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At least 19 recordsLinked to original sources
PubMed1978

Differential diagnosis of typical and atypical congenital achromatopsia. Analysis of a progressive foveal dystrophy and a nonprogressive oligo-cone trichromasy (general cone dysfunction without achromatopsia), both of which at first had been diagnosed as achromatopsia.

Report on two patients whose symptoms suggested the presence of congenital achromatopsia. In one case there was indeed total colour blindness, but a normal photopic ERG. Here, achromatopsia is the present stage in a process of slow functional decay of the central retina. Most probably the underlying disorder is progressive foveal dystrophy, a central form of cone dystrophy. In the other case there was a nonrecordable photopic ERG, but trichromatic colour vision. This appears to be another patient with oligo-cone trichromasy (general cone dysfunction without achromatopsia), as described by Van Lith.

Adult↗
PubMed2024

Clinical characterizations and molecular genetic study of two co-segregating variants in PDZD7 and PDE6C genes leading simultaneously to non-syndromic hearing loss and achromatopsia.

BACKGROUND: Autosomal recessive non-syndromic hearing loss (NSHL) and cone dystrophies (CODs) are highly genetically and phenotypically heterogeneous disorders. In this study, we applied the whole exome sequencing (WES) to find the cause of HL and COD in an Iranian consanguineous family with three affected individuals. METHODS: Three members from an Iranian consanguineous family who were suffering from NSHL and visual impairment were ascertained in this study. Comprehensive clinical evaluations and genetic analysis followed by bioinformatic and co-segregation studies were performed to diagnose the cause of these phenotypes. Data were collected from 2020 to 2022. RESULTS: All cases showed congenital bilateral NSHL, decreased visual acuity, poor color discrimination, photophobia and macular atrophy. Moreover, cornea, iris and anterior vitreous were within normal limit in both eyes, decreased foveal sensitivity, central scotoma and generalized depression of visual field were seen in three cases. WES results showed two variants, a novel null variant (p.Trp548Ter) in the PDE6C gene causing COD type 4 (Achromatopsia) and a previously reported variant (p.Ile84Thr) in the PDZD7 gene causing NSHL. Both variants were found in the cis configuration on chromosome 10 with a genetic distance of about 8.3 cM, leading to their co-inheritance. However, two diseases could appear independently in subsequent generations due to crossover during meiosis. CONCLUSIONS: Here, we could successfully determine the etiology of a seemingly complex phenotype in two adjacent genes. We identified a novel variant in the PDE6C gene, related to achromatopsia. Interestingly, this variant could cooperatively cause visual disorders: cone dystrophy and cone-rod dystrophy.

Adult↗
PubMed1978

Congenital achromatopsia in a Finnish family.

A family with two achromatic members, a sister and brother, is described. Their parents were first cousins. Eye examination of the 34 relatives examined revealed no abnormalities in 32. The son of their youngest brother was deuteranomalous. However, since this recessive trait is X chromosome linked, this failure was not related to the achromatopsia gene. The granddaughter of their eldest brother had difficulties in colour vision tests and was interpreted as an anomalous trichromat of unclassified nature. This might be a slight intermediate heterozygotic manifestation of the gene. The information of those relatives not examined revealed only a deceased paternal aunt who had had poor vision of an unknown cause. Congenital achromatopsia is rare but nevertheless should be kept in mind in cases of unexplained amblyopia. The nature of this disorder justifies the opthalamologist to inform these patients of the hereditary character of this disease and to give advice on educational guidance to them.

Adult↗
PubMed1979

Eight cases of congenital achromatopsia with amblyopia in two pedigrees from Northern Sweden.

Two families from northern Sweden with a total of 8 patients with typical symptoms of congenital achromatopsia with amblyopia were studied. In one of the families 4 affected children (3 brothers and 1 sister) also showed pallor of the optic discs and marked astigmatism. The transmission of the disease was consistent with an autosomal recessive inheritance in both families. The study confirmed that complete and incomplete achromatopsia might be different expressions of the same gene. Six out or 13 near relatives of the achromatic patients showed minor colour vision defects, suggesting a tendency towards heterozygotic manifestation of the gene.

Adolescent↗
PubMed1978

Autosomal recessive incomplete achromatopsia with protan luminosity function.

A unique form of dichromatic color vision is described in a family with incomplete achromatopsia. In 1966, incomplete achromatopsia was diagnosed in 4 of 14 children of a consanguineous marriage. The 4 affected had best visual acuities of 6/60 or 6/180, pendular nystagmus, and aversion to bright lights. The ERG showed minimal photopic responses. No abnormality of rod function was present. There was a severe color vision defect. In 1976, one of the patients returned for further color testing. Color tests included measurement of the luminous efficiency function using heterochromatic flicker photometry and colorimetric evaluation. The luminous efficiency function resembled that of the protanope. From the colorimetric measurements, we conclude that the patient has a unique form of dichromatic color vision mediated by two visual photopigments: the normal MWS cone photopigment and a photopigment with the spectral characteristics of rhodopsin.

Adolescent↗
PubMed1978

[Field of vision established by perimetry in achromatopsia (author's transl)].

The results of perimetry especially of profile perimetry is in cases of achromatopsia so typical and unmistakable that it can be referred to for the differentia. l diagnosis of this disease. This follows from an examination of 33 cases with congenital achromatopsia. In all cases profile perimetry was flattened in the fixation area but not nearly as strong as it is usually the case if visual acuity is decreased to 0,1. 7 times there was found a small central scotoma at the margin of which it is fixated. The reason for the diverging of light difference sensitivity and visual acuity is discussed.

Color Vision Defects↗
PubMed1979

Autosomal recessive incomplete achromatopsia with deutan luminosity.

Four patients in three different families had a form of autosomal recessive incomplete achromatopsia not previously described. The visual acuity was 6/18 to 6/60 (20/60 to 20/200) with minimal ophthalmoscopic abnormality and normal fluorescein angiogram. The photopic electroretinographic responses were present in all four patients; the fusion rate of 60 Hz was only slightly subnormal. The high-intensity scotopic response was subnormal. The patients failed color screening plates and accumulated over 400 errors with scotopic axis on the Farnsworth-Munsell 100-hue test. The Rayleigh match was abnormal, displaced toward the red primary, but with normal luminance. The photopic luminous efficiency function was similar to that of the deuteranope. Color matching revealed a trichromatic form of color vision mediated by long wavelength and short wavelength cones, and a rhodopsin receptor.

Adolescent↗
PubMed1978

Incomplete achromatopsia in Bishnupur.

Nine males and 2 females from the Shankhabanik Community in Bishnupur, provisionally diagnosed as incomplete rod achromats by Bose, Joardar and Sukul in 1968, with 2 new similar males, were tested more fully with six colour vision tests. All had photophobia, nystagmus of fixation, extremely low visual acuity and extreme loss of colour sense with shortened red spectrum. 40 other males and 24 females, relatives of the defectives, were also tested for comparison. The provisional diagnosis was confirmed, and the hypothesis of autosomal inheritance seemed most probably true. Various details about the relatives emerged.

Color Vision Defects↗
PubMed1977

Inbreeding in recessive diseases.

The consanguinity of parents (born in France) of individuals who have a recessive disease has been studied. The frequency of first cousin marriages is less than 0.2% in the general French population. Among the parents of affected individuals the following frequencies of first cousin matings were observed: cystic fibrosis: 1.4% cystinosis: 7.1% nephronophtisis: 5.6% spinal muscular atrophy: 4.5% albinism: 5.0% achromatopsia: 12.5% (Albinism and spinal muscular atrophy are heterogeneous conditions). The increase in the frequency of first cousin marriage relative to that of the general population is much greater, as expected, in cystinosis, which is a rare disease, than in cystic fibrosis, which is the most frequent recessive disorder in France. Inbreeding in cystinosis and cystic fibrosis was also studied by computing the distance between parental birth places. This distance is smaller in cystinosis than in cystic fibrosis.

Albinism↗
PubMed1992

Berson test for blue cone monochromatism.

The Berson test for blue cone monochromatism discriminates X-linked blue cone monochromatism from achromatopsia but not from X-linked progressive c dystrophy.

Color Perception Tests↗
PubMed1975

[Acquired and congenital monocular pendular nystagmus. A comparative electronystagmographic study of two cases (author's transl)].

Comparative analysis of two cases of monocular pendular nystagmus (MPN). The nystagmus was acquired in one case of multiple sclerosis, and congenital in the other patient who had achromatopsia. A postsaccadic inhibition of 0.6-1 sec duration was seen only in the case of acquired MPN. All the other characteristics of the acquired and congenital monocular nystagmus were identical. The waveform of the nystagmus was sinusoidal, triangular or mixed. There was no modification of the MPN by eye position or by smooth pursuit. The nustagmus was inhibited by lid closure. Oscillopsia was reported by both patients. A peculiar disturbance of the sensorimotor feedback loop of the visual system is discussed as the possible common pathogenesis of acquired and congenital pendular nystagmus.

Cerebral Cortex↗
PubMed1992

Maternal uniparental isodisomy of chromosome 14: association with autosomal recessive rod monochromacy.

Rod monochromacy (complete congenital achromatopsia) is inherited as an autosomal recessive trait of unknown genetic location. The disorder is characterized by total absence of color discrimination because retinal cone photoreceptors do not develop; systemic features do not occur. A 20-year-old white female with rod monochromacy presented with short stature (less than 5th percentile), mild developmental delay, premature puberty, small hands and feet (length less than 5th percentile), minimal dysmorphism, and a reproductive history of three consecutive first-trimester miscarriages. Cytogenetic analysis showed 45,XX,rob(14;14) in all 30 cells examined. Southern analysis of DNA from the patient and her phenotypically normal mother and two brothers (her father is deceased) ascertained the parental origin of the 14;14 Robertsonian translocation. Analysis of RFLPs associated with nine VNTR probes and two dinucleotide repeat polymorphisms from chromosome 14 demonstrated that the patient had inherited two copies of a single allele, each of which was maternally derived. A fully informative RFLP analysis of three probes from chromosome 14 enabled reconstruction of the paternal haplotype and showed the lack of any paternal contribution to the subject. These data are consistent with maternal isodisomy for all portions of chromosome 14 tested by these markers. This finding suggests that rod monochromacy maps to chromosome 14, and it emphasizes the importance of uniparental isodisomy to provide a putative chromosomal assignment of a gene for a rare autosomal recessive disorder.

Chromosome Mapping↗
PubMed1992

Cortical area V4 and its role in the perception of color.

The color and lightness vision of three monkeys with bilateral removal of cortical area V4 and three unoperated controls were tested by measuring their ability to discriminate between two rows of colored or gray stimuli. In one row, the stimuli were ordered in terms of either chromaticity or luminance, whereas in the other row they were disordered. Their ability to select the odd-one-out in an array of colors or grays and to select the colored patch from an array of achromatic grays was also assessed. Unlike an achromatopsic patient tested previously in an identical fashion, monkeys with V4 lesions performed indistinguishably from controls in the oddity test. The animals lacking V4 were slightly impaired at discriminating between ordered and disordered arrays of colors or grays, but the color impairment was no more severe than the impairment with grays. These deficits were readily accounted for in terms of the conspicuous deficits in pattern discrimination apparent in a nine-choice pattern oddity task. The results do not support the view that cortical area V4 in the monkey is the homolog of the cortical "color center" in humans, located in the lingual and fusiform gyri and damage to which leads to the clinical syndrome of cerebral achromatopsia, unless it is the additional damage to underlying white matter that leads to the severe color disorder in patients.

Animals↗
PubMed1978

Congenital nystagmus--genetic and environmental causes.

A survey of 40 individuals registered with the Canadian National Institute for the Blind (CNIB) as blind from congenital nystagmus revealed that an abnormal single gene was responsible for the disorder in 33 patients. Fifteen of these were due to autosomal recessive conditions while X-linked disorders accounted for another 15 patients. In 3 cases the pedigrees were consistent with both autosomal recessive or X-linked inheritance. A clearly defined environmental origin was present in 1 case while specific genetic or environmental factors were not detected in the remaining six patients. The albinism, achromatopsia and Leber's congenital amaurosis groups of disorders were those most frequently detected.

Adolescent↗