Specific eye conditions may be a clue to diagnosing Angelman syndrome in patients who also have abnormalities consistent with other diseases, a case report suggests.
The report, “A Case of Fundus Oculi Albinoticus Diagnosed as Angelman Syndrome by Genetic Testing,” was published in Case Reports in Ophthalmology.
Angelman syndrome is a complex disorder characterized by severe developmental anomalies such as convulsions, scoliosis (curvature of the spine), easily induced laughing seizures, ataxic gait, and sleep disorder. Eye problems related to Angelman include discoloration of the inner back portion of the eyeball (fundus oculi albinoticus), poor visual tracking, eye movement abnormality, farsightedness (hyperopia), involuntary eye movement (nystagmus), congestion failure, and absence of the iris (aniridia).
In its case report, a team from Osaka Medical College in Japan described a 4-year-old boy who was born with respiratory and swallowing difficulties.
After birth, a complete physical examination was performed, and an MRI showed abnormal brain development, including a thin corpus callosum, which occurred before birth. The corpus callosum allows communication between the two sides of the brain; anomalies in this area can have serious consequences.
Clinicians also found narrowing of the left and right tubes (ureters), which move urine from the kidneys to the bladder. Swelling of the ureters and kidney were also observed and caused by urine retention.
These conditions, along with heart defects and a light skin tone, led doctors to suspect the boy had Dandy-Walker syndrome, a rare brain malformation present at birth, but that diagnosis fell through.
But genetic disease testing indicated a mutation in the AS gene region, leading to an Angelman diagnosis.
At 1 month of age, the boy had optic atrophy (damage in the optic nerve) and almost no direct light reflex or visual response, and his iris (the colored disc inside the eye) was slightly discolored.
Periodic follow-ups showed no significant changes in either optic atrophy or fundus oculi albinoticus with the development of his eyes. Now, at 4 years old, both eyes have no light reflex and no visual responses, such as visual tracking.
Several of the boy’s brain malformations, however, could have contributed to the eye changes apart from Angelman’s.
This case seems to differ from “those of previous reports due to the merger of numerous brain congenital malformations, such as a thin corpus callosum, fissile brain disease, and polymicrogyria. The relationship between these abnormalities and AS is unknown, and it is highly possible that other genetic abnormalities may be involved,” the researchers wrote.
Nonetheless, these findings suggest that in cases where optic atrophy and discoloration of the iris and inner part of the eyeball are observed together with other malformations, Angelman syndrome should be considered.