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Anterior segment dysgenesis 4(ASGD4)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: ASGD4; Iridogoniodysgenesis syndrome; Iridogoniodysgenesis type 2; Iridogoniodysgenesis, dominant type; Iris Hypoplasia; Iris hypoplasia with early onset glaucoma, autosomal dominant
Gene (location): PITX2 (4q25)
Monarch Initiative: MONDO:0007662
OMIM®: 137600


Anterior segment dysgeneses (ASGD or ASMD) are a heterogeneous group of developmental disorders affecting the anterior segment of the eye, including the cornea, iris, lens, trabecular meshwork, and Schlemm canal. The clinical features of ASGD include iris hypoplasia, an enlarged or reduced corneal diameter, corneal vascularization and opacity, posterior embryotoxon, corectopia, polycoria, an abnormal iridocorneal angle, ectopia lentis, and anterior synechiae between the iris and posterior corneal surface (summary by Cheong et al., 2016). Anterior segment dysgenesis is sometimes divided into subtypes including aniridia (see 106210), Axenfeld and Rieger anomalies, iridogoniodysgenesis, Peters anomaly, and posterior embryotoxon (Gould and John, 2002). Patients with ASGD4 have been reported with iridogoniodysgenesis or Peters anomaly subtypes. Iridogoniodysgenesis, which is characterized by iris hypoplasia, goniodysgenesis, and juvenile glaucoma, is the result of aberrant migration or terminal induction of the neural crest cells involved in the formation of the anterior segment of the eye (summary by Mears et al., 1996). Peters anomaly consists of a central corneal leukoma, absence of the posterior corneal stroma and Descemet membrane, and a variable degree of iris and lenticular attachments to the central aspect of the posterior cornea (Peters, 1906). [from OMIM]

Additional description

From MedlinePlus Genetics
Nearly half of the individuals affected with Peters anomaly have low vision early in life and about a quarter are legally blind. Due to a lack of visual stimulation, some individuals develop "lazy eye" (amblyopia). Peters anomaly is often associated with other eye problems, such as increased pressure within the eye (glaucoma), clouding of the lens (cataract), and unusually small eyeballs (microphthalmia). In most cases, Peters anomaly is bilateral, which means that it affects both eyes, although the level of vision impairment may be different in each eye. These individuals may have eyes that do not point in the same direction (strabismus). In some people with Peters anomaly, corneal clouding improves over time leading to improved vision.

There are two types of Peters anomaly, which are distinguished by their signs and symptoms. Peters anomaly type I is characterized by an incomplete separation of the cornea and iris and mild to moderate corneal opacity. Type II is characterized by an incomplete separation of the cornea and lens and severe corneal opacity that may involve the entire cornea.

Peters anomaly is characterized by eye problems that occur in an area at the front part of the eye known as the anterior segment. The anterior segment consists of structures including the lens, the colored part (iris) of the eye, and the clear covering of the eye (cornea). During development of the eye, the elements of the anterior segment form separate structures. However, in Peters anomaly, development of the anterior segment is abnormal, leading to incomplete separation of the cornea from the iris or the lens. As a result, the cornea is cloudy (opaque), which causes blurred vision. The opaque area (opacity) of the cornea varies in size and intensity from a small, faint streak to a large, white cloudy area that covers the front surface of the eye. Additionally, the location of the opacity varies; the cloudiness may be at the center of the cornea or off-center. Large, centrally located opacities tend to cause poorer vision than smaller, off-center ones.  https://medlineplus.gov/genetics/condition/peters-anomaly

Clinical features

From HPO
Abnormality of the dentition
MedGen UID:
Concept ID:
Any abnormality of the teeth.
Abnormal facial shape
MedGen UID:
Concept ID:
An abnormal morphology (form) of the face or its components.
MedGen UID:
Concept ID:
Disease or Syndrome
Glaucoma refers loss of retinal ganglion cells in a characteristic pattern of optic neuropathy usually associated with increased intraocular pressure.
Iris hypopigmentation
MedGen UID:
Concept ID:
An abnormal reduction in the amount of pigmentation of the iris.
Hypoplastic iris stroma
MedGen UID:
Concept ID:
Underdevelopment of the stroma of iris.

Professional guidelines


Fariña R, Lolas J, Moreno E, Alister JP, Uribe MF, Pantoja R, Valladares S, Arrué C
J Craniofac Surg 2022 Mar-Apr 01;33(2):496-501. doi: 10.1097/SCS.0000000000007973. PMID: 34261964
Lenassi E, Clayton-Smith J, Douzgou S, Ramsden SC, Ingram S, Hall G, Hardcastle CL, Fletcher TA, Taylor RL, Ellingford JM, Newman WD, Fenerty C, Sharma V, Lloyd IC, Biswas S, Ashworth JL, Black GC, Sergouniotis PI
Genet Med 2020 Apr;22(4):745-751. Epub 2019 Dec 18 doi: 10.1038/s41436-019-0722-8. PMID: 31848469Free PMC Article
Plaisancié J, Ragge NK, Dollfus H, Kaplan J, Lehalle D, Francannet C, Morin G, Colineaux H, Calvas P, Chassaing N
Clin Genet 2018 Apr;93(4):837-845. doi: 10.1111/cge.13177. PMID: 29136273

Recent clinical studies


Weiss AH, Kousseff BG, Ross EA, Longbottom J
Arch Ophthalmol 1989 Nov;107(11):1619-24. doi: 10.1001/archopht.1989.01070020697031. PMID: 2818283

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