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Biomedical subjects

D B van Dorp

Publications and source records attributed to D B van Dorp.

15 recordsLinked to original sources
PubMed1992

A family with RP3 type of X-linked retinitis pigmentosa: an association with ciliary abnormalities.

The results of linkage analysis in a family with X-linked retinitis pigmentosa (XLRP) are presented. Probe M27B (DXS255), localized to Xp11.22, was only loosely linked to XLRP, whereas pHOC3 (OTC), in the more distal Xp21.1 region, was tightly linked. In this family, the conditional probability of an RP3 locus (in Xp21.1-p11.4) was found to be 0.978 compared with 0.021 for an RP2 locus (in Xp11.4-p11.2). Risk assessment showed that 2 out of 4 "at risk" females showing no clinical abnormality have a high probability of being genetic carriers of XLRP. Some affected males have recurrent respiratory infections as a result of a condition indistinguishable from the immotile cilia syndrome; indeed, there is an association between XLRP and susceptibility to respiratory infections in the majority of affected males. The possibility that previously observed ciliary abnormalities in XLRP patients might be associated specifically with an RP3 locus abnormality is discussed.

Ciliary Motility Disorders↗
PubMed1992

Carrier detection in X-linked ocular albinism of the Nettleship-Falls type by DNA analysis.

X-linked ocular albinism (XOA) is characterized by anomalies of the eyes and hypopigmentation or absence of pigment in skin, hair and eyes due to a hereditary inborn error of metabolism affecting the pigment cells. The gene of XOA of the Nettleship-Falls type (OA1) has been mapped to Xp22.3, and several closely linked RFLP loci have been identified. Linkage analysis and deletion mapping have established the marker gene order Xpter-STS-DX237-(OA1,DXS143,DXS85)-DXS1 6-DXS43-Xcen. Although the position of OA1 has yet not been fully resolved, we report on the first carrier detections in OXA of the Nettleship-Falls type by DNA analysis using markers which unquestionably flank OA1.

Albinism, Ocular↗
PubMed1991

Joubert syndrome: a clinical and pathological description of an affected male and a female fetus from the same sibship.

A severely retarded male child with Joubert syndrome is described. He had severe neurological anomalies including Dandy-Walker malformation, hypoplasia of the corpus callosum, occipital meningo-encephalocele, and bilateral coloboma of the optic nerve with retrobulbar cystic mass. This is the first male described so far with both coloboma and other midline defects. A detailed autopsy on an affected female fetus from the mother's second pregnancy is presented.

Abnormalities, Multiple↗
PubMed1991

Multipoint linkage analysis in X-linked ocular albinism of the Nettleship-Falls type.

An extensive linkage analysis was performed by studying ten Xp22 loci in ten families segregating for X-linked ocular albinism of the Nettleship-Falls type (XOA). Linkage was confirmed between the XOA locus (OA1) and both DXS16 (theta max = 0.10, zeta max = 4.09) and DXS237 (theta max = 0.12, zeta max = 2.53). Linkage was found between OA1 and the loci DXS85 (theta max = 0.00, zeta max = zeta max = 4.37), DXS143 (theta max = 0.04, zeta max = 3.74), STS (theta max = 0.05, zeta max = 2.48), DXF30S1 (DXS278) (theta max = 0.07, zeta max = 8.79) and DXF30S2/3 (DXS278) (theta max = 0.00, zeta max = 14.93). An indication for linkage was found between OA1 and the loci DXS43 (theta max = 0.10, zeta max = 1.58) and DXS31 (theta max = 0.12, zeta max = 1.55). The analysis of multiple informative meioses suggests the order Xpter-(DXS31, DXS89)-(DXF30S1, DXS237)-(DXF30S2/3, OA1)-DXS143-(DXS16, DXS43)-Xcen. Various multipoint linkage analyses using the DNA loci order DXF30S1-STS-DXS237-DXS143-DXS16 significantly favour the position of OA1 between DXS237 and DXS143. These results further determine the genetic map around the XOA locus on the distal Xp and may be useful for DNA diagnosis in families with XOA.

Albinism, Ocular↗
PubMed1990

Tuberous sclerosis. Diagnostic problems in a family.

This paper describes a family in which the first child, a girl born in 1988, has tuberous sclerosis (TS). The 28-year-old mother had no symptoms of TS but at ocular examination she presented with progressively increasing prominence of the optic nerve heads with a few glistening spots due to deep and superficial drusen, and tilted disks. Visual fields showed enlarged blind spots. Fluorescein angiography showed lobular drusen of the optic nerve heads. The ERG showed an absent B-wave. The family history was negative for TS. The question arises whether these ocular findings have to be interpreted as part of the syndrome of TS. In that case the recurrence risk for the disease is 50% for each next child. Assuming a spontaneous mutation in the first child, however, the risk can be nearly neglected. Until the genetic defect in TS is found, these problems in genetic counselling of parents with a child with TS will remain unsolved. Prenatal diagnosis by DNA-analysis is not yet possible; however a few cases of TS have been diagnosed prenatally by fetal ultrasonography of the heart, as was the case in the affected child.

Adult↗
PubMed1989

Hermansky-Pudlak syndrome: correction of bleeding time by 1-desamino-8D-arginine vasopressin.

The effect of the synthetic vasopressin derivative 1-desamino-8D-arginine vasopressin (DDAVP = desmopressin) on bleeding time was studied in three patients with Hermansky Pudlak syndrome. A good response was observed in this type of storage pool disease. DDAVP might be useful in managing the bleeding disorder found in patients with the Hermansky-Pudlak syndrome.

Adolescent↗
PubMed1987

Albinism, or the NOACH syndrome (the book of Enoch c.v. 1-20).

UNLABELLED: After a 4-year multidisciplinary study of albinism our findings will be presented here. Over a hundred albinos were examined, together with their heterozygote family members. Given this substantial patient and subject sample we were provided with the opportunity to: evaluate the results of standard diagnostic procedures, for example pedigree analysis, ocular and clinical examination; determine the diagnostic value of biochemical, and ultrastructural tests; and develop a new and viable albino diagnostic protocol, particularly for electrophysiological examination. In the conclusions the following subjects are in order: DIAGNOSIS: Our most important finding up till now is that normally pigmented people who do not look like albinos can in fact be albinos. DIFFERENTIAL DIAGNOSIS: It appears that patients with autosomal recessive albinism can be normally pigmented, and patients with X-linked albinism can be severely hypopigmented. We therefore propose to abandon the terms oculo-cutaneous albinism (OCA), and X-linked ocular albinism (XOA), and use the terms autosomal recessive albinism, and X-linked albinism instead. X-linked albinism Forsius-Eriksson type (XOAF): We assume that XOAF does not represent a true form of albinism. CLASSIFICATION: Our results indicate that the phenotypical albino classification, which was a base for Witkop et al. (1978) to also obtain a genetical classification, supported by the hairbulb test, has not proved to be useful for the classification of tyrosinase negative (TNOCA), tyrosinase positive oculocutaneous albinism (TPOCA), and autosomal recessive ocular albinism (AROA) as genetically distinct forms. Prevalence: Our prevalence estimate for all forms of albinism is at least 1:15,000, about 10% of the albinos have X-linked albinism. DEFINITION: We want to modify the albino definition as a hereditary and congenital inborn error of metabolism related to the pigment cell, and resulting in a systemic disorder that is characterized by anomalies of eyes, and hypopigmentation in most cases or absence of pigment in skin, hair, and eyes, and of which the neuro-anatomical consequences are the most characteristic.

Albinism↗
PubMed1985

[Corneal opacity].

A case with bilateral corneal opacification in the form of a half-ring is described. Routine laboratory tests revealed no abnormalities, and serum lipoprotein composition was normal. The authors suspect that this was a case of primary lipoidal keratopathy.

Adult↗
PubMed1985

Aland eye disease: no albino misrouting.

Electrophysiological studies showed that a patient with Aland eye disease had no misrouting of the optic pathways which is always found in all forms of albinism as a consequence of the retino-geniculate anomaly. Also the spontaneous and optokinetic nystagmus did not resemble that of the large majority of human albinos. The marked asymmetry found in this patient seems to be typical for humans with a defective development of foveal binocular vision. These findings are in agreement with clinical, nystagmographic and EM findings that Aland eye disease is distinct from the Nettleship-Falls type of X-linked ocular albinism. Furthermore, Aland eye disease is different from X-chromosomal congenital stationary night blindness with myopia by the fact that the scotopic functions are only moderately affected and there is no restriction of the peripheral photopic visual fields. In addition, there is latent nystagmus of extraocular type that appears also in female carriers. There is no ophthalmoplegia, there is a progression of the myopia and the dyschromatopsia is of secondary type.

Adult↗
PubMed1985

Fluorescein angiography in potential carriers for choroideremia. An additional aid for final diagnosis, when funduscopy shows equivocal symptoms.

As an extension of a large pedigree with choroideremia, described by Kurstjens in 1965, a family will be presented. A daughter of an affected male presented with her two carrier daughters and her three unaffected sons. In one daughter, funduscopy did not reveal characteristics specific for the diagnosis of the carrier state for choroideremia. Special attention will be paid to the diagnostic value of fluorescein angiography for final diagnosis and genetic counseling.

Adolescent↗
PubMed1983

Albinism: phenotype or genotype?

As part of a combined ophthalmological, genetic, clinical, biochemical, ultrastructural and electro-physiological study of albinism we have examined over one hundred albinos, together with their heterozygote family members. Given this substantial number, we have developed a diagnostic protocol to facilitate albino classification and heterozygote detection. The major difficulty in the detection and differential diagnosis of albinism is that for a given albino, not all symptoms, either ophthalmological or cutaneous, may be manifest, whereas several may be in a non-albino. To compensate for the wide diversity in albino expression, diagnosis is typically based on the results of combinations of tests.

Adolescent↗
PubMedDate not supplied

A family with X-chromosomal recessive congenital cataract, microphthalmia, a peculiar form of the ear and dental anomalies.

An investigation has been made in a family with X-chromosomal recessive congenital cataract, microphthalmia, a peculiar form of the ear, and dental anomalies. The carrier females show only slight symptoms. They all have lens opacities, and most of them show more symptoms. For genetic counseling it is of utmost importance to examine all family members and to re-examine the females from time to time for early lens opacificaiton, which is the most constant finding. In literature families have been described with similar clinical symptoms only a few times. We have been trying to demonstrate a linkage with the Xga locus, which might enable us to locate the mutant gene on the X-chromosome and to exclude with more certainty the carrier status. The results of this blood group specification were not informative. In future we hope to be able to demonstrate a linkage with other markers located on the X-chromosome.

Adolescent↗