Cancer and congenital abnormalities in Asian children: a population-based study from the West Midlands

Risk of thyroid neoplasms in patients with 22q11.2 deletion and DiGeorge-like syndromes: an insight for follow-up

Introduction

The chromosome 22q11.2 deletion syndrome comprises phenotypically similar diseases characterized by abnormal development of the third and fourth branchial arches, resulting in variable combinations of congenital heart defects, dysmorphisms, hypocalcemia, palatal dysfunction, developmental or neuropsychiatric disorders, and impairment of the immune system due to thymic dysfunction. Other genetic syndromes, often called DiGeorge-like, share clinical and immunological features with 22q11.2 deletion syndrome. This syndrome has been rarely associated with malignancies, mainly hematological but also hepatic, renal, and cerebral. Rarely, malignancies in the head and neck region have been described, although no aggregate of data on the development of thyroid neoplasms in patients with this clinical phenotype has been conducted so far.

Materials and methods

To characterize this possible association, a multicenter survey was made. Thus, we present a case series of five pediatric patients with 22q11.2 deletion syndrome or DiGeorge-like syndrome who were occasionally found with confirmed or highly suspected neoplasms of the thyroid gland during their follow-up. In three cases, malignancies were histologically confirmed, but their outcome was good due to an early recognition of suspicious nodules and precocious surgery.

Conclusions

This study underlines for clinicians the higher risk of neoplasms in the head and neck district for patients affected by these syndromes. It also emphasizes the importance of a prolonged clinical and ultrasound follow-up for patients with this clinical and immunological phenotype.

Consanguinity and childhood acute lymphoblastic leukaemia: a case-control study

Background

Consanguineous marriage is widely practised across the world. Its effect on acute lymphoblastic leukaemia (ALL) is controversial as both parents share some of the genes which might increase the incidence of sharing recessive genes. However, other theories suggest that consanguinity might have a protective factor as it does for other types of cancers. This study aims to study childhood ALL and consanguinity.

Methods

This is a case-control study, conducted in the major paediatric hospital in Damascus, Syria, using medical records. Case group included children with ALL, while control group included other patients and were matched by gender and age.

Results

This study comprised 386 patients, 193 of which were cases. Overall, 136 were of consanguineous marriages (36.8%), and there was no difference in consanguinity overall between cases and controls. However, when only comparing non-consanguineous parents and fourth-degree consanguinity, fourth degree was significantly higher among case group, suggesting a negative correlation OR = 0.387 (0.187–0.801) in contrast to third-degree consanguinity which was no significantly different when comparing the two groups (p > 0.05). We found no significant association between ALL and having a family history of cancer (p > 0.05) or between parents’ educational level and case-control groups (p > 0.05).

Conclusion

Our research suggests a negative association between fourth-degree consanguinity and childhood leukaemia. This was not observed with a third-degree consanguinity. Previous studies had contradicting data on consanguinity and ALL which demonstrates the need for further research.

Risk of cancer among children with birth defects: a novel approach

BACKGROUND

Associations between birth defects (BDs) and childhood cancers have been studied previously and have identified several specific birth defect-cancer associations. No studies have examined the risk after exclusion of known associations.

METHODS

We analyzed data from high-quality population-based registers of BDs and cancers for Western Australian births 1982 to 2007. The cohort comprised 641,036 babies still alive at 90 days. Two experts independently reviewed all 120 births with a BD and a cancer to determine whether the cancer was congenital, caused by the BD, known to be associated with the BD or otherwise. These categories were used in sensitivity analyses. Cox regression was used to estimate hazard ratios (HRs) for any cancer and specific cancers associated with any BD and specific BDs.

RESULTS

The HR for any cancer among children with any BD was 1.96 (95% confidence interval, 1.59-2.43). The HR for any cancer among children with a BD not known to be related to a cancer (n = 57) was 1.19 (95% confidence interval, 0.91-1.56). The HR for the latter association among children diagnosed with cancer before 5 years of age was 1.74 (95% confidence interval, 1.28-2.37).

CONCLUSION

This novel approach aimed to prevent inflated HRs arising from reverse causation, and allow identification of associations beyond those already well documented. Larger studies using this method are needed to explore currently undocumented associations between BDs and cancers.

[Minor phenotypic variants in patients with acute lymphoblastic leukemia from west Mexico]

INTRODUCTION

Acute lymphoblastic leukemia (ALL) has been associated with an excess of minor phenotypic variants (MPV), including common variants and minor anomalies, indicative of an altered phenogenesis. The objective of the study was to determine the association between MPV and ALL.

PATIENTS AND METHODS

In a hospital based case-control study, we studied 120 children with ALL (including standard and high risk) and 120 healthy children as a control group, matched for age and sex, seen in the Hospital Civil de Guadalajara Dr. Juan I. Menchaca (Guadalajara, Mexico). In both groups, 28 anthropometric measurements were made, as well as a systematic search for 405 MPV, through a physical examination. Adjusted odds ratio was estimated (aOR) with its intervening variables by logistic regression. The confidence interval was 95% (95%CI).

RESULTS

Anthropometric signs associated with ALL were: long upper segment (aOR= 2.19, 95%CI: 1.01-4.76), broad jaw (aOR= 2.62, 95%CI: 1.29-5.30), narrow ears (aOR= 6.22, 95%CI: 2.60-14.85), and increase in internipple distance (aOR= 2.53, 95%CI: 1.07-5.98). The hypoplasia mesofacial, broad forehead, small nose, short columella, narrow ears, telethelia, Sydney crease (SC), Greek type feet and café-au-lait spots (CALS), had a 3 to 17 times higher frequency in children with ALL. By number, an association was found from ≥4 MPV (aOR= 2.14, 95%CI: 1.25-3.66, P=.004).

CONCLUSIONS

From ≥4 MPV, an association was found with ALL, suggesting prenatal factors in phenogenesis and leukemogenesis. CALS and SC were confirmed as MPV in children with ALL.

Cancer risk in children and adolescents with birth defects: a population-based cohort study

Objective

Birth defects are an increasing health priority worldwide, and the subject of a major 2010 World Health Assembly Resolution. Excess cancer risk may be an added burden in this vulnerable group of children, but studies to date have provided inconsistent findings. This study assessed the risk for cancer in children and young adolescents with major birth defects.

Methods and Findings

This retrospective, statewide, population-based, cohort study was conducted in three US states (Utah, Arizona, Iowa). A cohort of 44,151 children and young adolescents (0 through 14 years of age) with selected major, non-chromosomal birth defects or chromosomal anomalies was compared to a reference cohort of 147,940 children without birth defects randomly sampled from each state’s births and frequency matched by year of birth. The primary outcome was rate of cancer prior to age 15 years, by type of cancer and type of birth defect. The incidence of cancer was increased 2.9-fold (95% CI, 2.3 to 3.7) in children with birth defects (123 cases of cancer) compared to the reference cohort; the incidence rates were 33.8 and 11.7 per 100,000 person-years, respectively. However, the excess risk varied markedly by type of birth defect. Increased risks were seen in children with microcephaly, cleft palate, and selected eye, cardiac, and renal defects. Cancer risk was not increased with many common birth defects, including hypospadias, cleft lip with or without cleft palate, or hydrocephalus.

Conclusion

Children with some structural, non-chromosomal birth defects, but not others, have a moderately increased risk for childhood cancer. Information on such selective risk can promote more effective clinical evaluation, counseling, and research.

The prevalence of patients with ocular genetic disorders attending a general paediatric ophthalmology clinic in the East End of London

AIMS

To document the prevalence of ocular genetic disorders in a general paediatric ophthalmology clinic in a deprived, ethnically diverse inner city area of London, and to assess the consanguineous relationships and ethnicity among families with these conditions.

METHODS

A prospective audit documented all ocular genetic conditions (excluding strabismus and amblyopia) presenting for 16 consecutive weeks to the paediatric ophthalmology clinic. Information regarding ethnicity and consanguinity were sought. The disorders were divided according to the mode of inheritance if known.

RESULTS

Thirteen per cent of patients (45/342) had an ocular genetic disorder or were being examined for one. Of them, 22% (10/45) had a history of consanguinity with an inheritance pattern of 30% autosomal recessive (3/10), 20% autosomal dominant, 50% X-linked/unknown/isolated cases. In the remaining non-consanguineous families (35/45), 22% were autosomal recessive, 17% autosomal dominant, and 60% X-linked/unknown/isolated cases. The vast majority of cases (9/10) with a history of consanguineous marriage had South Asian ancestry. Variable ethnic backgrounds were documented for patients with genetic disease and no consanguinity.

CONCLUSION

Ocular genetic disorders are common in secondary care. Less than a third of patients with such disorders had a family history of consanguinity. The proportion of patients with proven autosomal recessive disease was similar irrespective of consanguinity within family. The proportion of children of South Asian ancestry was high in this clinic population.

Congenital abnormalities and clinical features associated with Wilms’ tumour: A comprehensive study from a centre serving a large population

Altogether 156 children treated for Wilms' tumour (WT) between 1970 and 1998 were studied. Sixty-six children, selected only by their attendance at clinic, were carefully examined and the findings compared to those from a case note review of 90 children. Congenital abnormalities were present in 45% of the examined cohort, in 19% of the case notes review group and in 30% overall. Novel findings included the association of WT with Marshall Smith syndrome, developmental delay in 3 of 4 cases of WT (one bilateral) and 1 sibling from consanguineous Pakistani families and another sibling also had leukaemia. The possibility of rare DNA repair or cancer predisposing disorders among these 4 families requires further study. Careful examination and history taking of an unselected patient cohort revealed a higher than expected incidence of clinical abnormalities which may be overlooked if not specifically sought.

Epidemiology and genetics of childhood cancer

Childhood cancer is rare everywhere in the world, with age-standardized annual incidence usually between 70 and 160 per million at age 0-14 years. Greater variation is seen between populations for some specific tumour types. Some of the largest variations are geographical and are attributable to environmental factors, whereas variation mainly on ethnic lines seems likely to be a marker of genetic predisposition. A wide range of familial and genetic syndromes is associated with an increased risk of childhood cancer. Virtually all the excess risk of cancer among first-degree relatives of children with cancer can be accounted for by known hereditary syndromes. Studies of weak predisposition and gene-environment interaction have so far shown limited consistency. There are very few established environmental or exogenous risk factors and most of these are infective agents. Many putative risk factors can hardly ever be investigated epidemiologically except by interview or questionnaire studies. Some recent examples illustrate the continuing problems of participation bias and recall bias.

Contribution of BRCA1 and BRCA2 mutations to breast and ovarian cancer in Pakistan

The population of Pakistan has been reported to have the highest rate of breast cancer of any Asian population (excluding Jews in Israel) and one of the highest rates of ovarian cancer worldwide. To explore the contribution that genetic factors make to these high rates, we have conducted a case-control study of 341 case subjects with breast cancer, 120 case subjects with ovarian cancer, and 200 female control subjects from two major cities of Pakistan (Karachi and Lahore). The prevalence of BRCA1 or BRCA2 mutations among case subjects with breast cancer was 6.7% (95% confidence interval [CI] 4.1%-9.4%), and that among case subjects with ovarian cancer was 15.8% (95% CI 9.2%-22.4%). Mutations of the BRCA1 gene accounted for 84% of the mutations among case subjects with ovarian cancer and 65% of mutations among case subjects with breast cancer. The majority of detected mutations are unique to Pakistan. Five BRCA1 mutations (2080insA, 3889delAG, 4184del4, 4284delAG, and IVS14-1A-->G) and one BRCA2 mutation (3337C-->T) were found in multiple case subjects and represent candidate founder mutations. The penetrance of deleterious mutations in BRCA1 and BRCA2 is comparable to that of Western populations. The cumulative risk of cancer to age 85 years in female first-degree relatives of BRCA1-mutation-positive case subjects was 48% and was 37% for first-degree relatives of the BRCA2-mutation-positive case subjects. A higher proportion of case subjects with breast cancer than of control subjects were the progeny of first-cousin marriages (odds ratio [OR] 2.1; 95% CI 1.4-3.3; P=.001). The effects of consanguinity were significant for case subjects with early-onset breast cancer (age <40 years) (OR=2.7; 95% CI 1.5-4.9; P=.0008) and case subjects with ovarian cancer (OR=2.4; 95% CI 1.4-4.2; P=.002). These results suggest that recessively inherited genes may contribute to breast and ovarian cancer risk in Pakistan.

Lay perceptions of genetic risks attributable to inbreeding in Pakistan

Pakistan along with many other West and South Asian countries has a very high prevalence of consanguineous, especially close cousin, marriages. Although there is substantial empirical information on offspring morbidity and mortality attributable to parental consanguinity, population-based information on how communities in general, and women in particular, perceive the health risks associated with consanguineous unions is limited. This paper considers community perceptions of health effects associated with consanguineous marriages using qualitative data from 15 focus group discussions and 294 in-depth interviews. The study was conducted in four low-income, multi-ethnic, and multi-religious communities in Karachi, the principal commercial center of Pakistan. The results show a general lack of awareness of the possible adverse health effects of consanguineous marriage. In cases where a link between consanguinity and ill health was acknowledged, it often centered on the familial origins of non-communicable disorders such as diabetes and hypertension or infectious diseases such as tuberculosis. Belief in fate and the "evil eye" was widespread across all ethnic and religious groups. Many respondents did not agree with medical explanations of a genetic mode of disease inheritance, even in cases where there was an affected child in the family. The absence of a uniform manifestation of disease among all children of a couple who were identified as carriers of a specific mutation added to the confusion among participants. The study highlights the need for further quantification of risks associated with consanguinity and a need for provision of appropriate information to primary-care clinicians and also to communities. The likely impact of increasing morbidity attributable to inbreeding on the health care system in resource poor settings is also discussed.

Consanguinity and family history of cancer in children with leukemia and lymphomas

BACKGROUND

In native population of the United Arab Emirates (UAE), the rate of consanguineous marriages is 50.5%. This study was designed to determine whether the rates of consanguinity and family history of cancer among the families of children with lymphoid malignancy are different from those in the general population.

METHODS

The study comprised 117 patients from the whole of the country with acute lymphocytic leukemia (ALL) and Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL), ranging in age from 2 to 14 years. The consanguinity rate in the study group was compared with the rate in the general population. To study family history of cancer, the authors matched patients with 117 controls. In a telephone interview, each mother was asked to provide data regarding the biologic relationship between her and her husband as well as that between both sets of grandparents; each was also asked whether any family relative had a cancer and, if so, of what type.

RESULTS

Among the 69 ALL cases, 80% of families were consanguineous and 20% were nonconsanguineous. Among the 26 NHL and 22 HL cases, each group included 3 consanguineous families, 12% and 14%, respectively. The consanguinity rates for ALL, NHL, and HL were all significantly different from the 50.5% consanguinity rate in the UAE population (all three P values < 0.0001). The family history of cancer was more often positive in ALL patients than in controls (odds ratio, 2.14; confidence interval, 1.01--4.53). Overall and for each lymphoid malignancy, there was no difference in family history of cancer between consanguineous and nonconsanguineous groups of cases.

CONCLUSIONS

The consanguinity rate in the families of patients with ALL is significantly higher and in those with NHL and HL significantly lower than that in the UAE population. The family history of cancer is more often positive among ALL cases than controls--consanguinity having no effect.