Sex Linked Diseases
Acid Maltase Deficiency: It is an autosomal recessive disorder, in which the defect is in the gene for the acid maltase enzyme, which leads to accumulation of glycogen stored in muscles. Glycogen build up, weakens the muscles of a patient suffering from this disorder. This may affect respiratory muscles resulting in respiratory failure. It is also known as the Pompe Disease. Although, in childhood and adolescence the symptoms show slow progress and are less severe, infantile forms cause death within first year, if not treated on time.
Albinism: Albinism is a congenital disorder in which there is little or completely no production of melanin in hair, skin and iris of the eyes. Hence albinos (people suffering from albinism) have light colored skin, hair and eyes. It is caused due to inheritance of recessive alleles from parents. This disorder can’t be cured. However, the symptoms can be alleviated with the help of surgical treatment, vision aids and using device that provide protection from sun.
Alzheimer’s Disease: Alzheimer’s disease is the most common form of dementia which is characterized by gradual memory loss, irritability, mood swings, confusion and language breakdown. Although, scientists are not unequivocal about the cause of this disease, the most widely accepted reason is the amyloid cascade hypothesis, that suggests excess production of a small protein fragment called ABeta (A? ). Also known as Senile Dementia of the Alzheimer Type (SDAT) or simply Alzheimer’s, this is a degenerative disease and scientists are yet to find its cure.
However, balanced diet, mental exercises and stimulation are often suggested for prevention and managing of the disease. Angelman syndrome: It is a neurological disorder that was first described by a British pediatrician, Dr. Harry Angelman, in 1965. This disorder is marked by intellectual and developmental delays, severe speech impairment and problems in movement and balance, recurrent seizures and small heads. Children with Angelman syndrome typically have a happy demeanor. They are hyperactive with short attention span and show jerky hand movements.
These children appear normal at birth. This genetic disorder in human is a classical case of genetic imprinting, in which the disorder is caused due to deletion or activation of the maternally inherited chromosome 15. Its sister syndrome is the Prader-Willi syndrome in which there is a similar loss or inactivation of the paternally inherited chromosome 15. Bardet-Biedl Syndrome: It is a pleiotropic recessive genetic disorder that is characterized by obesity, polydactyly, deterioration of rod and cone cells, mental retardation and defect in the gonads and kidney disease.
It is difficult to diagnose Bardet-Biedl Syndrome, specially in the young. As no cure is yet known for the disorder, treatment is concentrated on specific organs and systems. Barth Syndrome: A rare but serious sex linked genetic disorder, the Barth syndrome is caused due to mutations or alterations in the BTHS gene. The gene is located on the long arm of X chromosome. This disorder primarily affects the heart. Besides heart defects, Barth syndrome results in poor skeletal musculature, short stature, mitochondrial abnormalities and deficiency of white blood cells.
There is no cure for this disorder. Treatment focuses on managing the symptoms and preventing infections. Bipolar Disorder: Also known as manic depressive disorder or bipolar affective disorder, individuals suffering from bipolar disorder suffer from highly elevated moods, referred to as mania or episodes of severe depression. Research shows that both genetic as well as environmental factors are responsible for this disorder. Medicines as well as psychotherapy is found to be useful in dealing with the severe mood swings associated with the disorder.
Jackson-Weiss Syndrome: It is an autosomal dominant genetic disorder in which there are foot abnormalities, and premature fusion of bones in the skull lead to deformations of the facial features (widely spaced eyes, bulging forehead) and the skull. In this syndrome, the great toes are short and wide and turn away from the rest of the toes. Some toes may be fused or have some other abnormalities. The mutation is caused in the FGFR2 gene which is located in chromosome 10. Treatment involves corrective surgery for deformed bones in face and foot.
Klinefelter Syndrome: It is the most common sex linked genetic disorder. In which males have an extra X chromosome. Hence ,this disorder is also known as 47, XXY or XXY syndrome. The most common symptom is infertility. Besides this, males with the XXY syndrome have impaired physical, language and social developments. As these individuals produce less testosterone than other males, such teenagers may be less muscular and have less facial hair than their peers. The presence of the extra X chromosome can’t be undone.