Älstrom’s syndrome is characterised by dystrophy of the cones (cells that enable daytime vision and colour vision) and rods (cells that enable night vision or vision in dimly lit places) in the retina, the inner eye tissue onto which images are projected and where light signals are converted into electrical impulses that reach the brain and generate vision.

The syndrome is also associated with hearing loss, hypertriglyceridaemia and obesity, hyperinsulinaemia, type 2 diabetes mellitus, dilated cardiomyopathy (DCM), multi-organ fibrosis, hypogonadism/hyperandrogenism, chronic respiratory disease, and progressive renal and hepatic dysfunction.

Cone and rod retinal dystrophy usually has a strong genetic factor and develops within a few weeks after birth, although the form and age of onset of the first symptoms are highly variable between patients. Symptoms include nystagmus (involuntary eye movement) and photodysphoria (high sensitivity to light).

From an ophthalmic perspective, it is a serious eye disease, as it progressively leads to total blindness, usually in adolescence. However, the symptoms, in many cases systemic, go much further, as most patients develop progressive bilateral neurosensory loss of varying intensity, multiorgan fibrosis, obesity, hyperinsulinemia and risk of heart failure.

There is no curative treatment, so the therapeutic objective is based on improving symptoms. As it is a process that affects many organs, it usually involves different specialists who must work in a coordinated manner, including the paediatrician, family doctor, ophthalmologist, endocrinologist, otolaryngologist and cardiologist.

The facial features of these patients are unmistakable: sunken eyes, round face, pronounced ears, premature frontal balding and thinning hair. Most children have broad, thick, flat feet, with short, thick fingers and toes, without polydactyly or syndactyly. Slowly progressive nephropathies, liver dysfunction, chronic respiratory diseases, hypertriglyceridaemia and hypertension are common. Most patients show normal intelligence, although some reports indicate delays in psychomotor and intellectual development.

Alström syndrome is caused by mutations in the ALMS1 gene and is transmitted as an autosomal recessive trait. Diagnosis is made on the basis of observed clinical features, usually without genetic confirmation. The identification of 2 mutated alleles, or the mutated ALMS1, with typical clinical features, would confirm the diagnosis. If ALMS1 mutations are detected in at-risk foetuses, prenatal screening and genetic counselling is advisable.

Its estimated prevalence is 1 case per 1.000.000 inhabitants in Europe and North America, being much higher in certain populations with a high degree of consanguinity or geographically isolated.

The company doing research in the field of this disease is Sylentis.