microcornea

Coloboma, Microphthalmia, Albinism, and Deafness

Clinical Characteristics
Ocular Features: 

A 5 year old male has been described with uveal colobomas in microphthalmic eyes plus small corneas with a pannus, dense cataracts, translucent irides, and hypopigmentation of the skin, hair and eyes.  A brain MRI showed hypoplasia of the optic nerves and chiasm.   

A 9 month old female from another family had severe microphthalmia and small optic nerves.  The internal ocular features were not reported.

Systemic Features: 

The complete phenotype is uncertain since it is based on only two reported and unrelated individuals.  The head circumference one one patient was consistent with macrocephaly accompanied by frontal bossing, shallow orbits, preauricular pits and posteriorly rotated ears.  A skeletal survey revealed evidence for osteopetrosis.  He had a sensorineural hearing deficit said to be congenital in onset.

The other patient, a 9 month old female, belonged to another nonconsanguineous family, and had similar skeletal and craniofacial features with the addition of micrognathia and hypotonia.  Congenital neurosensory hearing loss and general lack of pigmentation were noted.

All four parents have congenital sensorineural hearing loss, blue irides and fair skin with premature graying of hair.  Four sibs in the two families have phenotypes similar to that of the parents.  Only one child, a female, had no features of the phenotype.

Genetics

This condition, so far reported only in a male and a female in unrelated families, is the result of doubly heterozygous mutations in the MITF gene (3p13).  One mutation that causes Waardenburg syndrome 2  (WS2A) (193510) is combined with a dominant-negative allele (c.952_954delAGA [p.Arg318del]) to produce the phenotype.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.

References
Article Title: 

Cataracts 34

Clinical Characteristics
Ocular Features: 

Two families with mutations in the FOXE3 associated with cataracts have been reported.  The lens opacities may be present at birth or found soon thereafter.  In 1 family with 5 affected sibs membranous cataracts were present along with corneal opacities, microcornea and nystagmus.  In another family, 7 sibs had posterior subcapsular cataracts but no other ocular findings.

Systemic Features: 

No systemic abnormalities were associated with the ocular findings.

Genetics

Homozygous mutations in the FOXE3 (1p33) gene segregated with the eye findings in the two families.  FOXE3 is a transcription gene and its mutations are responsible for a variety of ocular abnormalities.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

Surgical cataract removal may be indicated.  Amblyopia is a risk and requires rehabilitation.

References
Article Title: 

FOXE3 contributes to Peters anomaly through transcriptional regulation of an autophagy-associated protein termed DNAJB1

Khan SY, Vasanth S, Kabir F, Gottsch JD, Khan AO, Chaerkady R, Lee MC, Leitch CC, Ma Z, Laux J, Villasmil R, Khan SN, Riazuddin S, Akram J, Cole RN, Talbot CC, Pourmand N, Zaghloul NA, Hejtmancik JF, Riazuddin SA. FOXE3 contributes to Peters anomaly through transcriptional regulation of an autophagy-associated protein termed DNAJB1. Nat Commun. 2016 Apr 6;7:10953. doi: 10.1038/ncomms10953. PubMed PMID: 27218149; PubMed Central PMCID: PMC4820811.

PubMed ID: 
27218149

Basel-Vanagaite-Smirin-Yosef Syndrome

Clinical Characteristics
Ocular Features: 

The eyes appear abnormally far apart.  Ptosis, microcornea, congenital cataracts, sparse eyebrows, and strabismus are usually present.  Epicanthal folds are often seen.

Systemic Features: 

Psychomotor development is severely delayed and with delay or absence of milestones.  DTRs are often hyperactive but some infants are described as hypotonic.  Some individuals have seizures.  There may be a nevus flammeus simplex lesion on the forehead and body hair is sparse.  Cleft palate, cardiac septal defects, hypospadius, thin corpus callosum and cerebral ventricular dilation have been observed.  The upper lip may have a tented morphology with everted lower lip vermilion. A short philtrum is common. 

Genetics

A homozygous missense mutation in the MED25 gene (19q13.33) has been reported and the transmission pattern is consistent with autosomal recessive inheritance.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No known treatment has been reported.

References
Article Title: 

Homozygous MED25 mutation implicated in eye-intellectual disability syndrome

Basel-Vanagaite L, Smirin-Yosef P, Essakow JL, Tzur S, Lagovsky I, Maya I, Pasmanik-Chor M, Yeheskel A, Konen O, Orenstein N, Weisz Hubshman M, Drasinover V, Magal N, Peretz Amit G, Zalzstein Y, Zeharia A, Shohat M, Straussberg R, Monte D, Salmon-Divon M, Behar DM. Homozygous MED25 mutation implicated in eye-intellectual disability syndrome. Hum Genet. 2015 Jun;134(6):577-87.

PubMed ID: 
25792360

Kaufman Oculocerebrofacial Syndrome

Clinical Characteristics
Ocular Features: 

Alterations in the morphology of periocular structures is the most consistent ocular feature.  These include epicanthal folds, upward-slanting lid fissures, ptosis, blepharophimosis, sparse eyebrows, and telecanthus.  However, pale optic discs, iris colobomas, microcornea, strabismus, nystagmus, and hypertelorism are variably present. 

Systemic Features: 

There is both intrauterine and postnatal growth retardation.  Hypotonia is often noted along with general psychomotor delays.  Neonatal respiratory distress and laryngeal stridor may be present.  The intellectual disability can be severe.  Corpus callosum aplasia and hypoplasia have been reported.  Microcephaly and brachycephaly with delayed suture closure are features.  The face is long and narrow and the mouth is disproportionally large.  A high arched palate can be present and the pinnae are often deformed, posteriorly rotated and may be accompanied by preauricular skin tags. The teeth appear widely spaced (diastema) and the lower jaw is underdeveloped.

Genetics

Kaufman BPIDS syndrome results from homozygous or compound heterozygous mutations in the UBE3B gene (12q23).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No general treatment is available although repair of some specific malformations is possible.

References
Article Title: 

Deficiency for the ubiquitin ligase UBE3B in a blepharophimosis-ptosis-intellectual-disability syndrome

Basel-Vanagaite L, Dallapiccola B, Ramirez-Solis R, Segref A, Thiele H, Edwards A, Arends MJ, Miro X, White JK, Desir J, Abramowicz M, Dentici ML, Lepri F, Hofmann K, Har-Zahav A, Ryder E, Karp NA, Estabel J, Gerdin AK, Podrini C, Ingham NJ, Altmuller J, Nurnberg G, Frommolt P, Abdelhak S, Pasmanik-Chor M, Konen O, Kelley RI, Shohat M, Nurnberg P, Flint J, Steel KP, Hoppe T, Kubisch C, Adams DJ, Borck G. Deficiency for the ubiquitin ligase UBE3B in a blepharophimosis-ptosis-intellectual-disability syndrome. Am J Hum Genet. 2012 Dec 7;91(6):998-1010.

PubMed ID: 
23200864

An oculocerebrofacial syndrome

Kaufman RL, Rimoin DL, Prensky AL, Sly WS. An oculocerebrofacial syndrome. Birth Defects Orig Artic Ser. 1971 Feb;7(1):135-8.

PubMed ID: 
5006210

Chorioretinopathy with Microcephaly 2

Clinical Characteristics
Ocular Features: 

Microphthalmia and microcornea are seen in most individuals and one patient had unilateral clinical anophthalmia. Hyperopia and cataracts may be present. Nystagmus is common.  One patient had a corneal opacity.  The chorioretinopathy has not been described beyond evidence of the maculopathy, attenuated retinal vessels, and occasionally hyperpigmented zones.  The ERG is either not recordable or consistent with a severe rod-cone dystrophy.  Vitreous inclusions and a 'vitreoretinal dystrophy' with falciform retinal folds were noted in several patients.  A traction detachment was present in one and bilateral serous detachments were noted in another.

Systemic Features: 

Patients have mild to severe microcephaly (up to -15 SD) with psychomotor delays.  Profound intellectual disability is a consistent feature.  Physical growth is retarded and patients have shortness of stature.  Most patients are unable to sit, stand, or walk unassisted.  One patient died at 5.5 years of age while another was alive at 20 years of age.  Rare patients may have hearing loss and seizures.

Scoliosis, kyphosis, and lordosis may be seen while  other skeletal malformations seem to occur sporadically e.g., triphalangeal thumbs, brachydactyly, postaxial polydactyly, and restricted large joint motion.  

The forehead slopes markedly.  Neuroimaging shows a consistent reduction in cortex size with simple gyral folding while the cerebellum and the brain stem are also small.  Subarachnoid cysts have been noted in several patients and the corpus callosum may be short or otherwise malformed.

Genetics

Homozygous mutations in the PLK4 gene (4q28.2) segregate with this condition.  Its product localizes to centrioles and plays a central role in centriole duplication.

For a somewhat similar condition but without the sloping forhead see Chorioretinoapathy with Microcephaly 1 (251270) but resulting from homozygous mutations in TUBGCP6.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is know.

References
Article Title: 

Mutations in PLK4, encoding a master regulator of centriole biogenesis, cause microcephaly, growth failure and retinopathy

Martin CA, Ahmad I, Klingseisen A, Hussain MS, Bicknell LS, Leitch A, Nurnberg G, Toliat MR, Murray JE, Hunt D, Khan F, Ali Z, Tinschert S, Ding J, Keith C, Harley ME, Heyn P, Muller R, Hoffmann I, Daire VC, Dollfus H, Dupuis L, Bashamboo A, McElreavey K, Kariminejad A, Mendoza-Londono R, Moore AT, Saggar A, Schlechter C, Weleber R, Thiele H, Altmuller J, Hohne W, Hurles ME, Noegel AA, Baig SM, Nurnberg P, Jackson AP. Mutations in PLK4, encoding a master regulator of centriole biogenesis, cause microcephaly, growth failure and retinopathy. Nat Genet. 2014 Dec;46(12):1283-92.

PubMed ID: 
25344692

Microphthalmia, Syndromic 5

Clinical Characteristics
Ocular Features: 

One or both eyes may be small, sometimes resembling clinical anophthalmia. Other ocular anomalies such as coloboma, microcornea, cataracts, and hypoplasia or agenesis of the optic nerve have been reported.

A pigmentary retinopathy has been described.  The retinal vessels are often attenuated and sometimes sparse.  The optic nerves and chiasm are frequently absent or hypoplastic as seen on the MRI.  ERG and VEP responses are inconsistent but are generally abnormal indicating photoreceptor malfunction.  

Systemic Features: 

Patients have a variety of systemic abnormalities including pituitary dysfunction, joint laxity, hypotonia, agenesis of the corpus callosum, and seizures.  Hypothyroidism and deficiencies of growth hormone, gonadotropins, and cortisol are present in some patients.  Developmental delay and cognitive impairment are frequently present but mental functioning is normal in some patients.  The genitalia of males are often underdeveloped.  Patients are often short in stature.

Genetics

This is an autosomal dominant condition secondary to heterozygous mutations in the OTX2 gene (14q22.3).  A variety of point mutations as well as microdeletions involving the OTX2 gene have been reported.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no treatment for the syndrome but surgical and/or endocrinological treatment may be used to correct individual features.  Special education and low vision aids may be helpful in selected patients.

References
Article Title: 

Heterozygous mutations of OTX2 cause severe ocular malformations

Ragge NK, Brown AG, Poloschek CM, Lorenz B, Henderson RA, Clarke MP, Russell-Eggitt I, Fielder A, Gerrelli D, Martinez-Barbera JP, Ruddle P, Hurst J, Collin JR, Salt A, Cooper ST, Thompson PJ, Sisodiya SM, Williamson KA, Fitzpatrick DR, van Heyningen V, Hanson IM. Heterozygous mutations of OTX2 cause severe ocular malformations. Am J Hum Genet. 2005 Jun;76(6):1008-22. Apr 21. Erratum in: Am J Hum Genet. 2005 Aug;77(2):334..

PubMed ID: 
15846561

Nanophthalmos 3

Clinical Characteristics
Ocular Features: 

A six generation Chinese family has been reported in which 12 affected members had small eyes, ptosis, apparent enophthalmos, shallow anterior chambers, and small corneas.  Hyperopic refractive errors ranged from +6.00 to +11.25 (mean +8.25).  

Systemic Features: 

None reported.

Genetics

The transmission pattern for this 6 generation family strongly suggests autosomal dominant inheritance.  No mutation has been identified but the 2q11-14 locus is strongly associated with the phenotype.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Treatment has not been reported but monitoring for narrow angle glaucoma is advised.

References
Article Title: 

Familial Acorea, Microphthalmia and Cataract Syndrome

Clinical Characteristics
Ocular Features: 

The pupil is obscured or absent secondary to fibrous overgrowth.  Microcornea and microphthalmia are present.  Iridocorneal adhesions are commonly seen on ultrasonic examination and anterior chamber angles may be narrow.  The corneas are clear but thickened centrally.  Nystagmus and esotropia have been reported.

The iris is rudimentary with a poorly developed stromal pattern and sometimes eccentrically located holes.  The ultrasound may reveal remnants of degenerative lens capsules.  Axial length in infants has been measured at about 14.7 mm but increases to 17 mm in children.  In adults the axial length is about 20 mm.  Refractive errors of +20-21 diopters have been measured.  Visual acuity is poor from birth but can be improved to some extent following pupiloplasty and lens extraction.  Intraocular pressure can be normal but one patient developed an increase in the 4th decade of life.  OCT and direct visualization of the fundus in several cases revealed normal retinal architecture and anatomy.

Systemic Features: 

None reported.  Specialty examinations failed to find any hearing loss or neurological deficits.

Genetics

The single 4 generation family tree reported is consistent with autosomal dominant inheritance.  Several likely loci on chromosomes 1, 5, 8, 11, and 17 have been reported but no candidate gene has been identified. 

Other conditions in which small pupils are found are Pierson syndrome (609049) and Warburg micro syndrome (600118) but these are associated with significant systemic abnormalities.  

Congenital microcoria (156600) is an autosomal dominant disorder with mild axial myopia and goniodysgenesis resulting from an unidentified mutation on chromosome 13.  Glaucoma is a common finding as is some iris hypoplasia.  Despite some clinical similarities, this is likely a unique disorder.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Some improvement in visual acuity has been reported following lensectomy and reconstruction of the pupil.

References
Article Title: 

Cataracts, CRYAA Mutations

Clinical Characteristics
Ocular Features: 

This seems to be a clinically heterogeneous group of lens opacities all due to mutations in the crystallin gene CRYAA.  Some patients also have colobomas and may have microcornea and corneal opacities.  The lens opacities are usually bilateral but there is considerable asymmetry in their morphology.  Opacities may be nuclear, polar, cortical, sutural, embryonal, and anterior subcapsular in location.  The cataracts are often present at birth.

Systemic Features: 

Systemic disease is absent.

Genetics

A variety of mutations in the CRYAA (21q22.3) have been reported in a several ethnic groups.  Most pedigrees are consistent with autosomal dominant inheritance but autosomal recessive inheritance has been suggested in other families.

Pedigree: 
Autosomal dominant
Autosomal recessive
Treatment
Treatment Options: 

Lens extraction may be necessary.

References
Article Title: 

Meckel Syndrome

Clinical Characteristics
Ocular Features: 

The ocular phenotype is highly variable.  The globe is often malformed or may be clinically absent.  Cryptophthalmos, clinical anophthalmia, and microphthalmos with sclerocornea and microcornea have been reported.  Posterior staphylomas, retinal dysplasia, partial aniridia, cataracts, and hypoplasia or absence of the optic nerve are sometimes seen.  Some patients have incompletely formed eyes with shallow anterior chambers, angle anomalies, and a persistent tunica vasculosa with lens opacification.  Histopathology may reveal thinning of the nerve fiber layer and a paucity of retinal ganglion cells.  The retina has been described as dysplastic with foci of rosette-like structures and abundant glial cells.

Systemic Features: 

Meckel or Meckel-Gruber syndrome is a clinically and genetically heterogeneous group of disorders with severe multisystem manifestations.  The triad of cystic renal disease, polydactyly (and sometimes syndactyly), and a skull malformation (usually an encephalocele) is considered characteristic of MKS.  However, these signs are variable and only about 60% of patients have all three features.  Many patients have additional signs such as malformations of the biliary tree, cleft palate (and/or lip), sloping forehead, low-set ears, short neck, low-set ears, ambiguous genitalia, and short, bowed limb bones.  Pulmonary hypoplasia is common which, together with kidney and liver disease, is responsible for the poor prognosis of most infants. 

Many clinical abnormalities resemble those present in the Smith-Lemli-Opitz syndrome (270400) and in Joubert syndrome (213300).

Genetics

Most conditions in this group are inherited in an autosomal recessive pattern.  Mutations in 9 genes have been identified as responsible for some variant of MKS in which there is a considerable range of clinical expression.  There is significant clinical overlap with Joubert syndrome and it is not surprising that at least 5 of these mutations have been identified in both conditions.  Further nosological confusion is generated by those who consider patients with the severe, lethal phenotype to have Meckel syndrome while those with milder disease are labeled Joubert syndrome, regardless of genotype.

Rare heterozygotes have been reported with isolated features such as polydactyly.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no treatment for this syndrome.  The prognosis for life beyond infancy is poor due to the advanced dysfunction of numerous organs such as the kidney, lungs, liver and the central nervous system.

References
Article Title: 

Clinical and genetic heterogeneity in Meckel syndrome

Paavola P, Salonen R, Baumer A, Schinzel A, Boyd PA, Gould S, Meusburger H, Tenconi R, Barnicoat A, Winter R, Peltonen L. Clinical and genetic heterogeneity in Meckel syndrome. Hum Genet. 1997 Nov;101(1):88-92.

PubMed ID: 
9385376

Pages

Subscribe to RSS - microcornea