Familial hereditary nephropathy (Alport's syndrome)

Lenticonus anterior and Alport's syndrome

Six patients, from five families, five males and one female, suffering from lenticonus anterior are presented. Furthermore, all suffered from chronic nephritis and nerve deafness and must be considered cases of Alport's syndrome. As all cases with lenticonus anterior which have been published within the last 13 years likewise were affected with nerve deafness and/or chronic nephritis, the assumption is submitted that lenticonus anterior exists exclusively as a part of Alport's syndrome. It is pointed out that four patients had a weakened bilateral macula reflex with changes in pigmentation. Attention is drawn to the fact that patients with lenticonus anterior often have a cornea astigmatism of 2-3 D. A complete table of all reported patients with anterior lenticonus is presented.

The use of ocular abnormalities to diagnose X-linked Alport syndrome in children

The diagnosis of X-linked Alport syndrome is often difficult, but the demonstration of lenticonus and retinopathy may facilitate the diagnosis in adult patients. The aim of this study was to determine the diagnostic usefulness of ocular examination in children. Fourteen families with at least one affected child were studied clinically, and COL4A5 mutations were determined. The families included 15 affected boys (median age 11 years, range 4-19 years). Two boys (13%) had renal failure, nine (60%) had a known hearing loss, one (7%) had lenticonus and five (33%) had a central (4/15, 27%) or peripheral (4/14, 29%) retinopathy. Lenticonus and retinopathy were first noted in 14 and 11 year olds, respectively. All boys with retinopathy had a hearing loss. The early onset retinopathy was associated with a severe mutation (Q1383X). Eight families (8/14, 57%) comprised only sons and mothers, and two mothers (2/12, 17%) had the retinopathy. Six boys (40%) would have been diagnosed with Alport syndrome on the basis of their own or their mother's ocular examinations. None of the six girls (median age 8 years, range 7-14 years) had ocular abnormalities. Hearing loss is usually highly sensitive for the diagnosis of Alport syndrome, but ocular examination of boys and their mothers at the initial consultation is a non-invasive test that is helpful in up to 40% cases.

Alport syndrome. A review of the ocular manifestations

Alport syndrome has a prevalence of 1/5000, and 85% of patients have the X-linked form, where affected males develop renal failure and usually have a high-tone sensorineural deafness by the age of 20. The typical ocular associations are a dot-and-fleck retinopathy which occurs in about 85% of affected adult males, anterior lenticonus which occurs in about 25%, and the rare posterior polymorphous corneal dystrophy. The retinopathy and anterior lenticonus are not usually demonstrated in childhood but worsen with time so that the retinal lesion is often present at the onset of renal failure, and the anterior lenticonus, later. The demonstration of a dot-and-fleck retinopathy in any individual with a family history of Alport syndrome or with end-stage renal disease is diagnostic of Alport syndrome. The presence of anterior lenticonus or posterior polymorphous corneal dystrophy in any individual is highly suggestive of the diagnosis of Alport syndrome. Additional ocular features described in X-linked Alport syndrome include other corneal dystrophies, microcornea, arcus, iris atrophy, cataracts, spontaneous lens rupture, spherophakia, posterior lenticonus, a poor macular reflex, fluorescein angiogram hyperfluorescence, electrooculogram and electroretinogram abnormalities, and retinal pigmentation. All mutations demonstrated to date in X-linked Alport syndrome have affected the COL4A5 gene which encodes the alpha 5 chain of type IV collagen. This protein is probably common to the basement membranes of the glomerulus, cochlea, retina, lens capsule, and cornea. However, the alpha 3(IV) and 4(IV) as well as the alpha 5(IV) collagen chains are usually absent from the affected basement membranes, because the abnormal alpha 5(IV) molecule interferes with the stability of all three. The loss of these collagen molecules from the affected basement membranes results in an abnormal ultrastructural appearance. The ocular and other clinical features of autosomal recessive Alport syndrome are identical to those seen in X-linked disease, while retinopathy and cataracts are the only ocular abnormalities described in the rare autosomal dominant form of Alport syndrome. There are no ocular associations of thin basement membrane disease which is a common disease that probably represents the heterozygous expression of X-linked or autosomal recessive Alport syndrome.

Clear lens extraction and intraocular lens implantation in a patient with bilateral anterior lenticonus secondary to Alport's syndrome

We describe bilateral phacoemulsification and implantation of foldable silicone intraocular lenses in a 25-year-old woman with Alport's syndrome and severe anterior lenticonus. Contrary to previous reports of lens capsule fragility in Alport's syndrome, this patient had relatively tough capsules, as do most patients her age. Apart from the tough capsules and positive pressure, which required the use of a viscoelastic to maintain the anterior chamber, the surgeries were unremarkable. The patient achieved excellent visual and refractive results.

Posterior polymorphous dystrophy and Alport syndrome

Seventeen Thai patients from nine families with Alport syndrome underwent complete ocular examination and specular microscopy. Fourteen (82.3%) patients had ocular changes. Eleven (64.7%) had endothelial vesicles compatible with posterior polymorphous dystrophy. Four of these also had subepithelial opacities, a previously undescribed phenomenon. Other ocular changes included lenticonus and macular and midperipheral retinal flecks. A second group of 18 consecutive patients from 14 families with posterior polymorphous dystrophy detected during routine ocular examination underwent renal evaluation. Five had hematuria, four of whom had sensorineural hearing loss. Two of the four patients also had characteristic renal biopsy findings. Another had sensorineural hearing loss without hematuria, and renal biopsy showed a thin glomerular basement membrane. Posterior polymorphous dystrophy is a common but frequently overlooked finding in Alport syndrome. The frequent association of these two hereditary conditions suggests a common defect in basement membrane formation. Patients with posterior polymorphous dystrophy should be examined for renal abnormalities and hearing loss.

Retinal abnormalities in Alport's syndrome

The ophthalmological findings in 13 patients with Alport's syndrome are reported. Special attention was given to the retina and retinal functions. Flecked retinopathy was present in 12 out of the 13 cases. Two cases showed tortuosity of the retinal vessels. Retinal function tests showed no significant abnormalities. This study suggests that in Alport's syndrome, retinal lesions are more common than has been reported until now.

Genetics of classic Alport's syndrome

41 families with classic Alport's syndrome (hereditary nephritis with sensorineural deafness) were studied. All their pedigrees were compatible with X-linked inheritance. DNA probes were used to investigate genetic linkage in these families. Linkage to probe S21 (DXS17) was confirmed (LOD score = 4.72 at 0 = 0.06), localising the gene for Alport's syndrome to the middle of Xq; thus the disorder is X-chromosomal in nature.

Alport's syndrome

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Ocular changes in some progressive hereditary nephropathies

Ocular involvement is a common feature of three hereditary nephropathies: cystinosis, nephronophthisis and Alport's syndrome. The follow-up of 25 cases of infantile cystinosis over a period of 26 years demonstrated that the corneal and retinal epithelium were affected in the same way as the kidney epithelium. Corneal involvement induced photophobia and discomfort, but actual blindness was mainly due to retinal involvement, and therefore no corneal graft was performed. The use of topical cysteamine appears to be promising, but its production raises many questions so no definitive conclusions may be made. Since 1965, 51 patients with nephronophthisis have had ocular examinations; all patients had characteristic clinical symptoms and histological findings. The first group, which consisted of 18 children, all under 10 years of age, was found to have obvious chorioretinal degeneration. The second group, which consisted of 11 children, had a normal ocular examination and normal electroretinogram (ERG). The third group, consisting of 22 children, had a normal clinical examination but ERG tracings with variable alterations. In 28 instances of Alport's syndrome, two types of ocular abnormalities have been observed. In six cases, an anterior lenticonus was noted, which caused a major decline in visual acuity. Retinopathy, which did not affect vision, was observed in 13 cases.

Alport's syndrome as a cause of renal failure in Europe

We studied the geographical distribution, male to female ratio, and age at the start of renal replacement therapy (RRT) for end-stage renal failure (ESRF) in 600 patients with hereditary nephritis with nerve deafness (Alport's syndrome) reported to the European Dialysis and Transplant Association Registry since 1975. Annual age- and sex-specific acceptance rates for RRT showed a variable peak incidence according to country, ranging between, 0 and 2.4 patients per million population in males aged 15-24 years, but with only about half this incidence in females. In Scandinavian countries there were very few females who started RRT, and males were older than in the rest of Europe. The overall male to female ratio was 4:1. The median age at the start of RRT was: males (n = 479) 24.3 years (1st quartile 19.5 years; 3rd quartile 31.5 years); females (n = 121) 31.5 years (1st quartile 23.0 years; 3rd quartile 43.2 years). Our study provided confirmation that males reach ESRF earlier than females. In addition, we detected previously unrecognized geographical differences.

Hereditary chronic nephritis in India

Forty-six patients from 23 Indian families with hereditary chronic nephritis (HCN) with or without Alport's syndrome are presented. The occurrence of this disease in diverse Indian races, communities and castes is now documented. Clinical and laboratory findings in these patients are similar to those reported from temperate regions.

Ocular manifestations of Alport's syndrome: a hereditary disorder of basement membranes?

The ocular manifestations in 16 patients with Alport's syndrome were lenticonus and retinal flecks in the macula and mid periphery. These 3 features appear to be specific for this syndrome and are a considerable aid to diagnosis. Lens opacities are common, and other ocular abnormalities occur sporadically. The present evidence indicates that this is a hereditary, widespread disorder of basement membrane, and it is suggested that ophthalmologists may contribute to the further understanding of it by directing attention towards analysis of the lens capsule after cataract extraction. The similarity of the retinopathy to that of fundus albipunctatus is noted, and it is suggested that the latter condition should not be diagnosed in the absence of renal investigation and audiometry.

Glomerular basement membrane attenuation in familial nephritis and "benign" hematuria

Lamination of the basement membrane has been considered to be the lesion characteristic of familial nephritis and attenuation to be the lesion of "Benign" familial hematuria. Electron micrographs were reviewed of 57 children who had renal biopsies for persistent hematuria. Attenuation or lamination of the glomerular capillary basement membrane was found in each. Twenty of the 57 children had familial nephritis; 20 had familial hematuria; and 17 had no involved relatives. Follow-up data were available for 14 of 20 children with familial nephritis, 12 of 20 with familial hematuria, and 12 of 17 with sporadic hematuria for 13.6 +/- 6.3, 6.7 +/- 4.6, and 7.0 +/- 4.8 years, respectively, after discovery of hematuria. Five children developed end-stage renal disease: three with familial nephritis, one with familial hematuria, and one with sporadic hematuria. Only two no longer had hematuria. Attenuation of the glomerular capillary basement membrane was seen in every biopsy, whereas lamination was not. Because hematuria and ultrastructural abnormalities were findings shared by all the children, we suggest the possibility that familial nephritis, and familial or sporadic hematuria as defined in this study, may be variations in a spectrum of inherited abnormality or abnormalities in the formation of the glomerular capillary basement membrane.

Retinal lesions in Alport's syndrome

We described a family in which two siblings were suffering from Alport's syndrome. Both had identical ocular lesions: whitish-grey dots in the superficial layers of the retina mainly in the posterior pole. The visual acuity, the visual field, and the fundus fluorescein angiogram were normal. These lesions were associated with an impaired ERG. The ocular finding seems to be characteristic of the Alport's syndrome.

Apparently changing patterns of inheritance in Alport's hereditary nephritis: genetic heterogeneity versus altered diagnostic criteria

With the use of more stringent diagnostic criteria, it has recently been shown that some large pedigrees of Alport's and non-Alport's hereditary nephritis fit sex-linked dominant inheritance (O'Neill et al. 1978). We have used similar diagnostic criteria and have studied a number of Michigan pedigrees in order to see if this hypothesis would be confirmed. We found one small pedigree which definitely shows male-to-male transmission, while one large pedigree is tentatively compatible with sex-linked dominant inheritance. Many of the other pedigrees suggested male-to-male transmission. This Michigan experience is compared to other published reports and found to be consistent, although a trend of fewer reports of male-to-male transmission is seen. We conclude that genetic heterogeneity of Alport's hereditary nephritis is likely.

Lenticonus in Alport's syndrome. A family study

A South Indian family with three well documented cases of Alport's syndrome with anterior lenticonus are reported. Clinical features of the syndrome including ocular and laboratory findings have been presented and discussed. Macular pigmentation, 5 cases, subcapsular opacity and nephrotic syndrome, one case each, observed in the present series are of great interest and are quite rare in patients with Alport's syndrome. Critical analysis of the family pedigree revealed autosomal dominance with incomplete penetrance as the possible mode of genetic transmission of the disease.

Hereditary nephritis, deafness and abnormal thrombopoiesis. Study of a new kindred

A fourth kindred displaying the triad of hereditary nephritis, deafness and thrombocytopenia with giant platelets is described. Renal involvement, a common cause of death amongst afflicted subjects, appears to have a better prognosis in the affected members of this family. Although the electron microscopic appearance of the megakaryocytes in the present case appears similar to that in previously reported cases, we suggest that the "giant" platelets may result from a degenerative process of megakaryocytes leading to nuclear regression and cytoplasmic fragmentation, rather than the usual blebbing process.