clinical anophthalmia

Bosma Arhinia Microphthalmia Syndrome

Clinical Characteristics
Ocular Features: 

Microphthalmia or clinical anophthalmia are usually present.  Iris colobomas are frequent features.  Occluded or absent nasolacrimal ducts have been reported.

Systemic Features: 

Arhina with anosmia is the most striking feature but it is usually accompanied by midface hypoplasia, a highly arched (or cleft) palate, and preauricular pits.  The nasal bones along with the cribriform plate, and other septal structures may be missing.  Maxillary and paranasal sinuses, together with the olfactory bulbs are often absent.  Intelligence is usually normal.

Choanal atresia is often present.  Hypogonadotropic hypogonadism with micropenis and cryptorchidism is an important feature in males.  Females may experience pubertal delay with menarche anomalies.  

Genetics

Heterozygous mutations in the SMCHD1 gene (18p11) are responsible for this disorder.  There is considerable clinical heterogeneity with many carriers having only minor manifestations.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

No treatment for the general disorder has been described.

References
Article Title: 

De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development

Gordon CT, Xue S, Yigit G, Filali H, Chen K, Rosin N, Yoshiura KI, Oufadem M, Beck TJ, McGowan R, Magee AC, Altmuller J, Dion C, Thiele H, Gurzau AD, Nurnberg P, Meschede D, Muhlbauer W, Okamoto N, Varghese V, Irving R, Sigaudy S, Williams D, Ahmed SF, Bonnard C, Kong MK, Ratbi I, Fejjal N, Fikri M, Elalaoui SC, Reigstad H, Bole-Feysot C, Nitschke P, Ragge N, Levy N, Tuncbilek G, Teo AS, Cunningham ML, Sefiani A, Kayserili H, Murphy JM, Chatdokmaiprai C, Hillmer AM, Wattanasirichaigoon D, Lyonnet S, Magdinier F, Javed A, Blewitt ME, Amiel J, Wollnik B, Reversade B. De novo mutations in SMCHD1 cause Bosma arhinia microphthalmia syndrome and abrogate nasal development. Nat Genet. 2017 Feb;49(2):249-255.

PubMed ID: 
28067911

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

Microphthalmia, Syndromic 6

Clinical Characteristics
Ocular Features: 

Ultrasound evaluation reveals globe size to vary widely from extremely small (6 mm) to normal axial length. Clinical anophthalmia is often diagnosed.  Both anophthalmia and microphthalmia may exist in the same individual. True anophthalmia has been confirmed in some patients in which no ocular tissue was detectable with ultrasound examination.  In such cases the optic nerves and chiasm are often missing as well.  Iris colobomas are common and these may extend posteriorly.  Myopia is sometimes present.

The ERG reveals generalized rod and cone dysfunction in some eyes, but may be normal in others. In many eyes the ERG is nonrecordable. Cataracts are frequently present.

Systemic Features: 

Digital and hand anomalies are common.  The hands are often described as broad and the thumbs may be low-placed.  The nails can appear dysplastic and postaxial polydactyly is often present.  Mild webbing of the fingers has been reported as well.  Microcephaly and the cranium can be misshapen. A high arched palate is often present and clefting has also been noted.  Micrognathia may be present. Some evidence of physical growth retardation is often evident.

Pituitary hypoplasia is not uncommon and may be associated with hypothyroidism and cryptorchidism with hypospadias, and a small or bifid scrotum.

The brain anomalies vary considerably.  Many patients have mild to moderate developmental delays with some learning difficulties. Sensorineural hearing loss is often present. Hypoplasia of the vermis, thinning of the corpus callosum, widening of the lateral ventricles, and occasional generalized cortical atrophy, at least in older individuals, have been described.

Genetics

This is an autosomal dominant condition caused by a point mutation in BMP4 (bone morphogenetic protein-4) (14q22-q23).  A number of chromosomal deletions involving this gene have also been identified in individuals who have this syndrome but since contiguous genes such as OTX2 and SIX6 may also be involved, the phenotype is more likely to be associated with other anomalies including genital hypoplasia, pituitary hypoplasia, absence of the optic nerves and/or chiasm, developmental delay, digital malformations, and cerebellar dysplasia.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Cataracts can be removed in selected individuals with potential visual function.  Socket prostheses should be considered in anophthalmia and extreme microphthalmia.  Low vision devices, Braille, and mobility training should be initiated early when appropriate.  Hearing evaluations should be done as soon as practical.

Learning specialists and special education facilities should be available for selected patients.  Polydactyly, syndactyly, skull, and cleft palate repairs may be indicated.

References
Article Title: 

Mutations in BMP4 cause eye, brain, and digit developmental anomalies: overlap between the BMP4 and hedgehog signaling pathways

Bakrania P, Efthymiou M, Klein JC, Salt A, Bunyan DJ, Wyatt A, Ponting CP, Martin A, Williams S, Lindley V, Gilmore J, Restori M, Robson AG, Neveu MM, Holder GE, Collin JR, Robinson DO, Farndon P, Johansen-Berg H, Gerrelli D, Ragge NK. Mutations in BMP4 cause eye, brain, and digit developmental anomalies: overlap between the BMP4 and hedgehog signaling pathways. Am J Hum Genet. 2008 Feb;82(2):304-19.

PubMed ID: 
18252212

Microphthalmia and Anophthalmia, ALDH1A3 Associated

Clinical Characteristics
Ocular Features: 

Patients have a variety of ocular malformations including microphthalmia and clinical anophthalmia.  Some have orbital cysts. Imaging may reveal hypoplastic optic nerves and chiasms.

Systemic Features: 

Both cardiac (pulmonary stenosis and septal defects) and neurological deficits (autism spectrum disorders and 'intellectual disability') have been reported.  Birth weight and head circumference are often low.  However, brain imaging has revealed no consistent malformations.

Genetics

This is an autosomal recessive disorder resulting from homozygous mutations in the gene ALDH1A3 (15q26.3) which encodes the enzyme retinaldehyde dehydrogenase.  Mutations in ALDH1A3 impair the enzymatic oxidation of retinaldehyde important to the synthesis of retinoic acid, a key signaling molecule in eye development. 

However, mutations in other genes important to ocular development such as GJA3 and SOX2 (a transcription factor) may result in a similar phenotype.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment for the ocular problems is available.

References
Article Title: 

ALDH1A3 Mutations Cause Recessive Anophthalmia and Microphthalmia

Fares-Taie L, Gerber S, Chassaing N, Clayton-Smith J, Hanein S, Silva E, Serey M, Serre V, G?(c)rard X, Baumann C, Plessis G, Demeer B, Br?(c)tillon L, Bole C, Nitschke P, Munnich A, Lyonnet S, Calvas P, Kaplan J, Ragge N, Rozet JM. ALDH1A3 Mutations Cause Recessive Anophthalmia and Microphthalmia. Am J Hum Genet. 2013 Feb 7;92(2):265-70.

PubMed ID: 
23312594

Microphthalmia, Syndromic 3

Clinical Characteristics
Ocular Features: 

Microphthalmia or clinical anophthalmia is the major ocular malformation in this disorder but optic nerve hypoplasia or even aplasia may also be present.  Colobomas and congenital cataracts may be seen.

Systemic Features: 

Esophageal atresia and sometimes tracheoesophageal fistula sometimes coexist. The ears can be low-set and malformed and sensorineural hearing loss is often present.  Facial palsy has been reported.  The penis may be small and combined with cryptorchidism while physical growth retardation is common.  Other less common malformations include cleft palate, vertebral anomalies, cardiac anomalies, body asymmetry, and microcephaly.  A few patients have had radiologically evident CNS malformations such as dilated ventricles, hippocampal hypoplasia, abnormal white matter, and holoprosencephaly.  However, intellectual development and function have been normal in other patients.

Genetics

This is an autosomal dominant disorder secondary to heterozygous mutations in the SOX2 gene (3q26.33).  Chromosomal aberrations involving this region of chromosome 3 have also been found.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Depending upon the severity of malformations, life expectancy can be normal but some patients have died in the neonatal period.  Certain defects such as those of the heart, palate and esophagus can be surgically repaired.  Hearing device can be helpful but no treatment is available for the eyeball malformations.

References
Article Title: 
Subscribe to RSS - clinical anophthalmia