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MICROCEPHALY IN THE NETHERLANDS: A CLINICAL AND GENETICAL STUDY
Author(s) -
BOSCH J.
Publication year - 1958
Publication title -
annals of human genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 77
eISSN - 1469-1809
pISSN - 0003-4800
DOI - 10.1111/j.1469-1809.1958.tb01455.x
Subject(s) - microcephaly , consanguinity , incidence (geometry) , population , sex ratio , demography , biology , pediatrics , genetics , medicine , mathematics , geometry , sociology
Summary Data were collected on the incidence, geographical distribution, and genetical aspects of 113 cases of microcephaly in the Netherlands: thirty‐nine cases, or about 34 %, appeared to be of special genetic origin. In the ‘genetic’ material the sex ratio (twenty‐seven boys, twelve girls) appeared to be deviating from the total population ratio of approximately 1:1, but proved to be in accordance with the expectation, 1.56:1, for a population of mentally defective children cared for in institutions in the Netherlands. Consanguinity among the parents of the ‘genetic’ propositi was found in 54 % of the cases. In 23% the parents were first cousins. In 24% no genetical arguments could be shown to exist for the diagnosis ‘special genetic type’. In 24 % the only confirmation on genetical grounds was the existence of more cases in sibship and/or family. The most likely ratio of microcephalic to normal sibs was 0.362, σ= 0.0597. The deviation from the expected ratio in recessivity, 0.25, is 0.112, or 1.88 times the standard deviation, so it seems likely that, in our material, recessive genes are playing an important part. The incidence of special genetic microcephaly is about 1:250,000 in the Netherlands, of all microcephaly about 1:93,000. The difficulties encountered by the investigator are discussed.