To describe the petal-shaped corneal pattern in a patient with posterior amorphous corneal dystrophy. A 19-year-old male affected by Graves' disease presented corneal grey sheet-like opacities and high hyperopia. Corneal topography showed reduced k-values compatible with cornea plana and reduced corneal pachymetry. The anterior segment optical coherence tomography showed a hyperreflective band at the posterior stroma-Descemet-Endothelium layers in both eyes. Slit lamp examination with cobalt blue filter showed a corneal pattern resembling a petal in right eye; the pattern was similar but incomplete in left eye. After an exhaustive literature review conducted from October 1st to 30th, 2023, utilizing online databases like PubMed and Google Scholar, and employing keywords such as "Corneal Dystrophy," "Slit Lamp," "Cornea," and "Posterior Amorphous Corneal Dystrophy," we found no previous reports detailing the whole corneal pattern using a blue cobalt filter on the slit lamp in cases of posterior amorphous corneal dystrophy. Cobalt blue filter was an effective method for capturing the full photographic corneal pattern of the patient posterior amorphous corneal dystrophy. Corneal dystrophy (CD) is most recently defined as a collection of rare hereditary non-inflammatory disorders of abnormal deposition of substances in the cornea. CD was coined in 1890 by Arthur Groenouw and Hugo Biber, and the efforts of Ernst Fuchs, Wilhelm Uhthoff, and Yoshiharu Yoshida solidified the foundation of the understanding of these diseases. As proposed in 2015 by the International Classification of Corneal Dystrophies (IC3D), CD is sub-classified by the anatomic location affected: epithelial/subepithelial, epithelial-stromal, stromal, and endothelial dystrophies. Discoveries and unique case studies continue to broaden our understanding and classification of these diseases; therefore, it is difficult to categorize every single dystrophy solely into these four major labels.   The objective of this article is to present an overview of the evaluation and management for the most prominent and understood variants of CD. Highlights of these dystrophies will be discussed. However, further in-depth discussion on these dystrophies will be in separate StatPearls articles.  Patients with CD can be asymptomatic, but if symptoms occur, they typically experience bilateral visual acuity loss, typically in the form of irregular astigmatism. Depending on the corneal layer affected, patients may also manifest with photophobia, dry eyes, corneal edema, and recurrent corneal erosions, especially with epithelial-based CD, which causes considerable pain. Symptoms can begin at any age, depending on the diagnosis. Treatment can range from conservative measures to corneal transplantation.   CD is a significant but rare ocular disease. The genetic component of this disease is important for patients to understand, especially for affected patients involved with family planning. As we begin to understand genetics in greater detail, better evaluation and treatments for CD will come to fruition.  The objective of this article is to present an overview of the general evaluation and management for the most prominent and understood variants of CD. Highlights of these dystrophies will be covered, but the author intends to elaborate on these dystrophies separately in other StatPearls articles. The variants of CD based on their new anatomic classifications in IC3D are:  Epithelial and subepithelial dystrophies  : Epithelial basement membrane corneal dystrophy (EBMCD), also previously known as map-finger-dot dystrophy, Cogan microcystic dystrophy, and anterior basement membrane dystrophy. . Epithelial recurrent erosion dystrophies (EREDs) which includes Franceschetti corneal dystrophy, dystrophia smolandiensis, and dystrophia helsinglandica . Subepithelial mucinous corneal dystrophy (SMCD) . Meesmann corneal dystrophy (MECD) also known as juvenile epithelial corneal dystrophy . Lisch epithelial corneal dystrophy (LECD) . Gelatinous drop-like corneal dystrophy (GDLD) . Epithelial-Stromal Dystrophies (still included under epithelial and subepithelial dystrophies) : Lattice corneal dystrophy (LCD), with its subtypes: type I (TGFBI mutation) and type II (familial amyloidosis Finnish type), including LCD variants . Granular corneal dystrophy (GCD), types I and II (Avellino-type)  . Reis-Bückler’s corneal dystrophy (RBCD) . Thiel-Behnke corneal dystrophy (honeycomb dystrophy) (TBCD) . Stromal dystrophies: Macular corneal dystrophy (MCD)  . Schnyder corneal dystrophy (SCD)  . Congenital stromal corneal dystrophy (CSCD)  . Fleck corneal dystrophy (FCD)  . Posterior amorphous corneal dystrophy (PACD)  . Pre-Descemet corneal dystrophy (PDCD)  . Central cloudy dystrophy of francois (CCDF) . Endothelial Corneal Dystrophies: Fuchs endothelial corneal dystrophy (FECD)  . Posterior polymorphous corneal dystrophy (PPCD)  . Congenital hereditary endothelial dystrophy (CHED)  . X-linked endothelial corneal dystrophy (XECD) .

The purpose of this study was to report the clinical features and describe the results obtained by multimodal corneal imaging of a patient with novel chromosomal breakpoints of the 12q21.33 locus. This study was a case report and literature review. A 12-year-old girl presented with visual loss whose examination revealed a best-corrected visual acuity of 20/50 in her right eye and 20/35 in her left eye and corneal flattening and gray sheet-like opacities deep in the stroma. Anterior segment optical coherence tomography and ultrabiomicroscopy showed an evenly distributed hyperreflective line in the posterior stroma. Confocal microscopy revealed enlarged keratocytes and the presence of small reflective deposits from the pre-Descemet line to the endothelium. In addition, a 447-kb deletion that included the small leucine-rich proteoglycan-coding region in locus 12q21.33 was found. She was, therefore, diagnosed with PACD. PACD is a rare genetic disorder of the cornea characterized by gray sheet-like opacification of the posterior stroma in combination with corneal flattening. Confocal microscopy provides histologic segmentation of each corneal layer and shows the degree to which they are affected. New chromosomal breakpoints of a deletion in the small leucine-rich proteoglycan-coding region are hereby reported. PACD may be a contiguous gene syndrome, and further tests are required to identify the exact position responsible for the phenotypic variation.

Concomitant corneal ectasia and posterior lamellar corneal opacification is rare, and the genetic relationship between these two conditions is unclear. We report the genetic and clinical characterization of this phenotype in three unrelated individuals. One previously reported affected individual and two unreported, unrelated, affected individuals were recruited for the study. Subjects and unaffected relatives underwent slit lamp examination, refraction, and multi-modal imaging. Saliva samples were obtained from two of the three affected individuals, from which DNA was extracted. Sanger sequencing was performed to identify mutations in genes associated with posterior amorphous corneal dystrophy (PACD), brittle cornea syndrome (BCS), and posterior polymorphous corneal dystrophy (PPCD), while copy number variation (CNV) analysis was used to identify CNV in the PACD locus. Affected individuals demonstrated bilateral corneal steepening, stromal thinning and lamellar posterior corneal opacification. Corneal topography and tomography revealed conical or globular corneal steepening and decreased thickness. Anterior segment optical coherence tomography demonstrated hyperreflectivity of the posterior stroma in each of the affected individuals. Genetic testing did not detect a heterozygous deletion involving the PACD locus on chromosome 12 or a pathogenic mutation in the genes associated with BCS or PPCD. Corneal ectasia may be associated with posterior lamellar stromal opacification that appears consistent with PACD. However, genetic testing for PACD as well as BCS and PPCD in affected individuals fails to reveal pathogenic deletions or mutations, indicating that other genetic factors are involved.

Posterior amorphous corneal dystrophy (PACD) (OMIM 612868) is a rare autosomal dominant disorder characterized by partial or complete posterior lamellar corneal opacification, decreased corneal thickness and flattening of the corneal curvature. PACD is associated with heterozygous deletions in chromosome band 12q21.33 harboring DCN, KERA, LUM, and EPYC which encode small leucine-rich proteoglycans. We report on a 7-year-old male patient with PACD who had an interstitial deletion of 1.3 Mb in 12q21.33. His mother carried a balanced insertional translocation involving this 12q21.33 segment which was inserted into the proximal part of the long arm of one chromosome 13. The patient corroborates previous observations that PACD is a contiguous gene syndrome caused by combined haploinsufficiency of DCN, KERA, LUM, and EPYC and provides the first example of a balanced chromosome rearrangement involving 12q21.33 in an unaffected parent.

To present the clinical and cytogenetic features of a previously unreported family with posterior amorphous corneal dystrophy (PACD) associated with a heterozygous deletion of the small leucine-rich proteoglycan (SRLP) genes on chromosome 12. Clinical characterization was performed using slit lamp biomicroscopic and optical coherence tomography (OCT) imaging. Genomic DNA was collected from affected and unaffected family members, and a cytogenomic array was used to identify copy number variations (CNV) present in the PACD locus. Three members of a Guatemalan family presented with clinical characteristics consistent with PACD: bilateral posterior stromal lamellar opacification, decreased corneal curvature, and iridocorneal adhesions. OCT imaging demonstrated decreased corneal thickness and hyperreflectivity of the posterior third of the corneal stroma. CNV analysis confirmed the presumed clinical diagnosis of PACD by revealing a 0.304 Mb heterozygous deletion in the PACD locus on chromosome 12 that included the four SLRP genes (KERA, LUM, DCN, and EPYC) deleted in each of the PACD families in which CNV analysis has been reported. This is the first report of the OCT appearance of PACD and the second confirmation of a heterozygous deletion of chromosome 12q21.33 as the cause of PACD, highlighting the utility of array-based cytogenomics to confirm the suspected clinical diagnosis of PACD. As the smallest previously reported pathogenic deletion was 0.701 Mb, the 0.304-Mb deletion we report is the smallest identified to date and reduces the size of the PACD locus to 0.275 Mb.