Anterior segment mesenchymal dysgenesis

Anterior segment mesenchymal dysgenesis
Classification and external resources
OMIM	107250

Anterior segment dysgenesis (ASD) is a failure of the normal development of the tissues of the anterior segment of the eye. It leads to anomalies in the structure of the mature anterior segment, associated with an increased risk of glaucoma and corneal opacity.

Peter's (or Peters) anomaly is a specific type of mesenchymal anterior segment dysgenesis, in which there is central corneal leukoma, adhesions of the iris and cornea, and abnormalities of the posterior corneal stroma, Descemet's membrane, corneal endothelium, lens, and anterior chamber.^[1]

Pathophysiology

Several different gene mutations have been identified underlying these anomalies with the majority of ASD genes encoding transcriptional regulators. In this review, the role of the ASD genes, PITX2 and FOXC1, is considered in relation to the embryology of the anterior segment, the biochemical function of these proteins, and their role in development and disease aetiology. The emerging view is that these genes act in concert to specify a population of mesenchymal progenitor cells, mainly of neural crest origin, as they migrate anteriorly around the embryonic optic cup. These same genes then regulate mesenchymal cell differentiation to give rise to distinct anterior segment tissues. Development appears critically sensitive to gene dosage, and variation in the normal level of transcription factor activity causes a range of anterior segment anomalies. Interplay between PITX2 and FOXC1 in the development of different anterior segment tissues may partly explain the phenotypic variability and the genetic heterogeneity characteristic of ASD.

References

^ Pomella, K. M.; Wagner, H. (1998). "Unilateral Peters' anomaly complicated by a corneal tattoo". Optometry and vision science : official publication of the American Academy of Optometry 75 (9): 635–639. PMID 9778695. edit

Genetic disorder, protein biosynthesis: Transcription factor/coregulator deficiencies

(1) Basic domains	1.2: Feingold syndrome · Saethre-Chotzen syndrome 1.3: Tietz syndrome

(2) Zinc finger DNA-binding domains	2.1 (Intracellular receptor): Thyroid hormone resistance · Androgen insensitivity syndrome (PAIS, MAIS, CAIS) · Kennedy's disease · PHA1AD pseudohypoaldosteronism · Estrogen insensitivity syndrome · X-linked adrenal hypoplasia congenita · MODY 1 · Familial partial lipodystrophy 3 · SF1 XY gonadal dysgenesis 2.2: Barakat syndrome · Tricho–rhino–phalangeal syndrome 2.3: Greig cephalopolysyndactyly syndrome/Pallister-Hall syndrome · Denys–Drash syndrome · Duane-radial ray syndrome · MODY 7 · MRX 89 · Townes–Brocks syndrome · Acrocallosal syndrome · Myotonic dystrophy 2 2.5: Autoimmune polyendocrine syndrome type 1

(3) Helix-turn-helix domains	3.1: ARX (Ohtahara syndrome, Lissencephaly X2) · HLXB9 (Currarino syndrome) · HOXD13 (SPD1 Synpolydactyly) · IPF1 (MODY 4) · LMX1B (Nail–patella syndrome) · MSX1 (Tooth and nail syndrome, OFC5) · PITX2 (Axenfeld syndrome 1) · POU4F3 (DFNA15) · POU3F4 (DFNX2) · ZEB1 (Posterior polymorphous corneal dystrophy 3, Fuchs' dystrophy 3) · ZEB2 (Mowat-Wilson syndrome) 3.2: PAX2 (Papillorenal syndrome) · PAX3 (Waardenburg syndrome 1&3) · PAX4 (MODY 9) · PAX6 (Gillespie syndrome, Coloboma of optic nerve) · PAX8 (Congenital hypothyroidism 2) · PAX9 (STHAG3) 3.3: FOXC1 (Axenfeld syndrome 3, Iridogoniodysgenesis, dominant type) · FOXC2 (Lymphedema–distichiasis syndrome) · FOXE1 (Bamforth–Lazarus syndrome) · FOXE3 (Anterior segment mesenchymal dysgenesis) · FOXF1 (ACD/MPV) · FOXI1 (Enlarged vestibular aqueduct) · FOXL2 (Premature ovarian failure 3) · FOXP3 (IPEX) 3.5: IRF6 (Van der Woude syndrome, Popliteal pterygium syndrome)

(4) β-Scaffold factors with minor groove contacts	4.2: Hyperimmunoglobulin E syndrome 4.3: Holt-Oram syndrome · Li-Fraumeni syndrome · Ulnar–mammary syndrome 4.7: Campomelic dysplasia · MODY 3 · MODY 5 · SF1 (SRY XY gonadal dysgenesis, Premature ovarian failure 7) · SOX10 (Waardenburg syndrome 4c, Yemenite deaf-blind hypopigmentation syndrome) 4.11: Cleidocranial dysostosis

(0) Other transcription factors	0.6: Kabuki syndrome

Ungrouped	TCF4 (Pitt-Hopkins syndrome) · ZFP57 (TNDM1) · TP63 (Rapp–Hodgkin syndrome/Hay–Wells syndrome/Ectrodactyly–ectodermal dysplasia–cleft syndrome 3/Limb–mammary syndrome/OFC8)

Transcription coregulators	coactivator: CREBBP (Rubinstein–Taybi syndrome) corepressor: HR (Atrichia with papular lesions)

see also transcription factors B structural (perx, skel, cili, mito, nucl, sclr) · DNA/RNA/protein synthesis (drep, trfc, tscr, tltn) · membrane (icha, slcr, atpa, abct, othr) · transduction (iter, csrc, itra), trfk