Craniotrontonasal syndrome CFNS is a birth detect in which p

Craniotrontonasal syndrome (CFNS) is a birth detect in which premature fusion of the cranial sutures leads to abnormal head shape, widely spaced eyes, nasal clefts, and various other skeletal abnormalities. George Feldman and his colleagues, looked at several families in which CFNS occurred and recorded the results shown in the following table (G. J. Feldman. 1997. Human Molecular Genetics 6:1937-1941). On the basis of the families given, what is the most likely mode of inheritance for CFNS? Autosomal dominant X-linked dominant Autosomal recessive X-linked recessive Autosomal codominant

Solution

It is important that CFNS should be present in order to have a CFNS offspring.As a result it should be dominant.On the other hand we also notice that whenever a father has CFNS then only the daughter got CFNS .This means the CFNS is X-LINKED DOMINANT and it depends on the value of X and its dominant as earlier stated. So this is the answer in the given case.