Renal vascular abnormalities in Bardet-Biedl syndrome

The progress in understanding and treatment of diabetic retinopathy

Diabetic retinopathy is the most frequently occurring complication of diabetes mellitus and remains a leading cause of vision loss globally. Its aetiology and pathology have been extensively studied for half a century, yet there are disappointingly few therapeutic options. Although some new treatments have been introduced for diabetic macular oedema (DMO) (e.g. intravitreal vascular endothelial growth factor inhibitors ('anti-VEGFs') and new steroids), up to 50% of patients fail to respond. Furthermore, for people with proliferative diabetic retinopathy (PDR), laser photocoagulation remains a mainstay therapy, even though it is an inherently destructive procedure. This review summarises the clinical features of diabetic retinopathy and its risk factors. It describes details of retinal pathology and how advances in our understanding of pathogenesis have led to identification of new therapeutic targets. We emphasise that although there have been significant advances, there is still a pressing need for a better understanding basic mechanisms enable development of reliable and robust means to identify patients at highest risk, and to intervene effectively before vision loss occurs.

Advances in our understanding of diabetic retinopathy

Diabetic retinopathy remains the most common complication of diabetes mellitus and is a leading cause of visual loss in industrialized nations. The clinicopathology of the diabetic retina has been extensively studied, although the precise pathogenesis and cellular and molecular defects that lead to retinal vascular, neural and glial cell dysfunction remain somewhat elusive. This lack of understanding has seriously limited the therapeutic options available for the ophthalmologist and there is a need to identify the definitive pathways that initiate retinal cell damage and drive progression to overt retinopathy. The present review begins by outlining the natural history of diabetic retinopathy, the clinical features and risk factors. Reviewing the histopathological data from clinical specimens and animal models, the recent paradigm that neuroretinal dysfunction may play an important role in the early development of the disease is discussed. The review then focuses on the molecular pathogenesis of diabetic retinopathy with perspective provided on new advances that have furthered our understanding of the key mechanisms underlying early changes in the diabetic retina. Studies have also emerged in the past year suggesting that defective repair of injured retinal vessels by endothelial progenitor cells may contribute to the pathogenesis of diabetic retinopathy. We assess these findings and discuss how they could eventually lead to new therapeutic options for diabetic retinopathy.

Refractive errors and strabismus in children with laurence-moon-biedl syndrome

PURPOSE

To describe the ocular and refractive findings in patients with Laurence-Moon-Biedl syndrome.

METHODS

Seventeen patients with Laurence-Moon-Biedl syndrome were evaluated retrospectively. All children underwent complete ophthalmologic examination.

RESULTS

Of the patients evaluated, 88.2% had an ocular or refractive finding, 58.8% had myopia (degenerative in three cases), 52.9% had astigmatism, 11.7% had an-isometropia, 17.6% had strabismus, 11.7% had retinitis pigmentosa, 5.9% had keratoconus, 5.9% had optic atrophy, and 5.9% had nystagmus.

CONCLUSION

Early and regular ophthalmologic assessment is required to prevent visual loss as a result of amblyogenic factors in children with Laurence-Moon-Biedl syndrome.

Cerebellar vermis hypoplasia in a patient with Bardet-Biedl syndrome

Laurence-Moon-Bardet-Biedl syndome is an autosomal recessive condition characterized by retinal dystrophy, obesity, mental retardation, distal limb anomaly, hypogonadism, and renal dysfunction. The symptoms vary among families and even among affected siblings. Certain clinical signs have been used to identify subgroups of patients with this complex condition. Laurence-Moon syndrome as a distinct entity is rare and features paraplegia in the absence of polydactyly or obesity. Bardet-Biedl syndrome is characterized by distal limb anomaly, obesity, and renal involvement, but neurologic symptoms are very unusual. We report a patient exhibiting characteristic features of Bardet-Biedl syndrome in addition to cerebellar vermis hypoplasia and mega cisterna magna.

A review of the literature of Bardet-Biedl disease and report of three cases associated with metabolic syndrome and diagnosed after the age of fifty

Bardet-Biedl syndrome (BBS) is a genetic autosomal-recessive disease (formerly grouped with Laurence-Moon-Biedl syndrome but considered today as a separate entity) characterized by abdominal obesity, mental retardation, dysphormic extremities (syndactyly, brachydactyly or polydactyly), retinal dystrophy or pigmentary retinopathy, hypogonadism or hypogenitalism (limited to male patients) and kidney structural abnormalities or functional impairment. The expression and severity of the various clinical BBS features show inter- and intrafamilial variability. This study focuses on three cases of familial BBS--two sisters and one brother (66, 64 and 51 years of age, respectively)--with the main cardinal findings of the disease plus a classic 'metabolic syndrome' (characterized by abdominal obesity, atherogenic dyslipidaemia, raised blood pressure, insulin resistance with or without glucose intolerance, and prothrombotic risk and proinflammatory states). One female patient (not affected by reproductive dysfunction) had three healthy offspring, while the other two patients were unmarried. Another severely affected brother died at 70 years of age; two other brothers are lean but affected by nephropathy, retinopathy, slight mental retardation, polydactyly, hypertension and thrombotic diseases, and had healthy offspring. BBS is a rather rare but severe syndrome that is often mis- or undiagnosed. Ophthalmologists, endocrinologists and nephrologists should be aware of BBS because of its adverse prognosis--early onset of blindness, associated findings of metabolic syndrome and increased vascular risk, and severe renal impairment (the most frequent cause of reduced survival and death early in life).