peter's anomaly along with short stature, rhizomelia, broad short hands or brachydactyly, with facial dysmorphism, cleft lip, cleft palate, genitourinary and cardiovascular anomalies is a distinct and is often termed Peter's plus syndrome. Early detection is imperative to prevent sensory deprivation amblyopia. Glaucoma can be present at initial diagnosis or at any stage later, but treatment can be difficult. For the dense leukoma, corneal graft may be needed but visual prognosis is poor. Research focussing on gene editing and regenerative medicine using native corneal endothelial cells is ongoing.

Fetal central nervous system anomalies: When should we offer exome sequencing?

OBJECTIVE

To investigate the detection of pathogenic variants using exome sequencing in an international cohort of fetuses with central nervous system (CNS) anomalies.

METHODS

We reviewed trio exome sequencing (ES) results for two previously reported unselected cohorts (Prenatal Assessment of Genomes and Exomes (PAGE) and CUIMC) to identify fetuses with CNS anomalies with unremarkable karyotypes and chromosomal microarrays. Variants were classified according to ACMG guidelines and association of pathogenic variants with specific types of CNS anomalies explored.

RESULTS

ES was performed in 268 pregnancies with a CNS anomaly identified using prenatal ultrasound . Of those with an isolated, single, CNS anomaly, 7/97 (7.2%) had a likely pathogenic/pathogenic (LP/P) variant. This includes 3/23 (13%) fetuses with isolated mild ventriculomegaly and 3/10 (30%) fetuses with isolated agenesis of the corpus callosum. Where there were multiple anomalies within the CNS, 12/63 (19%) had LP/P variants. Of the 108 cases with CNS and other organ system anomalies, 18 (16.7%) had LP/P findings.

CONCLUSION

ES is an important tool in the prenatal evaluation of fetuses with any CNS anomaly. The rate of LP/P variants tends to be highest in fetuses with multiple CNS anomalies and multisystem anomalies, however, ES may also be of benefit for isolated CNS anomalies.

Updates on congenital lacrimal drainage anomalies and their association with syndromes and systemic disorders: A major review

BACKGROUND

To review and update the syndromic and non-syndromic systemic associations of congenital lacrimal drainage anomalies.

METHODS

The authors performed a PubMed search of all articles published in English on congenital lacrimal drainage anomalies (CLDA). The current review provides an update from January 2017 to August 2020 on all CLDA associated with clinical syndromes or non-syndromic systemic disorders. The update intends to appraise the readers on all papers that were published in the interim 3-year period since the publication of the previous major review by authors (1933-2016). Patients with specific syndromes or systemic disorders were then reviewed. Pertinent cross-references from each of the short-listed articles were also included. Data reviewed include syndromic descriptions, systemic details, demographics, lacrimal presentations, management, and outcomes.

RESULTS

There have been significant new updates. Eleven new syndromes have been added to the list of syndromic associations, of which three were suspects. Among the new syndromic associations, three (PHACE, Williams-Beuren, and Peter's plus syndromes) described CLDA details in depth. Several new non-syndromic systemic conditions with associated CLDA also came to light, the foremost amongst them being proboscis lateralis, diprosopus dirrhinus, cerebral palsy, and NGLY-1 related disorders. Although familial presentations have been reported, the inheritance patterns are unclear for most anomalies. Surgical challenges in these patients are distinct, and a thorough pre-operative assessment, including detailed imaging when indicated, may facilitate good outcomes. Two updated tables reflecting the summary of syndromic and non-syndromic systemic associations are provided to capture the details at a glance.

CONCLUSION

It is not very uncommon to find CLDA in syndromic or non-syndromic systemic disorders. Diagnosis of a craniofacial syndrome should prompt the physician to look out for CLDA. Similarly, a diagnosis of multiple CLDA should alert the examiner for the possible presence of associated systemic anomalies.