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Biomedical subjects

H M Hittner

Publications and source records attributed to H M Hittner.

At least 37 records · Page 2Linked to original sources
PubMed1982

Oculocutaneous albinoidism as a manifestation of reduced neural crest derivatives in the Prader-Willi syndrome.

Nine patients with Prader-Willi syndrome (five female and four male; one Oriental and eight white), all of whom had interstitial deletions of the proximal long arm of one chromosome 15 (q11-q13) were found to have decreased tyrosinase activity in isolated hair bulbs. As infants, all patients had light hair and skin coloring, both of which darkened with age. Light and electron microscopic analysis of skin and hair bulbs disclosed a reduced number of melanocytes in the basal epidermis and hair bulbs. Each patient demonstrated decreased pigmentation of the iris stroma, which was accentuated peripherally and manifested clinically as iris translucency. There was no foveal hypoplasia, nystagmus, or photophobia, and ocular function was normal. Oculocutaneous albinoidism is thus a component of del(15q) Prader-Willi syndrome with reduction of melanocytes of neural crest origin (skin, hair, and iris stroma) and retention of normal retinal and iris pigment epithelia of neuroectodermal origin.

Adolescent↗
PubMed1982

Variable expressivity of autosomal dominant anterior segment mesenchymal dysgenesis in six generations.

Of 58 members in a six-generation family with anterior segment mesenchymal dysgenesis with variable expressivity, 21 of 35 members (60%) at risk were affected. Of the 15 living affected family members, nine (60%) had visual acuities of 6/12 (20/40) or better in at least one eye, five (33%) had visual acuities between 6/15 and 6/60 (20/50 and 20/200) in at least one eye, and one (7%) had a visual acuity of less than counting fingers at one foot in both eyes. All nine affected patients who underwent slit-lamp examinations had corneal abnormalities with and without synechiae. All 15 affected patients also had cataracts, and three of the 15 (20%) had optic nerve abnormalities. In a corneal button from the severely affected proband, Descemet's layer and endothelial cells were absent even in the periphery. Other corneal and lenticular changes were secondary to the primary endothelial defect. Anterior segment mesenchymal dysgenesis in this family appeared to be caused by an aberration of the first wave of mesenchyme from the rim of the optic cup.

Adolescent↗
PubMed1982

Wilms tumor with aniridia/iris dysplasia and apparently normal chromosomes.

Two patients with Wilms tumor, iris dysplasia (complete aniridia in one and subtle iris defects in the other), normal karyotypes, and no gene loss demonstrable by enzyme marker and direct DNA analyses are presented. The findings indicate that aniridia and less severe iris defects define a risk for Wilms tumor even in the absence of del (11p13), and that there is as yet no consistent biochemical genetic marker for the aniridia-Wilms tumor association.

Adolescent↗
PubMed1982

Retinal detachment in young premature infants with acute retrolental fibroplasia. Thirty-two new cases.

Experience with scleral buckling for exudative and tractional retinal detachments in very young premature infants who have acute retrolental fibroplasia (RLF) is reported. In this series, surgery was successful in 24 of 32 eyes (75%) of 23 infants, (age at surgery ranged from 1.75 months to 6 months, average age of 3 months). We attribute the 15% improvement in the success rate over our 1979 series in part to closer screening with emphasis on the examination at age 8 weeks, to earlier referral for treatment, and to our observation that these fragile eyes can withstand reoperation if buckle revision is necessary to combat persistent retinal traction. We encountered no serious complications either at surgery or immediately after surgery. We stress that (1) because of the high incidence of spontaneous remission, buckling surgery should not be performed until the detachment has progressed well posterior to the equator and remission is obviously unlikely (Grade IV or V); (2) excessive cryotherapy and undue surgical trauma should be avoided; and (3) because scleral erosion is certain as the eyes grow, the encircling band should be transected six months to one year after surgery.

Female↗
PubMed1982

Anterior segment mesenchymal dysgenesis: probable linkage to the MNS blood group on chromosome 4.

Thirty-seven blood samples were analyzed for linkage from members of a single family with an anterior segment mesenchymal dysgenesis (ASMD1) with variable expressivity affecting members of at least six generations. Maximum-likelihood analysis for linkage between ASMD1 and 14 biochemical and serological markers in the family showed a probable linkage between ASMD1 and the MNS blood group on the long arm of chromosome 4 (Z = 2.36 at a recombination fraction of .09).

Chromosome Mapping↗
PubMed1982

Linkage studies in carriers of Lowe oculo-cerebro-renal syndrome.

A black family with two male infants affected with the X-linked Lowe syndrome was studied. All three females in the pedigree were found to be carriers on the basis of lenticular opacities. Each female had one son. Of these, two were affected and one was unaffected. The Xg blood-group locus and the G6PD locus were determined in these six individuals. Two of the carrier females were heterozygous for G6PD isoenzymes A- and B. Skewing of the A-:B ratio in isolated erythrocytes, lymphocytes, granulocytes, platelets, and cultured skin fibroblasts from these females may be the result of either selection against cells expressing the Lowe gene product or random X-chromosome inactivation. At least one instance of recombination was found between the G6PD and the Lowe syndrome loci. At least two instances of recombination between Xg blood-group and Lowe syndrome loci.

Adolescent↗
PubMed1981

Retrolental fibroplasia: efficacy of vitamin E in a double-blind clinical study of preterm infants.

We performed a double-blind study in 101 preterm infants who weighed less than or equal to 1500 g at birth, who had respiratory distress, and who survived for at least four weeks, to evaluate the efficacy of oral vitamin E in preventing the development of retrolental fibroplasia. Weekly indirect ophthalmologic examinations begun when the infants were three weeks old revealed a significant decrease in the incidence of retrolental fibroplasia greater than or equal to Grade III (P less than 0.03) and greater than or equal to Grade II (P less than 0.05) (McCormick classification) in the 50 infants given 100 mg of vitamin E per kilogram of body weight per day as compared with 51 given 5 mg per kilogram per day (controls). When multivariate analysis was applied to the controls, five risk factors were identified: gestational age, level and duration of administration oxygen, intraventricular hemorrhage, sepsis, and birth weight. When multivariate analysis was applied to both control and treatment groups, the severity of retrolental fibroplasia was found to be significantly reduced in infants given 100 mg of vitamin E (P = 0.012).

Administration, Oral↗
PubMed1981

Zellweger syndrome. Lenticular opacities indicating carrier status and lens abnormalities characteristic of homozygotes.

Cataracts were found in four patients with pathologically confirmed Zellweger syndrome. By careful slitlamp examination with the pupil completely dilated, there is a denser cortex that produces a cortical-nuclear interface. These opacities have ultrastructural analogues, which are inclusion bodies restricted to the cortical lens fibers. The lens epithelium shows abnormal mitochondrial proliferation that is age dependent. The parents of these four infants with Zellweger syndrome have lenticular opacities that are seen only biomicroscopically after maximal pupillary dilation. These changes consist of curvilinear condensations in the cortical region corresponding to the locus of the cataractous changes in the homozygous state. In the clinical setting of an infant who is failing to thrive, has the Zellweger facies, and demonstrates an absent electroretinogram, these heterozygote lens opacities are useful in making the diagnosis of Zellweger syndrome before pathologic substantiation.

Cataract↗
PubMed1981

Ocular manifestations of the Smith-Lemli-Opitz syndrome.

To our knowledge, this article describes the first ocular histopathologic condition of a Smith-Lemli-Opitz proband, despite almost 60 clinical histories that exist in the literature. The sole retinal abnormality in this 1-month-old infant with congenital bilateral cataracts is the extensive dropout of peripheral ganglion axons with incipient optic nerve demyelination. Unusual amorphous cytoplasmic masses that are continuous with photoreceptor discs are prominent aspects of the peripheral subretinal space. The morphological data imply that the localized mitochondrial disintegration is restricted to the corneal endothelium and retinal pigment epithelium and is an important element in the etiology. All children who fail to thrive with vomiting, are mentally deficient, have anteverted nostrils, broad maxillary alveolar ridges, syndactyly of the second and third toes, and ambiguous genitalia should be carefully screened for incipient corneal endothelial changes, mild cataracts, and peripheral retinal changes.

Abnormalities, Multiple↗
PubMed1981

Autosomal dominant cone-rod dystrophy: a linkage study with 17 biochemical and serological markers.

Five generations of a family with autosomal-dominant cone-rod dystrophy (CRD) with complete penetrance have been previously studied extensively clinically. The young members of this family were reevaluated, and blood from 73 available family members was studied with 17 biochemical and serological markers. A total of 25 relatives was found to be affected. Linkage between the gene for CRD in this family and the markers studied could not be established by maximum likelihood analysis.

Adolescent↗
PubMed1981

An association between retinopathy of prematurity and intraventricular hemorrhage in very low birth weight infants.

An association between cicatricial retinopathy of prematurity and intraventricular hemorrhage in very low birth weight infants was investigated retrospectively. Newborns were studied who weighed less than or equal to 1500 g at birth, who were less than or equal to 32 weeks gestational age and appropriate by weight, and admitted in the first 24 hours of life to our Neonatal Intensive Care Unit. Diagnosis of retinopathy of prematurity was made by retinal examination at approximately 4 weeks of age. Diagnosis of intraventricular hemorrhage was made by computerized tomography and clinical findings. A total of 138 infants were studied and divided into two groups: (A) birth weight less than or equal to 1000 g (31); (B) birth weight 1001--1500 g (107). There was a statistically significant association between cicatricial retinopathy of prematurity and intraventricular hemorrhage in both groups. There were no statistical differences between birth weight, gestational age, duration of oxygen therapy, highest oxygen concentration received, Apgar scores, incidence of hyaline membrane disease and patent ductus arteriosus between cicatricial retinopathy of prematurity and no retinopathy of prematurity patients in either group. This association may be an important consideration in the pathogenesis of both vascular diseases.

Cerebral Hemorrhage↗
PubMed1980

Two-step mutation theory for retinoblastoma: ultrastructural support.

This study presents previously unreported ultrastructural support for a model for the incidence of retinoblastoma based upon a two-step mutation theory. Ostensibly uninvolved retina showed rod outer segment atrophy and cone outer segment retention correlating with electroretinography, and obliteration of synaptic development within the outer plexiform layer of the retina. The retinoblastoma obtained at age 9 days demonstrated incipient photoreceptor differentiation within the rosette components and minimal calcification of necrotic regions. A heritable interstitial deletion of the long arm of chromosome 13 is shown to be the basis for this child's congenital retinoblastoma.

Atrophy↗
PubMed1980

Duplication 11p11.3 leads to 14.1 to meiotic crossing--over.

An infant with macular dysfunction, cleft lip and palate, and developmental delay was shown to have an inverted duplication of 11p11.3 leads to p14.1 on the basis of meiotic recombination subsequent to an intrachromosomal "shift" in his mother. A half-sister had previously been shown [3] to have the reciprocal recombinant with resultant deletion of 11p11.3 leads to 11p14.1.

Abnormalities, Multiple↗
PubMed1980

Variable expressivity in autosomal dominant aniridia by clinical, electrophysiologic, and angiographic criteria.

Of 39 members in a family with autosomal dominant aniridia with variable expressivity, 16 members, representing 50% (15 out of 30) of those at risk, were affected. Of these, ten of 16 (63%) had visual acuity of 6/12 (20/40) or better in at least one eye, and six of 16 (37%) had visual acuity between 6/15 (20/50) and 6/60 (20/200) in at least one eye. Affected patients had nystagmus (12, 75%), cataracts (nine, 56%), strabismus (15, 94%), amblyopia (six, 37%), corneal pannus (one, 6%) glaucoma (one, 6%), macular hypoplasia (five, 31%), and optic nerve hypoplasia (one, 6%). The good visual acuity in this family indicates that absence of iris tissue is not responsible for the decreased visual acuity usually associated with aniridia. The decreased visual acuity correlates instead with a decreased macular reflex and with a decreased electroretinogram amplitude. Affected family members have abnormal persistence of vessels in the macular region angiographically, and when sufficient iris tissue is present to be studied angiographically, there are abnormal vascular loops and leakage of dye at the pupillary border.

Adolescent↗
PubMed1980

Autosomal dominant aniridia: probable linkage to acid phosphatase-1 locus on chromosome 2.

Maximum likelihood analysis for linkage between autosomal dominant aniridia and 12 biochemical and serological markers in a single large family showed a probable linkage between autosomal dominant aniridia and the enzyme acid phosphatase-1. The presence of an autosomal dominant aniridia gene linked to acid phosphatase-1 on chromosome arm 2p and the existence of an aniridia syndrome resulting from deletion of band 13 of the short arm of chromosome 11 establishes a chromosome basis for genetic heterogeneity of aniridia phenotypes.

Acid Phosphatase↗