Woodhouse-Sakati
Woodhouse-Sakati Syndrome is caused by a mutation in the DCAF17 gene. It has been described in approximately 30 patients from Middle Eastern families, one Caucasian woman and three siblings from an Indian family. A founder mutation accounts for the cases in the Middle Eastern population.
Clinical Diagnosis
T-2 weighted MRI views of the brain indicating iron accumulation, along with the features of hair loss, diabetes, hearing loss, gonadal dysfunction and intellectual disability are indicative of this syndrome. The onset is usually in adolescence.
It is a multisystemic disorder characterized by hypogonadism, alopecia (hair loss), diabetes mellitus, intellectual deficit and extrapyramidal signs with dystonia ( involuntary muscle cramping that may force certain body parts into unusual, and sometimes painful, movements and positions) and choreoathetosis (a condition characterized by involuntary, rapid, jerky movements (chorea) occurring in association with relatively slow, sinuous, writhing motions (athetosis).
Additional manifestations may include sensorineural deafness, which is a type of hearing loss in which the root cause lies in the vestibulocochlear nerve (cranial nerve VIII), the inner ear, or central processing centers of the brain. Sensorineural hearing loss can be mild, moderate, or severe, including total deafness.
Also seen are flattened T waves on an ECG, seizures, sensory polyneuropathy, and dysarthria (poor articulation and slurring).
There may be various craniofacial abnormalities such as a high forehead, flat occiput, triangular face, prominent nasal root, hypertelorism which is an abnormally increased distance between the eyes, and down-slanting palpebral fissures.
Scoliosis, hyperreflexia (overactive or over responsive reflexes), and camptodactyly which involves the fixed flexion deformity of the interphalangeal joints of the little finger are also seen.
Genetics
Woodhouse-Sakati Syndrome is inherited in an autosomal recessive manner. Because most of our genes exist in pairs (one coming from the mother and one coming from the father), we normally carry two working copies of each gene. When one copy of a recessive gene has a change (mutation) in it, the person should still have normal health. That person is called a carrier.
Recessive diseases only occur when both parents are carriers for the same condition and then pass their changed genes on to their child. Statistically, there is a one in four chance that two carriers would have an affected child. There is a two in four chance the parents will have a child who is also a carrier. The chances are one in four that the child will not have the gene mutation. Carrier testing for at-risk relatives and prenatal testing for pregnancies at risk are suggested if both disease-causing mutations have been identified in an affected family member.
Prenatal Testing
If the disease-causing mutations have been identified in the family, prenatal diagnosis for pregnancies at increased risk can be done. In one test, DNA is extracted from fetal cells obtained by amniocentesis, usually at 15 to 18 weeks’ gestation, and analyzed. Or, sampling is done of the chorionic villus, the tiny finger-like projections on the edge of the placenta, usually at 10 to 12 weeks’ gestation.
Embryo screening, known as preimplantation genetic diagnosis, may be an option for some families in which the disease-causing mutations have been identified.
