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Biomedical subjects

C S Hoyt

Publications and source records attributed to C S Hoyt.

At least 19 recordsLinked to original sources
PubMed2000

Mutation analysis of 3 genes in patients with Leber congenital amaurosis.

OBJECTIVE: To assess the frequency of mutations in the CRX, GUCY2D, and RPE65 genes in patients with Leber congenital amaurosis (LCA). PATIENTS: One hundred seventy-six probands with a clinical diagnosis of LCA were from 9 countries, with the largest subgroup being 39 probands from India. METHODS: Samples were screened with single-strand conformation polymorphism analysis followed by DNA sequencing of 3 genes (CRX, GUCY2D, and RPE65) known to be associated with LCA. RESULTS: Of the 176 probands, 28 (15.9%) harbored possible disease-causing mutations. The relative contribution of each gene to the total number of mutations was as follows: CRX, 2.8%; GUCY2D, 6.3%; and RPE65, 6.8%. No patients who harbored mutations in these genes had associated systemic abnormalities. Molecular diagnosis allowed definitive genetic counseling in a family affected with Best disease and LCA. CONCLUSIONS: Molecular diagnosis may be of benefit to patients affected with LCA. The relative paucity of mutations found in this study suggests that more LCA-associated genes remain to be discovered. CLINICAL RELEVANCE: Molecular diagnosis can confirm and clarify the diagnosis of LCA. As genotype data accumulate, clinical phenotypes associated with specific mutations will be established. This will facilitate the counseling of patients on their visual prognosis and the likelihood of associated systemic anomalies.

Adolescent↗
PubMed1999

Chronic cortical visual impairment in children: aetiology, prognosis, and associated neurological deficits.

BACKGROUND/AIMS: To evaluate prevalence, aetiology, prognosis, and associated neurological and ophthalmological problems in children with cortical visual impairment (CVI). METHODS: The records of 7200 outpatients seen in the paediatric ophthalmology practice over the past 15 years were reviewed in order to compile data concerning CVI. In addition, the authors devised and applied a system for grading visual recovery in order to assess prognosis. RESULTS: CVI occurred in 2.4% of all patients examined. The four most common causes of CVI were perinatal hypoxia (22%), cerebral vascular accident (14%), meningitis (12%), and acquired hypoxia (10%). Most children with CVI had associated neurological abnormalities. The most common were seizures (53%), cerebral palsy (26%) hemiparesis (12%), and hypotonia (5%). Associated ophthalmological problems were esotropia (19%), exotropia (18%), optic nerve atrophy (16%), ocular motor apraxia (15%), nystagmus (11%), and retinal disease (3%). On average, CVI patients improved by two levels as measured by the authors' scale. CONCLUSION: The majority of children with CVI showed at least some recovery. In this group of children, CVI is often accompanied by additional ophthalmological problems and is nearly always associated with other, serious neurological abnormalities.

Blindness, Cortical↗
PubMed1998

Complex limbal choristomas in linear nevus sebaceous syndrome.

OBJECTIVE: This study aimed to describe the clinical and histopathologic findings in four patients with complex limbal choristomas associated with linear nevus sebaceous syndrome (LNSS), a rare disorder including nevus sebaceous, seizures, and mental retardation, and often accompanied by ocular anomalies. DESIGN: Small observational case series. METHODS: A retrospective review of the clinical and histopathologic records of four patients. RESULTS: Each of four patients had complex limbal choristomas in the setting of clinical and histopathologic LNSS. The limbal choristomas were multiple in three patients and bilateral in two patients. Most choristomas involved the superotemporal limbus (6 of 10), although nasal (3 of 10) and inferior (1 of 10) limbal tumors also were present. Three patients had significant corneal astigmatism or involvement of the central cornea requiring surgical removal of their choristomas, one accompanied by a lamellar keratoplasty and another accompanied by two consecutive penetrating keratoplasties. Each graft eventually vascularized, reducing vision. One patient's vision was limited by amblyopia and another by occipital cortical dysgenesis with visual impairment. Histopathologic examination of the excised choristomas showed foci of lacrimal gland (3 of 4 patients), adipose tissue (3 of 4), neural tissue (1 of 4), cartilage (1 of 4), lymphoid follicles (1 of 4), skin adnexal tissue (1 of 4), and smooth muscle (1 of 4). Other associated ocular findings included an eyelid mass (1 of 4), colobomas of the eyelid (3 of 4), colobomas of the choroid and retina (2 of 4), nonparalytic strabismus (2 of 4), scleral ectasia (1 of 4), partial oculomotor palsy with ptosis and anisocoria (1 of 4), microphthalmia (1 of 4), hypertelorism (1 of 4), and cortical visual impairment (1 of 4). CONCLUSIONS: Complex limbal choristomas, although rare, can occur in the setting of LNSS and can be associated with multiple ocular and systemic abnormalities. Visual prognosis appears poor in most cases despite aggressive management.

Child, Preschool↗
PubMed1998

Does Horner's syndrome in infancy require investigation?

AIMS: To evaluate whether isolated Horner's syndrome presenting in the first year of life warrants investigation. METHODS: Retrospective review of 23 children presenting with Horner's syndrome in the first year of life. RESULTS: In 16 patients (70%) no cause was identified. Birth trauma was the most common identifiable cause (four patients). Twenty one children (91%) had urinary vanillylmandelic acid (VMA) measured and 13 patients (57%) underwent either computed tomography or magnetic resonance imaging of the chest and neck. These investigations revealed previously undisclosed pathology in only two--one ganglioneuroma of the left pulmonary apex and one cervical neuroblastoma. A further patient was known to have abdominal neuroblastoma before presenting with Horner's syndrome. There were no cases of Horner's syndrome occurring after cardiothoracic surgery. Long term follow up of the patients (mean 9.3 years) has not revealed further pathology. CONCLUSIONS: Routine diagnostic imaging of isolated Horner's syndrome in infancy is unnecessary. Infants should be examined for cervical or abdominal masses and involvement of other cranial nerves. If the Horner's syndrome is truly isolated then urinary VMA levels and follow up in conjunction with a paediatrician should detect any cases associated with neuroblastoma. Further investigation is warranted if the Horner's syndrome is acquired or associated with other signs such as increasing heterochromia, a cervical mass, or cranial nerve palsies.

Abdominal Neoplasms↗
PubMed1997

Sudden death in septo-optic dysplasia. Report of 5 cases.

OBJECTIVES: To report our experience with sudden death in children with septo-optic dysplasia and to identify specific risk factors and suggest preventive measures to minimize mortality. METHODS: Clinical data from 5 children with septo-optic dysplasia who died suddenly and unexpectedly were evaluated retrospectively. RESULTS: All children had corticotropin deficiency, all had thermoregulatory disturbances, and 4 children had diabetes insipidus. In at least 4 children, clinical deterioration was caused by fever and dehydration from a presumed viral illness, which appeared to precipitate adrenal crisis. CONCLUSIONS: Children with septo-optic dysplasia and hypocortisolism are at risk for sudden death during febrile illness. Thermoregulatory disturbances and dehydration from diabetes insipidus may potentiate clinical deterioration. Prevention of sudden death in septo-optic dysplasia requires early recognition and treatment of these major risk factors.

Adrenocorticotropic Hormone↗
PubMed1997

Aqueous hyaluronic acid concentration: comparison in pediatric and adult patients.

PURPOSE: To determine if there is an age-related increase in human aqueous hyaluronic acid (HA) concentration. METHODS: HA concentrations were measured in 102 specimens of human aqueous humour obtained during intraocular surgery. Patient age ranged from one month to 93 years. Measurement of the HA concentration in the specimens was performed by a modified ELISA-like assay using a biotinylated HA-binding peptide. RESULTS: An approximate five-fold increase in the mean aqueous HA concentration was observed between the pediatric (0.33 microgram/ml, n = 5) and the adult patients (1.72 micrograms/ml, n = 97, p < 0.0002). Among the adult patients, however, there was a poor correlation between age and aqueous HA concentration. CONCLUSIONS: Adult aqueous humor has a significantly higher HA concentration than aqueous obtained from pediatric patients. The source of this increase is unclear, but may be from anterior segment production of HA, or alternatively, from anterior diffusion of vitreous HA.

Adult↗
PubMed1995

Atypical retinochoroidal coloboma in patients with dysplastic optic discs and transsphenoidal encephalocele.

OBJECTIVE: To evaluate the clinical significance of V- or tongue-shaped infrapapillary retinochoroidal depigmentation in association with dysplastic optic discs. METHODS: Clinical data from all patients with V- or tongue-shaped infrapapillary retinochoroidal depigmentation and dysplastic optic discs were evaluated retrospectively. RESULTS: Five patients with this atypical colobomatous anomaly had transsphenoidal encephalocele. A sixth patient had an ectopic midline pharyngeal mass with no skull-base defect. CONCLUSION: In patients with optic disc dysplasias, the finding of this V- or tongue-shaped retinochoroidal pigmentary anomaly should prompt neuroimaging to look for transsphenoidal encephalocele.

Adolescent↗
PubMed1993

Monocular visual outcome in untreated early onset esotropia.

The incidence of amblyopia was analysed in a group of 20 patients with early onset esotropia. These patients reached adulthood without any form of previous treatment. The incidence of amblyopia was compared in a group of 20 patients who received conventional treatment, including occlusion and early surgical alignment. Only three patients (15%) in the untreated group presented with amblyopia, compared with 16 (80%) in the treated group. After treatment 35% of the control group remained amblyopic. Spherical anisometropia of more than 2 dioptres was present in two of the patients with amblyopia in the untreated group, but was not associated with amblyopia in the control group. Early surgical alignment permits the development of peripheral fusion, allowing long term alignment stability, but amblyopia appears to be more common after surgical alignment.

Adolescent↗
PubMed1992

Surgical management of myokymia of the superior oblique muscle.

In the past 15 years, we have examined 20 patients in whom myokymia of the superior oblique muscle was diagnosed. Medical treatment (carbamazepine) failed in three patients, and one patient did not accept drug therapy. These four patients (20%) were operated on for persistent oscillopsia and diplopia. One patient underwent only a superior oblique muscle myotomy, but required an inferior oblique muscle myectomy six months later because of iatrogenic superior oblique muscle palsy. The other three patients underwent simultaneous superior oblique muscle myotomy and inferior oblique muscle myectomy. The symptoms resolved postoperatively in all four patients. Symptomatic patients with superior oblique muscle myokymia in whom medical treatment fails or is intolerable can benefit from surgical treatment consisting of combined superior oblique muscle/inferior oblique muscle myectomy.

Adult↗