Clinical genetics
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Review Case Reports
The inheritance of conotruncal malformations: a review and report of two siblings with tetralogy of Fallot with pulmonary atresia.
Congenital heart defects (CHD) are a group of structural abnormalities that in humans have a combined incidence of approximately 1%. It is estimated that 4-5% of CHD are associated with chromosome abnormalities, 1-2% are associated with single gene syndromes, 1-2% are due to known teratogens, with the rest presumably determined multifactorially. ⋯ We feel the small number of family clusters and the rare instances of consanguinity in non-syndromal conotruncal defects are consistent with multifactorial determination. While it is prudent in counseling families with 2 or more individuals with conotruncal CHD to raise the possibility of single gene inheritance, we believe that current empiric recurrence risk estimates most accurately reflect their risks.
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The common fragile site on the end of the long arm of the human X chromosome has been shown to be at a different location from the rare fragile site which produces the fragile X syndrome of intellectual handicap. The different locations can be clearly seen in chromosomes at about the 550 band level of resolution. This finding should help resolve difficulties in fragile X cytogenetics where expression of the common fragile site can lead to false positive diagnoses.
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The presence of skin cancer was investigated in 111 albinos belonging to the black (Negro) population of Johannesburg, South Africa. The overall rate was 23.4%, the risk increasing with age. ⋯ No melanomas were detected. Recommendations are made regarding prevention of skin cancer in the at-risk group.
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Bloom's syndrome has been known as a clinical entity for 34 years. Careful records of cases diagnosed throughout the world have been maintained since its recognition as an entity, and most instances of cytologically verified Bloom's syndrome have been accessioned to what has been referred to as the Bloom's Syndrome Registry since the mid-1960s. ⋯ In the 130 persons in the Registry, 57 malignant neoplasms had been detected, the mean age at diagnosis being 24.8 years. Neoplasia in Bloom's syndrome is noteworthy not only because of its frequency and exceptionally early age of emergence but for its variety of histological types and sites of origin.
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The autosomal recessive multiple pterygium syndromes are a heterogeneous group of disorders in which multiple joint contractures are associated with cutaneous webbing. Recently, we evaluated a 33 week gestation male in whom multiple pterygia were one feature of a broader pattern of malformation. ⋯ In this report we present the clinical, radiographic and pathologic data of this patient and those of an affected stillborn female sibling. We believe that these represent the features of a newly recognized disorder.