Chiasmal misrouting and foveal hypoplasia without albinism.

BACKGROUND/AIMS: To present the ophthalmological and electrophysiological characteristics of three darkly pigmented, female patients with misrouting and foveal hypoplasia. One of the patients had primary ciliary dyskinesia and situs inversus totalis (Kartagener syndrome). METHODS: Fundus photographs were taken and the angles at which the main temporal arterial branches leave the optic nerve head (ONH) were analysed. Optical coherence tomography (OCT) was performed through the presumed foveal region. Pattern onset visually evoked potentials (VEPs) (check sizes 60', 40/400 ms) were recorded and the chiasmal coefficient was calculated to detect misrouting. RESULTS: Fundus photography showed normally pigmented fundi with absence of the usual foveal hyperpigmentation, foveal avascular zone, and macular and foveal reflexes. On OCT no foveal pit was found. The VEP recordings showed the largest positive CI component over the right hemisphere for the left eye, and over the left hemisphere for the right eye, with the CI almost absent over the ipsilateral hemispheres. The differential derivations showed opposite polarity for the recordings of the two eyes. The chiasmal coefficients of all three patients were significantly indicative of misrouting (-0.99, -0.91, and -0.99, respectively). CONCLUSION: Based on the investigations in these patients the authors propose the hypothesis that foveal hypoplasia and misrouting exist as a distinct entity, and do not comprise the exclusive hallmark of albinism. The findings suggest that misrouting may exert a retrograde influence on foveal development.

Thiamine-responsive megaloblastic anemia syndrome (TRMA) with cone-rod dystrophy.

Thiamine-responsive megaloblastic anemia (TRMA) is an autosomal recessive disease in which the active thiamine uptake into cells is disturbed. The molecular basis underlying the disorder has been related to mutations in the gene SLC19A2 on chromosome 1q23.3 that encodes a functional thiamine transporter. The protein is predicted to have 12 transmembrane domains. TRMA is characterized by sensorineural deafness, diabetes mellitus, megaloblastic anemia, and cardiomyopathy. Optic nerve atrophy and retinal dystrophy have been reported in a small number of patients. We report a 15-year-old girl with TRMA and cone-rod dystrophy and confirm that retinal dystrophy may form part of the syndrome. Differential diagnosis of syndromes with deafness, diabetes mellitus, and optic nerve atrophy or retinal dystrophy are discussed. The authors suggest that ERG be performed in all patients with TRMA.

Microcephaly with chorioretinopathy. A report of two dominant families and three sporadic cases.

This is a report of seven new cases of microcephaly with chorioretinopathy. Three cases were sporadic and four were dominant: a father and son, and a father and daughter. Their ophthalmological, neurological, and systemic findings are discussed as are the genetics of the syndrome. Chorioretinopathy with characteristic punched-out lesions was observed in both entities. Body height emerges as a possible distinguishing feature between the dominant and recessive forms. In addition, locomotor disturbances are more frequently seen in patients with the recessive form.

Isolated Norrie disease in a female caused by a balanced translocation t(X,6).

This is the second report of Norrie disease in a female patient with a de-novo balanced translocation t(X,6) with breakpoint at the location of the Norrie gene. At the age of 3 months, a girl was referred for suspected congenital glaucoma. The right eye was microphthalmic and ultrasonography was compatible with persistent hyperplasia of the primary vitreous. The left eye was also microphthalmic. The left cornea was larger than the right. The anterior chamber was virtual and leukocoria was evident. The eye felt hard digitally. Ultrasonography indicated an organized retinal detachment. The pathologic findings are reported and are compatible with Norrie disease.

Neurological disorders in members of families with Leber's hereditary optic neuropathy (LHON) caused by different mitochondrial mutations.

Neurological abnormalities have been occasionally associated with Leber's hereditary optic neuropathy (LHON). We describe four patients with spastic dystonia from two of our 35 LHON families. Magnetic resonance imaging revealed signal alterations of globus pallidus, putamen, internal capsula, and substantia nigra. Neuropathological findings in one of the patients with dystonia are described. Each of the dystonia families carries a different mtDNA mutation; one at np 3460 and one at np 11778. Periventricular multiple sclerosis-like white matter lesions were observed in one individual from a third family with the mtDNA 3460 mutation. Neurological disorders are probably underestimated in association with LHON.

Biometry in X linked megalocornea: pathognomonic findings.

Biometric study in a series of 11 affected males provides characteristic findings. The patients present with a large cornea with short radius, very deep anterior chamber depth (AC depth) exceeding the normal mean value of plus 2 SD, and a short vitreous length. Calculation of the postlimbal depth, a method applied in this study to obtain information about positioning of the iris and the lens, reveals a posterior positioning of the iris and lens. The posterior positioning of the iris and lens was proved to occur at the expense of the vitreous. The importance of biometric data for diagnosis and for differential diagnosis in primary infantile glaucoma and other diseases with megalocornea is discussed.

X linked progressive cone dystrophy. Localisation of the gene locus to Xp21-p11.1 by linkage analysis.

Six affected males, three female carriers, and two possible carriers were evaluated from a three generation pedigree with X linked progressive cone dystrophy. The affected males presented with progressive decrease of visual acuity, impairment of colour vision, and deterioration of electroretinogram, which ranged from absent response to red light in all young patients to abnormal cone-rod responses in the elderly ones. In most affected males dark adaptation curves were monophasic and the electro-oculogram values were reduced. While some obligate carriers showed functional anomalies, they all had reduced electroretinogram response to red light. The a1/aT ratio for 1 joule white light was an appropriate indicator for carrier state. The family was studied with seven DNA markers from the proximal part of the short arm of the human X chromosome. So far, significant linkage has been found between three DNA markers and COD1, which assigns the progressive cone dystrophy gene (COD1) in this family to Xp21-p11.1. Differential diagnosis with congenital cone dystrophies is discussed.

Retinal manifestations in fibromuscular dysplasia.

Fibromuscular dysplasia of the arteries (FMD) is a segmental angiopathy which may produce obstruction of the carotid, cerebral, renal, mesenteric, coronary or iliac arteries. Except for lesions related to arterial hypertension, retinal manifestations have not yet been reported. This paper describes the case of a 10-year-old boy with progressive deafness, a history of an unexplained stroke and progressive occlusions of the retinal arterioles in the fundus periphery. This resulted in retinal neovascularization and recurrent retinal and vitreous hemorrhages. Despite repeated photo- and cryocoagulation the eyes progressed to a tractional retinal detachment which was successfully treated by vitrectomy and scleral buckling. The diagnosis of FMD was made on the basis of a histopathological examination of a temporal artery biopsy. The child also presented an asymptomatic but severe aneurysmal dilatation of the aorta and CT scan and MRI showed dilated cerebral arteries. The father of our patient had died at the age of 27 years either from myocardial infarction or rupture of a dissecting aortic aneurysm. He was highly myopic and had lost one eye from retinal detachment. The younger brother of our patient also presents aneurysmal dilatation of the aorta and tortuous cerebral vessels. Ocular examination is still normal. The findings in this family are compatible with an autosomal dominant inheritance with variable expression.

Hereditary ectopia lentis. A series of 10 cases of ectopia lentis et pupillae.

Ectopia lentis may belong to different syndromes, Marfan syndrome and homocystinuria being the most common. Hereditary ectopia lentis may also be an isolated ocular condition. Inheritance of simple ectopia lentis is autosomal dominant (AD) or autosomal recessive (AR). In ectopia lentis et pupillae the pupils are characteristically oval and slit shaped. Inheritance is AR. We will present our series of 10 cases.

Lenticonus.

Lenticonus is a bulging of the lens capsule and the underlying cortex. The diagnosis of lenticonus is essentially a clinical diagnosis which is made by biomicroscopic examination. According to the localization of the conus a distinction is made between lenticonus anterior and lenticonus posterior. Whereas lenticonus anterior is part of the Alport syndrome, lenticonus posterior is not associated with systemic disease. A case report of each of both types is presented and the clinical presentation, the aetiology, the pathogenesis and the treatment are discussed.

The Hallermann-Streiff syndrome.

The Hallermann-Streiff syndrome is characterised by systemic and ocular anomalies, including congenital cataract and microphthalmia. A case is presented and the differential diagnosis discussed.

Congenital Marfan syndrome with contractures. A clinicopathological report.

Children with CMC present with blue sclerae, megalocornea, hypoplastic and translucent irides, miosis and high myopia. The lenses may be dislocated as in familial Marfan syndrome but they are often in place and microspherophakic. The clinical history of a boy with CMC is presented. Pathological examination of the eyes showed megalophthalmos with thinned sclera, anomalies of the chamber angle and iris, ill-developed ciliary body and choroid and a small in situ lens.

Ophthalmologic and systemic features of the Alström syndrome: report of 9 cases.

The Alström syndrome is a rare autosomal recessive disorder characterized by pigmentary retinopathy, diabetes mellitus, sensorineural deafness and obesity. A normal intelligence is often present. We report 9 patients.

Autosomal dominant congenital miosis with megalocornea.

A family with AD congenital miosis is presented. The ocular symptoms were: megalocornea, iris translucency, microcoria with poor pupillary dilatation and goniodysgenesis with anterior insertion of the iris. This observation confirms that in congenital miosis abnormal development of the whole anterior eye segment may occur. The patients have an increased risk to develop glaucoma. If retinoscopy is impossible due to pin-point pupils, ultrasonic biometry to determine the axial length is recommended. An optical iridectomy could improve visual performance at low illumination; the complaints of photophobia, which are related to the iris translucency, persist.

Lens dislocation and optic nerve hypoplasia in ring chromosome 21 mosaicism.

Data on the physical and cognitive development of patients with chromosomal aberrations are scarce. In this report the authors present data on the longterm evolution in a boy with 45, XY,-21/46, XY, r(21) mosaicism, from birth up to the age of 14 years. Ophthalmological examination revealed lens dislocation and optic nerve hypoplasia.

Mental retardation in amaurosis congenita of Leber.

A group of 229 patients with Leber's congenital amaurosis (ACL) was investigated for associated defects. We especially looked for the occurrence of mental retardation because the literature gives varying frequencies for this association. A percentage of 19.8% was found. This finding has consequences for genetic counseling. Special attention was given to how frequently sibling pairs occurred in which one patient was mentally retarded whereas the other functioned normally. We found 11 sibling pairs that were discordant with regard to their mental state. This observation proves that mental retardation could be one variable expression of ACL.

Ocular manifestations of congenital Marfan syndrome with contractures (CMC syndrome).

The authors present the results of ocular examination of six children with congenital Marfan syndrome with contractures (CMC syndrome). The ocular and neuroradiological findings of the CMC syndrome are discussed with reference to the literature. The ocular findings are: blue sclerae, megalocorneas, hypoplastic irides with complete translucency, miosis, spherophakia with or without lens dislocation and severe myopia. This study demonstrates that ophthalmological examination of children with congenital contractures and arachnodactyly is very helpful for diagnosis of the CMC syndrome. The authors stressed that ophthalmologists should not only look for luxation of the lens in children who are suspected of having CMC syndrome. Spherophakia was common in the children and could easily be observed through the translucent irides. Biometric evaluation of the eyes is recommended. All of the cases in this paper and reported cases are sporadic. No conclusions have been reached in the literature on whether the CMC syndrome represents the severe expression of the classical Marfan syndrome or a distinct entity. Maybe the answer will remain difficult, until the specific molecular defects in the collagen diseases are discovered. This study demonstrates that ophthalmological examination of the children with congenital contractures and arachnodactyly is very helpful for the diagnosis of CMC syndrome.

X-linked megalocornea. Ocular findings and linkage analysis.

A family with X-linked megalocornea (XMC) is presented. The most typical ocular features of the disease (cornea globosa, arcus lipoides, mosaic dystrophy of the cornea, pigment dispersion, and cataract) are described and their diagnostic value is discussed by reviewing the literature. Linkage data suggest that the XMC locus maps in the region Xq13-q25, most probably in Xq21-q22.