Genetic Prognosis in Severe Mental Handicap

Angeli, Emelia; Kìrman, Brian H.

doi:10.1111/j.1365-2788.1975.tb01271.x

Cited by 9 publications

(5 citation statements)

References 42 publications

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“…Third, our findings of an inverse relation between ID severity and the familial risk estimates are in accordance with older studies on siblings (Angeli & Kirman, 1975;Bundey & Carter, 1974;Durkin et al, 1976). We have observed a similar pattern of inheritance in second-degree relatives.…”

Section: Main Findingssupporting

confidence: 92%

“…There are four main findings from our investigation. First, our 20-years risk and frequency of ID in full-siblings are comparable to old reports (Angeli & Kirman, 1975;Becker et al, 1977;Bundey & Carter, 1974;Bundey et al, 1989;Costeff & Weller, 1987;Durkin et al, 1976;Herbst & Baird, 1982;Laxova, Ridler, Bowen-Bravery, & Opitz, 1977;Turner et al, 1971;Turner & Partington, 2000). Now, we provide estimates with narrow confidence intervals also for halfsiblings and other relatives.…”

Section: Main Findingssupporting

confidence: 86%

“…Second, severe ID is often associated with de novo mutations and low ID frequency in relatives (3%–5%; Angeli & Kirman, 1975, Bundey & Carter, 1974, Durkin et al., 1976), while mild ID may be a polygenic trait with higher risk (19%–26%; Bundey et al., 1989, Herbst & Baird, 1982).…”

Section: Introductionmentioning

confidence: 99%

“…The contribution of environmental and genetic factors has been traditionally measure by familial recurrence risk. We have systematically searched PubMed for articles published in English between 1 January 1970 and 30 September 2021 using the terms 'mental retardation' or 'ID' or 'mental deficiency' or 'retardation ' AND 'recurrence' or 'recurrence risk' or 'recurrent risk' or 'genetic studies' or 'familial' or 'twin' or 'sibling'. In general, studies of ID are scarce and mostly limited to old reports on ID frequency in siblings of ID individuals from one clinical center (Table S1; Angeli & Kirman, 1975;Becker, Kaveggia, Pendleton, & Opitz, 1977;Costeff & Weller, 1987;Durkin, Kaveggia, Pendleton, Neuhauser, & Opitz, 1976;Opitz, 1979;Opitz, Kaveggia, Durkin-Stamm, & Pendleton, 1978;Turner, Collins, & Turner, 1971). Twin studies of ID (Nichols, 1984;Wilson & Matheny, 1976) involve often too small samples (<10 monozygotic twin pairs) to draw reliable conclusions on the relative importance of genetic and environmental influences.…”

Section: Introductionmentioning

confidence: 99%

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Familial risk and heritability of intellectual disability: a population‐based cohort study in Sweden

Lichtenstein

Tideman

Sullivan

et al. 2021

Child Psychology Psychiatry

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Background Intellectual disability (ID) aggregates in families, but factors affecting individual risk and heritability estimates remain unknown. Methods A population‐based family cohort study of 4,165,785 individuals born 1973–2013 in Sweden, including 37,787 ID individuals and their relatives. The relative risks (RR) of ID with 95% confidence intervals (95% CI) were obtained from stratified Cox proportional‐hazards models. Relatives of ID individuals were compared to relatives of unaffected individuals. Structural equation modeling was used to estimate heritability. Results Relatives of ID individuals were at increased risk of ID compared to individuals with unaffected relatives. The RR of ID among relatives increased proportionally to the degree of genetic relatedness with ID probands; 256.70(95% CI 161.30–408.53) for monozygotic twins, 16.47(13.32–20.38) for parents, 14.88(12.19–18.16) for children, 7.04(4.67–10.61) for dizygotic twins, 8.38(7.97–8.83) for full siblings, 4.56(4.02–5.16) for maternal, 2.90(2.49–3.37) for paternal half‐siblings, 3.03(2.61–3.50) for nephews/nieces, 2.84(2.45–3.29) for uncles/aunts, and 2.04(1.91–2.20) for cousins. Lower RRs were observed for siblings of probands with chromosomal abnormalities (RR 5.53, 4.74–6.46) and more severe ID (mild RR 9.15, 8.55–9.78, moderate RR 8.13, 7.28–9.08, severe RR 6.80, 5.74–8.07, and profound RR 5.88, 4.52–7.65). Male sex of relative and maternal line of relationship with proband was related to higher risk (RR 1.33, 1.25–1.41 for brothers vs. sisters and RR 1.49, 1.34–1.68 for maternal vs. paternal half‐siblings). ID was substantially heritable with 0.95(95% CI 0.93–0.98) of the variance in liability attributed to genetic influences. Conclusions The risk estimates will benefit researchers, clinicians, families in understanding the risk of ID in the family and the whole population. The higher risk of ID related to male sex and maternal linage will be of value for planning and interpreting etiological studies in ID.

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Section: Main Findingssupporting

confidence: 92%

Section: Main Findingssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Familial risk and heritability of intellectual disability: a population‐based cohort study in Sweden

Lichtenstein

Tideman

Sullivan

et al. 2021

Child Psychology Psychiatry

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“…452 of the 706 children with SMR in this population (64%) (Rumeau-Rouquette et al 1994). Two other studies, one conducted in the UK and the other in the USA, examined children with SMR in hospital or institutions, and had similar results, with a high proportion of cases having an unknown aetiology (Angeli andKirman 1975, Opitz et al 1978). In a Swedish study of children born between 1959 and 1970, the results of the analysis were presented differently: 43% of children had a known aetiology, 43% had an identified perinatal risk factor, and 14% were without any aetiology or risk factor (Gustavson et al 1977).…”

mentioning

confidence: 91%

Aetiological findings and associated factors in children with severe mental retardation

Cans¹,

Wilhelm²,

Baille³

et al. 1999

Develop Med Child Neuro

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The purpose of this study, through a retrospective epidemiological survey carried out over three geographical areas in France, was to characterize the aetiological factors involved in severe mental retardation (SMR) within a geographically defined population of children with disabilities aged between 7 and 16 years. The inclusion criteria for SMR (IQ<50) were met by 1150 children born between 1976 and 1985. Of these children, aetiology was known in 25%, suspected (or unclear) in 26%, and unknown in 49%. These rates of known and suspected aetiology varied between the groups of children with CP and those without CP. An analysis of factors associated with SMR was undertaken among the 144 subjects with SMR, of suspected or unknown aetiology, who had been referred to a neonatal care unit with or without intensive care (NCU) during their neonatal period. These subjects with SMR were compared with 864 children without SMR (control children) who were also referred to an NCU during their neonatal period. The main specific associated factors were a prolonged intubation of more than 24 hours, a very low birthweight (<1500 g) for children with an associated clinical feature of CP, and the presence of isolated neonatal fits and a time of transfer to the NCU of more than 4 hours after birth for children without an associated clinical feature of CP. Although common associated factors were encountered in the children with SMR with CP and the children with SMR without CP, the results of this study suggest differences in the underlying pathogenic factors.

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A biologic and genetic study of 40 cases of severe pure mental retardation

et al. 1977

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The family history of 40 patients with severe "pure" mental retardation (MR) was studied to determine the incidence of mental retardation and dull-normal intelligence among relatives, probable etiologies and an empiric recurrence risk. Significant findings include: (1) an increased sex ratio (69% males) of propositi, (2) a significant proportion of patients with clinical manifestations besides MR, (3) virtually no consanguinity among parents, (4) a "positive" family history for over 1/2 of the propositi--about 37% of all children in the sibships were affected; about 21% of the full sibs were affected, (5) a higher number of offspring produced by dull persons and a lower number of offspring from retarded persons compared to two normal persons (6) a proportionately large number of affected children produced from matings involving one or two dull persons, (7) a tendency for dull to have additional dull children and mentally retarded parents to have further retarded children while normal parents with more than one affected child usually had further retarded children, (8) an incidence of affected parents of about 32%, and (9) an overall empiric recurrence risk of 14%. Several etiologies were discussed as possible causes of the condition(s) in this group: (unrecongized) environmental damage and/or maternal/fetal interaction; unrecognized chromosome abnormalities; the homozygous state of several different autosomal recessive gees: X-linked recessive mutations; autosomal dominat new mutations; and mutifactoral inheritance. It was concluded that the group was etiologically heterogeneous and although none of the probable etiologies could be excluded, it seemed reasonable to assume that autosomal recessive inheritance plays an important role in the etiology of severe "pure" mental retardation.

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Genetic Prognosis in Severe Mental Handicap

Cited by 9 publications

References 42 publications

Familial risk and heritability of intellectual disability: a population‐based cohort study in Sweden

Familial risk and heritability of intellectual disability: a population‐based cohort study in Sweden

Aetiological findings and associated factors in children with severe mental retardation

A biologic and genetic study of 40 cases of severe pure mental retardation

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