Serum Levels of Gonadotrophins in Relation to Multiple Pregnancy in Nigeria

Nylander, P. P. S.

doi:10.1111/j.1471-0528.1973.tb16043.x

Cited by 64 publications

(25 citation statements)

References 8 publications

(1 reference statement)

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“…For seminoma, these comparisons suggested independent effects of both birth order and sibship size, although only the latter, which was stronger, gave significant results. The only previous study examining the risks by birth order allowing for sibship size (Morrison, 1976) Dizygotic twinning may be associated with high maternal gonadotrophin levels (Milham, 1964;Nylander, 1973). On the hormonal hypothesis one might therefore expect that testicular cancer would occur more often in men who were twins.…”

Section: Discussionmentioning

confidence: 99%

Prenatal and familial associations of testicular cancer

Swerdlow¹,

Huttly²,

Smith³

1987

Br J Cancer

106

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Summary In a case-control study of testis cancer 259 cases with testicular cancer, 238 controls treated at radiotherapy centres and 251 non-radiotherapy hospital in-patient controls were interviewed about some possible prenatal .tnd familial risk factors for the tumour. For firstborn men, the risk of testis cancer increased significanlly according to maternal age at the subject's birth, and this effect was most marked for seminoma. The association with maternal age was not apparent for cases other than firstborn. The risk of testis cancer was also significantly raised for men from small sibships and of early birth order. These results accord with the theory that raised maternal levels of available oestrogen during the early part of pregnancy are aetiological for testicular cancer in the son, although other explanations are possible; there is evidence that seminoma risk may particularly be affected.

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Section: Discussionmentioning

confidence: 99%

Prenatal and familial associations of testicular cancer

Swerdlow¹,

Huttly²,

Smith³

1987

Br J Cancer

106

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“…Mothers of spontaneous DZ twins have a higher incidence of multiple ovulations and several studies report an increased concentration of folliclestimulating hormone (FSH) during their menstrual cycle. 15,16 FSH release is controlled by a complex feedback mechanism from the ovary. Genes in the pathway controlling the synthesis, release and activity of FSH are therefore good candidates for increased DZ twinning frequencies.…”

Section: Discussionmentioning

confidence: 99%

Genome-wide linkage scan for spontaneous DZ twinning

et al. 2005

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In humans, spontaneous DZ twinning is known to have a genetic basis. A prior investigation in the Flemish and Dutch population showed that the phenotype of 'having DZ twins' was consistent with an autosomal monogenic dominant model, with a gene frequency of 3.5% and a female-specific lifetime penetrance of 10%. Recessive, X-linked, polygenic and sporadic models were rejected. This study reports on a genomewide scan of 14 Flemish families containing 57 mothers of spontaneous DZ twins. Two-point linkage analysis using the autosomal dominant model showed nine chromosomal regions with a LOD score around 1. After multipoint linkage analysis, including heterogeneity, three chromosomes continued to give high LOD scores. These regions were further haplotyped with additional markers at 1 cM distance. The multipoint analysis was not in favour of linkage of the DZ twinning trait in most candidate genes and other regions (LOD score o À2) under the genetic model of autosomal dominance. To further evaluate the evidence for linkage given some uncertainty about the correct mode of inheritance of twinning susceptibility other models of inheritance were tested. Results of this analysis showed all models gave highest LOD scores under dominant models. If heterogeneity among the families is taken into account, the peaks that were observed on chromosome 2, 7 and 18 could well contain a potential gene contributing to DZ twinning. These results give suggestive evidence that the mode of inheritance of DZ twinning is probably more complex than was originally expected.

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“…Milham (1964) suggested a relation between gonadotropins and dizygotic twinning rate; a high twinning rate is related to a high blood gonadotropin level (Nylander, 1973). Soma et aL (1975) reported significantly lower plasma gonado-tropin levels in Japanese women than in Nigerian women, who, as reported by Nylander (1973), had a high frequency of twinning. Soma et aL (1975) suggested that the low dizygotic twinning rate in Japanese women might be related to their low output of gonadotropin.…”

Section: Discussionmentioning

confidence: 77%

“…Such geographical cline of multiple birth rates in Japan was also seen in dizygotic twinning rates, which was higher in the northeast than in the southeast (Imaizumi and Inouye, 1979). Milham (1964) suggested a relation between gonadotropins and dizygotic twinning rate; a high twinning rate is related to a high blood gonadotropin level (Nylander, 1973). Soma et aL (1975) reported significantly lower plasma gonado-tropin levels in Japanese women than in Nigerian women, who, as reported by Nylander (1973), had a high frequency of twinning.…”

Section: Discussionmentioning

confidence: 82%

Analysis of multiple birth rates in Japan

Imaizumi

Inouye

1980

Jap J Human Genet

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SummaryOver-all triplet birth rate in Japan was decreased during 1955 to 1967 and 1974. Monozygotic rate was slightly decreased with the year, but dizygotic rate as estimated from monozygotic and dizygotic twinning rates was decreased with the year. Trizygotic rate was increased with the year and particularly high in 1974.Monozygotic rate was slightly increased up to the maternal age group of 35-39 years and decreased thereafter. Similar but more marked pattern is seen for dizygotic rate, whereas trizygotic rate seems to be independent of maternal age. Analysis of secular change during the period from 1960 to 1967 indicated a clear decrease of monozygotic rate in the older maternal age groups. The maternal age effect on the increase of trizygotic rate is less clear.The highest monozygotic rate was seen in the northeast Hokkaido District (56 per million). On the other hand, dizygotic rate was slightly higher in the northeast than in the southwest. As to trizygotic rate, the highest rate was seen in the southwest Kyushu District (10 per million). Heterogeneity of geographical variation was indicated in monozygotic and trizygotic rates, but not in dizygotic rate.Underrepresentation of unlike-sexed triplet sets was suggested in two districts. After excluding the two districts, corrected monozygotic rate is 30, and dizygotic and trizygotic rates are 18 and 7 per million, respectively.

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Serum Levels of Gonadotrophins in Relation to Multiple Pregnancy in Nigeria

Cited by 64 publications

References 8 publications

Prenatal and familial associations of testicular cancer

Prenatal and familial associations of testicular cancer

Genome-wide linkage scan for spontaneous DZ twinning

Analysis of multiple birth rates in Japan

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