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A rare form of Leber hereditary optic neuropathy (LHON) that is associated with hereditary spastic dystonia has been studied in a large Dutch family. Neuropathy and ophthalmological lesions were present together in some family members, whereas only one type of abnormality was found in others. mtDNA mutations previously reported in LHON were not present. Sequence analysis of the protein-coding mitochondrial genes revealed two previously unreported mtDNA mutations. A heteroplasmic A-->G transition at nucleotide position 11696 in the ND4 gene resulted in the substitution of an isoleucine for valine at amino acid position 312. A second mutation, a homoplasmic T-->A transition at nucleotide position 14596 in the ND6 gene, resulted in the substitution of a methionine for the isoleucine at amino acid residue 26. Biochemical analysis of a muscle biopsy revealed a severe complex I deficiency, providing a link between these unique mtDNA mutations and this rare, complex phenotype including Leber optic neuropathy.

Neuropathological findings in a 59-year-old male case of hereditary spastic dystonia with Leber's hereditary optic atrophy included: marked depletion of myelinated nerve fibres in the posterior funiculi, corticopontine tracts and striatum; practically complete neuronal depletion in the putamen and lateral part of the caudate, and mild cell loss in the substantia nigra. The putamina had changed into a spongy fibrillary scar, the pallidal fibres and laminae were practically all degenerated. Moreover, there was generalised mild fibre degeneration of the white matter. The optic nerve showed marked, predominantly central, loss of nerve fibres with demyelination.

We investigated 111 members of a five generation family with X linked cone dystrophy. The patients showed the characteristic picture of cone dystrophy. Routine ophthalmological examination of the carrier women showed no abnormalities. However, with detailed colour vision testing we were able to detect 87% of all obligate carriers.

A dominant cone dystrophy spanning seven generations was found in a pedigree from the Netherlands. The onset of the decline of visual acuity started after the age of 20, while a near complete absence of blue cone function (a so-called tritan defect) already existed before the presence of any ophthalmological abnormalities.

Tritanopia is an autosomal dominant genetic disorder of human vision characterize by a selective deficiency of blue spectral sensitivity. The defect is manifested within the retina and could be caused by a deficiency in function or numbers (or both) of blue-sensitive cone photoreceptors. We have used PCR, denaturing gradient gel electrophoresis, and DNA sequencing of amplified exons to detect in four of nine unrelated tritanopic subjects two different point mutations in the gene encoding the blue-sensitive opsin, each leading to an amino acid substitution. Segregation analysis within pedigrees and hybridization of oligonucleotides specific for each allele to DNA samples from control subjects support the hypothesis that these mutations cause tritanopia. These results complete the genetic evidence for the trichromatic theory of human color vision.

A large kindred, in which either Leber's hereditary optic atrophy, or a hereditary spastic dystonia, or a combination of both manifested over many generations was restudied after the first report on it in 1964. NMR scans revealed bilateral, and, in two patients with hemidystonia, unilateral necrosis with shrinkage of the putamen, in one case associated with total disappearance of the head of the caudate nucleus. Except for age-appropriate cortical atrophy in one instance, no other changes were observed in the brain, brainstem, and cerebellum. The putaminal necrosis appears as typical "striatal slits" on the NMR scans. It is argued that this rare disease, since the princeps description in 1964 only reported in England (1986) and the U.S.A (1986), is most likely a singular type of mitochondrial encephalopathy: it is associated with Leber's optic atrophy, and the NMR changes observed have been signalled in other mitochondrial encephalomyelopathies, such as Leigh's disease and MELAS.

The results of ophthalmological and colour vision studies are reported on 13 patients from a family with a dominant cone dystrophy spanning seven generations. The onset of visual deterioration occurred in the third or fourth decade. In the early stages of the disease, when visual acuity is still close to normal, a severe defect in the blue sensitivity is already present, as measured by spectral sensitivity curves and other tests suitable for the detection of tritan defects. In our opinion this condition represents a distinct entity with autosomal dominant inheritance.

A mild, non-transfusion dependent, beta thalassaemia phenotype is described in a Dutch patient homozygous for a mutation in the cleavage-polyadenylation sequence of the beta globin gene. The molecular basis of the mutation, AATAAA greater than AATGAA, was determined using denaturing gradient gel electrophoresis (DGGE) and direct sequencing of genomic DNA amplified by the polymerase chain reaction (PCR). Different fragments of the beta globin gene were amplified and analysed on DGGE for the presence of mutations. The fragment with an abnormal melting behaviour was reamplified and the base substitution in the polyadenylation sequence was identified by direct sequencing.

We describe a family with an as yet undescribed form of X-linked progressive cone dystrophy in a five-generation pedigree, from which we report here the results of 17 male patients and 31 obligate and 13 possible female carriers. The affected males showed the characteristic picture of cone dystrophy. Foveal cone photopigment density was impaired (judged from anomaloscope settings and foveal densitometry), even at an early stage of the disease. The carriers showed no fundus abnormalities, except occasional changes due to myopia. The anomaloscope demonstrated mild pseudoprotanomaly in 27 of 31 obligate carriers and in six of 13 possible carriers. Foveal densitometry findings performed in 11 carriers always agreed with the anomaloscope findings. We conclude that the findings of pseudoprotanomaly and abnormal density differences in females of this family were the only ocular abnormalities and thus are indicative of the carrier state.

Five families with the dysplastic nevus syndrome, in each of which one member had ocular melanoma, are reported. These five families were examined within a 3-year period in one medical center. To date only five other families with such a combination have been reported. We suggest a causal relation between ocular melanoma and the familial dysplastic nevus syndrome.

The Familial Atypical Multiple Mole-Melanoma Syndrome (FAMMM) is characterized by an autosomal dominantly inherited susceptibility to multiple atypical naevi. Patients with this hereditary phenotype show a strong susceptibility to cutaneous malignant melanoma (CMM). Our investigation of an extended Dutch kindred showing the FAMMM phenotype revealed a proband with bilateral intraocular malignant melanoma (IOM) and multiple CMM. The family revealed an array of tumours which included carcinoma of the lung, skin, larynx, and breast in addition to CMM and IOM, which were transmitted vertically through 3 generations. There was male-to-male transmission, and the number of affected males and females was about the same, which was consistent with an autosomal dominant inheritance. Thus the FAMMM syndrome not only indicates a potential for CMM, but a susceptibility to other systemic cancers as well. These observations, though limited to a single kindred, merit a painstaking evaluation of cancer of all anatomical sites in other kindreds showing the FAMMM syndrome. Such studies could yield clues to cancer aetiology, pathogenesis, and control.

Bird et al. (1974) noted an interesting 'anticipation' phenomenon in Huntington's Chorea occurring in patients who inherited the gene from their father. More extensive samples from 165 pedigrees in the Low Countries permitted us to show that most of this apparent 'anticipation' is an artifact due to sampling biases related to the year of birth categories of the affected parents. When these biases were excluded no differences exist between the ages of death of affected mothers and their affected children, but a small difference of approximately two years remains between affected fathers and their affected children. This is explainable by the observation that juvenile cases of Huntington's Chorea usually have inherited the abnormality from their father.

For 1100 patients with Huntington's Chorea in 102 families from The Netherlands the average age at death per family is presented. This average ranges from 72 to 38 years. An analysis of variance of the data is strongly indicative of genetic heterogeneity. For the patients with the relatively high age at death little or no difference is observed from the age at death of their non-affected parents and non-affected sibs. Eleven children who presented with the juvenile form of the disease had all inherited the abnormal gene from their father. These 11 children were found only in families with an average age at death below 57 years. Other factors that might possibly influence the variation of average age at death between families are discussed, but cannot explain the observed differences.

An exhaustive study of erythropoietic protoporphyria in the Netherlands led to the discovery of 200 patients with this disorder in 91 families. In 46 of these families a single patient occurred. A study of parents, sibs and children led to the conclusion that the disease of erythropoietic protoporphyria is inherited as an autosomal recessive disorder. The presence of an occasional fluorescent red blood cell combined with normal protoporphyrin levels was observed in half of the children and sibs of patients and one of their parents; this phenomenon is therefore inherited as an autosomal dominant character. From an analysis of the findings in the 91 families we put forward the hypothesis of a 3-allele system.

A family is presented in which Hb Lepore Boston was found in six individuals over three generations. The gene must have had its origin either in Java (Indonesia) or in what is now the Federal Republic of Germany. The haemoglobin was characterized by amino-acid analysis of the six tryptic peptides that have a different composition in the beta- and the delta-chain. The ratio of glycine to alanine in position 136 of the fetal haemoglobin, which was somewhat raised in the Hb Lepore carriers, averaged 31:39. In addition an elliptocytosis gene was found, which was inherited independently from Hb Lepore; the simultaneous presence of elliptocytosis in three family members did not seem to aggravate the mild anaemia caused by Hb Lepore.

Three sibs are described suffering from hereditary non-progressive spinal muscular atrophy with non-progressive mental retardation. One of them had in addition signs of pyramidal tract involvement. Muscular weakness was more pronounced proximally than distally and the neck muscles were severely involved. Th.ey all had small skulls and several associated congenital malformations were observed including syndactyly of the left hand in 1 patient. The patients belong to a small inbred community in the Netherlands. Erythropoietic protoporphyria was also present in the family but segregated independently. This combination of "congenital" mental retardation with "congenital" non-progressive spinal muscular atrophy is believed to represent a new syndrome, caused by a rare recessive gene.

Two different population samples in Holland--one consisting of 1,093 boys from a technical school and the other of 493 male and 416 female students--were analysed for the presence of red-green colour vision defects. A total percentage of 7.3 for the male population was found. Based on the combined results of the Ishihara and HRR pseudoisochromatic plates, the Farnsworth 15-hue test and the anomaloscope, a subdivision of the deuteranomalous individuals into 3 subgroups is made. It is suggested that the differences between these groups may be genetic in nature and that the actual number of different genetic entities may still be greater.

In two families with autosomal dominant olivopontocerebellar atrophy (type IV), 15 affected and 44 unaffected members were typed for 28 genetic markers, including HLA. The lod scores for a possible HLA linkage, plotted against recombination fractions from 0.01 to 0.4, were negative. No evidence emerged for the presence of the ataxia-locus within measurable distance of the HLA-loci on chromosome 6. No indications were obtained that the ataxia-gene is linked with one of the other marker-genes.

Tritan (blue-green) colour vision disturbances have been found in 79 individuals in six families, revealing an autosomal dominant mode of inheritance with a wide variability of test results within families. Evidence is presented that it is--in contradistinction to the X-chromosomally inherited red-green defects--incorrect to make a subdivision between dichromasia (tritanopia) and anomalous trichromasia (tritanomaly). On the basis of three small screening series, totalling 1900 individuals, the frequency of tritan disturbances is estimated to be around 2 per 1000. Seven males have been observed carrying both inherited tritan and red-green defects.

The medical history of a patient with a familial atypical multiple more melanoma syndrome revealed a combination of rare findings: occurrence of a melanoma in both eyes, development of 3 separate skin melanomas, and occurrence of other malignancies in the family. Another patient developed a choroidal and a skin melanoma, but there were no known malignancies in the family. A third patient with a choroidal melanoma had a mother with an ethmoidal melanoma.

A detailed ophthalmological study on 72 individuals at risk to develop Leber's Optic Neuropathy (L.O.N) has revealed that early signs may be present. These included usually non-specific signs such as tortuosity of the peripapillary capillaries as best seen on fluorescein angiography; hyperaemia and a hazy boundary of the disc; relative paracentral and central scotomata; abnormal VERs; and increases in the error score with the Farnsworth 100-Hue test. The only possibly specific sign may be tortuosity of the capillaries. This conclusion was reached by comparing the findings in individuals at risk with the results of examination of five patients seen during the acute phase of L.O.N. One of the persons at risk, who had many early signs, developed L.O.N. 6 months after being studied. In 7 of 13 carriers abnormalities were observed that resembled those seen in certain individuals at risk.

A large family with hypokalemic periodic paralysis was reexamined after 50 years. Two new cases were found in the third generation and 12 in the fourth generation. This family now includes 28 affected patients in four generations. The reexamination ascertained the presence of permanent muscle weakness (PMW) in all investigated affected sibs. This fact, and the fact that indications of the presence of PMW without paralytic attacks were found in only one subject, is strong evidence that both are manifestations of the same more or less fully penetrant dominant gene. A linkage study in this family could not localize the gene on the human genome, but close linkage with 25 genetic marker systems could be excluded.

A genetic linkage study was performed in a large Dutch kindred with erythrokeratodermia variabilis (EKV, McKusick no. 13320). The autosomal-dominant trait appeared to segregate rather consistently with the cde (r) gene complex of the Rh system. Only one recombinant was found amongst 27 informative individuals. Lod score calculations gave strong evidence for close linkage between the loci for EKV and Rh (with a maximum lod score of 5.55 at a recombination fraction of 0.044).

Five affected males in the fifth generation of a large pedigree of X-chromosomal incomplete achromatopsia were tested. All had SWS cone function. A 19-year-old affected man was a classical blue cone monochromat on color matching and spectral sensitivity. A 16-year-old boy showed evidence of a long wavelength sensitive cone active in 8 degrees color matches. With a blue-green background, his cone spectral sensitivity function peaked near 550-560 nm. Three younger boys, aged 7-10 yrs were evaluated only with color matching. All showed evidence of long wavelength cone function with an 8 degree field and one showed long wavelength cones in 2 degree matches. An independent observation concerning the family was the finding that deuteranomaly was introduced in the third generation. The fourth generation women, all obligate carriers of X-linked achromatopsia, had a 0.5 chance to carry deuteranomaly. Neither carrier state per se is usually associated with expression of deuteranomaly. Three of the five tested expressed deuteranomaly. This finding of deuteranomaly in the carrier females might be a consequence of a double carrier state indicating association between the genes for deuteranomaly and X-linked achromatopsia.

There have been reports that juvenile onset Huntington's chorea is almost always inherited from the father, and that late-onset Huntington's chorea is inherited more often from the mother than from the father. In this larger survey of the parental transmission of disease in Huntington chorea 12 of 13 patients whose symptoms began before the age of 10 years had inherited the disease from the father. However, the 205 patients with late-onset disease (those who had lived up to at least the age of 65) were as likely to have inherited their disease from their father as from their mother.

Eleven patients belonging to two generations of a Dutch family with cerebral and cerebellar haemorrhage, haemorrhagic infarction and infarction are described. Their ages varied from 44 to 58 years. The principal clinical characteristics was recurring cerebral haemorrhages, sometimes preceded by a history of migrainous headaches or mental changes. In 4 of the 6 autopsied cases, old and new multiple cerebral haemorrhagic infarcts and infarcts were found, in one case a single cerebral haemorrhage and in another a cerebellar haemorrhage. In 5 cases this resulted in secondary subarachnoid haemorrhage. In one case the infarcts were only slightly haemorrhagic and did not result in subarachnoid haemorrhage. This patient presented as dementia. Microscopically, in these 6 cases and in one biopsy specimen hyaline thickening of the walls of cortical arterioles was found. The arteries of the arachnoid showed marked tortuosity, concentric proliferation, and focal hyalinization of the walls. Amyloid was found in the hyalinized vessels in 5 cases, but not outside the central nervous system. We believe that we are dealing with an inherited disorder with an autosomal dominated mode of inheritance, in which microangiopathy leads to cerebral haemorrhage and (haemorrhagic) infarction. It seems likely that amyloidosis underlies the angiopathy, and that this family suffers from a condition similar to the one described by Gudmundsson in 1972.

We evaluated color matching in 39 observers with an autosomal dominant tritan defect. Eleven tritans were dichromats with 1 degrees field, and only two were dichromats with an 8 degrees field. Twenty-one of the tritan observers ahd normal blue-green equations with an 8 degrees field, indicating that autosomal dominant tritans have short-wavelength-sensitive cones. Some of the tritan observers showed a shifted blue-green equation, which was ascribed to rod activity.

Virtually all protoporphyrin in erythrocytes of patients with erythropoietic protoporphyria is bound to hemoglobin. The maximum of the fluorescence excitation spectrum of this protoporphyrin-hemoglobin complex shifted, with increasing concentration, from 405 nm to 389 nm. A similar shift was observed when titrating a solution of free protoporphyrin with hemoglobin. The Soret maximum of free protoporphyrin itself, on the other hand, was not concentration-dependent. These observations indicate that spectrofluorometric measurements do not allow conclusions concerning the mode of protoporphyrin binding to hemoglobin. Experiments on protoporphyrin exchange between the hemoglobins A, F and S reinforced the previously drawn conclusion that protoporphyrin is bound to hemoglobin at the heme-binding sites.

Fluorescein angiography was performed in 71 persons at risk to develop Leber's Optic Neuropathy (L.O.N.), in 10 females carriers of this disease and in 5 patients during the acute phase. The examination was performed in three university eye clinics. The angiograms were randomly mixed with an equal number of 'controls' and reviewed in a blind fashion on two occasions by two observers. A scoring system was developed on the basis of the peripapillary microvascular changes known to occur in the acute phase of L.O.N. All 5 patients could be recognised in this manner. In the pictures of one of the clinics, which were of good quality, a significant difference in scoring between the at risk and control groups appeared to exist. The results suggest that carriers also may have the same fluorescein angiographic abnormalities. One man from the at risk group who obtained high abnormal scores-identical to patients in the acute phase-developed L.O.N. 6 months later.

The study of six families with dominant optic atrophy (DOA) originating from the neighbourhood of Leiden revealed that four could be connected through a common ancestor. A detailed analysis of 89 patients permitted a subdivision of the three remaining families into two groups: one with on the average a low visual acuity (less than 0.1) and the other with a moderately reduced visual acuity (+/- 0.35). Furthermore, differences in colour vision were observed. Genetic heterogeneity is thought to be at the root of these differences.

By screening 27 hypercalcaemic and 21 normocalcaemic subjects in a large Dutch pedigree with familial benign hypercalcaemia (FBH; McK. No. 14598) (McKusick 1983) for more than 35 genetic markers, it was found that linkage of FBH can be excluded at about 25 centimorgans (cM) from GM, 20 cM from ABO, 15 cM from MNS and HLA, 10 cM from JK and PI, and 5 cM each from ACP1, AK1, ADA, GPT1, and PGP.