iris coloboma

Joint Laxity, Short Stature, and Myopia

Clinical Characteristics
Ocular Features: 

Three of four brothers in one family had high myopia and two had retinal detachments as well as iris and chorioretinal colobomas.  In a second family with five sibs a teenage female was reported to have glaucoma and vision of legal blindness.  She and one brother had high myopia as well (parameters not reported).

Systemic Features: 

In one consanguineous family a brother and sister had multiple large joint dislocations including elbows, hips, knees and ankles.  The sister exhibited severe kyphoscoliosis while her brother had only mild kyphosis.  A single individual in each of the two sibships had hearing loss.

Three brothers in another consanguineous family had joint laxity and mild pectus carinatum.

Short stature was noted in all 5 affected individuals.  Cognitive development was reported as normal.

Genetics

Five individuals from 2 consanguineous Saudi sibships have been reported.  Homozygous mutations in the GZF1 gene (20p11.21) segregated as expected for an autosomal recessive disorder.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment has been reported.   Retinal detachment surgery and joint dislocation reduction should be considered in appropriate individuals.

References
Article Title: 

GZF1 Mutations Expand the Genetic Heterogeneity of Larsen Syndrome

Patel N, Shamseldin HE, Sakati N, Khan AO, Softa A, Al-Fadhli FM, Hashem M, Abdulwahab FM, Alshidi T, Alomar R, Alobeid E, Wakil SM, Colak D, Alkuraya FS. GZF1 Mutations Expand the Genetic Heterogeneity of Larsen Syndrome. Am J Hum Genet. 2017 May 4;100(5):831-836.

PubMed ID: 
28475863

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

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: 

Rubinstein-Taybi Syndrome 1

Clinical Characteristics
Ocular Features: 

There is considerable clinical heterogeneity in this disorder.  Few patients have all of the clinical features and there is much variation in the severity of these.  Almost all segments of the eye can be involved.  The lashes are often lush and the eyebrows may be highly arched and bushy.  Lid fissures are often downward slanting (88%).  Congenital glaucoma, nystagmus, cataracts, lacrimal duct obstruction (37%), ptosis (29%), colobomas and numerous corneal abnormalities including keratoglobus, sclerocornea, and megalocornea have been reported.  Abnormal VEP waveforms and cone and cone-rod dysfunction have been found in the majority (78%) of patients tested.  Retinal pigmentary changes have been seen in some patients.  Refractive errors (usually myopia) occur in 56% of patients.  Visual acuities vary widely but about 20% of patients are visually handicapped.

Fluorescein angiography in a single patient revealed generalized vascular attenuation and extensive peripheral avascularity.  The AV transit time was prolonged with delayed venous filling and late small vessel leakage. 

Systemic Features: 

The facial features are reported to be characteristic but there are few distinctive signs.  The face is often broad and round, the nose is beaked, the mouth is small, and the lower lip appears to pout and protrudes beyond a short upper lip.  Smiles have been described as 'grimacing'.  It is common for the columella to protrude beyond the alae nasi.  The palate is narrow and highly arched and the laryngeal walls collapse easily which may lead to feeding problems and respiratory difficulties.  The ears may be rotated posteriorly.  The anterior hairline can appear low.

Among the more distinctive signs are the broad thumbs and great toes which are often deviated medially.  However, the distal phalanges of all fingers may be broad as well.  Bone fractures are common and patellar dislocations can be present as seen in the first two decades of life.  Hypotonia is a feature.  Numerous dental anomalies have been reported including crowded teeth, enamel hypoplasia, crossbite, and abnormal numbers of teeth.

Developmental delays are common.  Infancy and childhood milestones are often delayed.  Many patients have cognitive delays and some are mildly retarded.  Postnatal growth is subnormal and obesity is common.  A third of patients have a cardiac abnormality including septal defects, valvular defects, coarctation of the aorta, pulmonic stenosis, and patent ductus arteriosus.  Renal abnormalities occur frequently and almost all males have undescended testes.  Patients are at increased risk of tumors, both malignant and benign, many of which occur in the central nervous system.  Other problems are constipation and hearing loss.

Genetics

Evidence points to an autosomal dominant mode of inheritance secondary to mutations in CREBBP (16p13.3) but there is some genetic heterogeneity as mutations in EP300 (22q13) have been associated with a similar disease (see Rubinstein-Taybi Syndrome 2; 613684).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Treatment is directed at specific clinical features such as glaucoma and strabismus.  Special education and vocational training may be helpful.  Hearing loss may respond to standard treatment.  Fractures and dislocations should receive prompt attention.  Cardiac anomalies may require surgical correction.

References
Article Title: 

Focal Dermal Hypoplasia

Clinical Characteristics
Ocular Features: 

Features have considerable heterogeneity and few patients have all of them.  Some ocular abnormalities are found in 40% of patients.  Microphthalmia is common and many patients (30%) have colobomas of the iris and choroid.  Some patients have dislocated lenses.  Distinctive peripheral corneal lesions consisting of discrete vascularized subepithelial opacities have been described.  Occasional patients have conjunctival or lid margin papillomas.  Strabismus and nystagmus are common.

Systemic Features: 

This disorder has a wide variety of clinical features and many occur in only a few patients.  The skin has focal areas of hypoplasia with hypopigmentation, often appearing in a streak or linear pattern.  These areas may be present at birth and contain bullae or urticarial lesions with signs of inflammation.  Telangiectases and herniated fat may appear in these areas.   Oral, esophageal, and laryngeal fibrovascular papillomas occur but they may also be seen in the perineal, vulvar, and perianal areas.  These may be large, friable, and recurrent.  The teeth erupt late and are usually hypoplastic.  The nails are often dysplastic and the hands and feet may be 'split' with syndactyly of the third and fourth fingers giving a 'lobster claw' appearance.  Polydactyly may be present.  Most have thin 'protruding' ears.  A variety of skeletal anomalies have been reported including absence of metatarsals and metacarpals.  A considerable number of patients have mild to moderate mental deficits.  Severely affected females may die in infancy.

Genetics

This is considered an X-linked dominant disorder with lethality in males.  However, numerous affected males (>30) and rare instances of father-to-daughter transmission have been reported and it has been suggested that half-chromatid mutations or postzygotic somatic mosaicism in these males might be responsible.  Mutations in the PORCN gene (Xp11.23) have been associated with FDH.

Pedigree: 
X-linked dominant, mother affected
Treatment
Treatment Options: 

Surgery may be required for the papillomas if they are obstructive.

References
Article Title: 
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