Brief report: reverse mutation in myotonic dystrophy

Article Abstract:

Two case studies of reverse mutations in families with myotonic dystrophy are presented. Myotonic dystrophy is a hereditary, multisystem disorder characterized by muscle weakness, wasting, cataracts and heart disturbances. The gene mutation responsible for myotonic dystrophy has recently been identified. In Family 1, the fetus of a healthy mother and a father with myotonic dystrophy had inherited the mutation from her father. However, upon further DNA analysis, the abnormal chromosome in the fetus appeared to have undergone a complete, spontaneous correction of the mutation. A healthy baby girl was born. In Family 2, an asymptomatic 25-year-old man had inherited the mutation from his father. Again, the affected gene had reverted. Reverse mutation has not previously been observed in humans, but has been reported in studies of bacteria and laboratory cultures of mammalian cells. The instability of the abnormal gene may explain the reversion.

Case studies, Mutation (Biology), Mutation, Familial diseases, Myotonic dystrophy

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Prader-Willi syndrome and Angelman syndrome in cousins from a family with a translocation between chromosomes 6 and 15

Article Abstract:

Prader-Willi syndrome and Angelman syndrome are genetic disorders caused by a defect in chromosome 15, but in Prader-Willi syndrome, the defective chromosome is inherited from the father, while in Angelman syndrome, it is inherited from the mother. Every individual has 23 pairs of chromosomes; one in each pair is inherited from the father (the paternal chromosome), and one from the mother (the maternal chromosome). Genetic analysis of a patient with Prader-Willi syndrome showed that her paternal chromosome 15 had a large section missing, including the area thought to contain the Prader-Willi gene. One of her first-degree female cousins had Angelman syndrome, and genetic analysis showed that she had inherited both copies of chromosome 15 from her father. This patient had Angelman syndrome because she had no maternal chromosome 15, which is thought to contain the Angelman syndrome gene.

Genetic disorders, Prader-Willi syndrome

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Precocious puberty in boys

Article Abstract:

In boys and girls, puberty begins when the brain produces a hormone that causes the pituitary gland to produce luteinizing hormone and follicle stimulating hormone. In boys, luteinizing hormone stimulates the production of the male sex hormone testosterone by the testis. A gene mutation may prematurely activate this system, causing premature puberty. A 1999 report described three boys with premature puberty who had a testicular tumor caused by a mutation in the gene for the luteinizing hormone receptor.

Health aspects, Editorial, Causes of, Testicular cancer, Precocious puberty

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