Objective: The authors report 22 cases of Alström syndrome (AS), which is the largest series to date. Only 37 cases have been reported in the world literature since 1959. The authors review the clinical features and compare these with the overlapping condition of Bardet-Biedl syndrome. Their aim is to clarify the AS phenotype and to increase awareness of the early features.
Design: A retrospective case series.
Participants: All patients (22) with a diagnosis of AS admitted to the authors' hospital in the past 10 years were included in this review.
Intervention: This is principally a review of ocular features, but other features are recorded and discussed.
Main outcome measures: Features noted included age at onset of visual symptoms, presence of photophobia, visual acuity, and electroretinogram findings. Nonocular features recorded included cardiac status, weight and height, hearing, and presence of diabetes mellitus.
Results: Cardiomyopathy presenting in infancy has only been recognized recently to be a feature of AS. Of the authors' cases, 18 of 22 had infantile cardiomyopathy. In the authors' tertiary referral institution, there is an ascertainment bias toward younger patients and especially those with pathology that is other than ocular pathology. In addition, AS is difficult to recognize in childhood without the development of infantile cardiomyopathy. Alström syndrome often is not recognized until diabetes mellitus develops in the second or third decade. Initially, a diagnosis of cone-rod dystrophy, achromatopsia, Leber's congenital amaurosis, or Bardet-Biedl syndrome may be made. In AS, there is a severe infantile retinal dystrophy. The electroretinogram is absent or attenuated with better preserved rod than cone function. The retinal dystrophy is progressive with the patient's visual acuity of 6/60 or less by 10 years of age and no light perception by 20 years of age.
Conclusions: A diagnosis of AS should be considered in infantile cone and rod retinal dystrophy, particularly if the weight is above the 90th percentile (16 of 18 cases) or if there is an infantile cardiomyopathy (18 of 22 cases).