The epidemiology of preaxial limb malformations

Prevalence and risk factors of radial ray deficiencies: A population-based case-control study

Radial ray deficiency is the most common congenital deficiency of the upper limb. The aim of our study was to investigate maternal risk factors for radial ray deficiencies. We conducted a nationwide population-based case-control study using national registers. All cases with a radial ray deficiency born between 1996 and 2008 were included in the study and compared with five controls without limb deficiency. In total, 115 (10 isolated, 18 with multiple congenital anomalies, and 87 syndromic) cases with radial ray deficiencies were identified and compared with 575 matched controls. The total prevalence in Finland was 1.22 per 10,000 births. No significant risk factors were observed for nonsyndromic cases. In the syndromic group, advanced maternal age (≥35 years) increased the risk of radial aplasia (aOR 2.45, 95% CI 1.37-4.36), and a similar association was observed with multiple pregnancy (aOR 2.97, 1.16-7.62) and male sex (aOR 1.96, 1.18-3.25). Valproic acid was also a risk factor (p = .002). In conclusion, novel associations in the syndromic group of advanced maternal age and multiple pregnancy and increased risk of radial ray deficiencies were observed. Also, early reports on increased risk of RRD associated with valproate and male sex were supported by our results.

Heterogeneous Diagnoses Underlying Radial Ray Anomalies

OBJECTIVE

To review perinatal Radial Ray Anomaly (RRA) cases born at the National Institute of Perinatology, Mexico, and to reveal the heterogeneous diagnoses of these patients.

METHODS

All patients with RRA over a 18 mo period were included; 4/15 were detected prenatally and 11/15 postnatally. Karyotype was performed for all patients with bilateral RRA; and chromosomal breakage analysis, when the karyotype was normal.

RESULTS

Fifteen RRA patients were identified: one with trisomy 18, three with an isolated defect, six with monogenic disease, four with a genetic association and one with diabetic embryopathy. Five were stillborn and two died during the early neonatal period; all of whom presented with multiple defects. Three of the live born patients and one stillborn with multiple defects had Fanconi anemia. RRAs carry a high perinatal mortality rate (47%) when they occur in association with other defects.

CONCLUSIONS

The assessment of these patients needs to involve the combined use of ultrasound, clinical, genetic, cytogenetic and molecular testing. The present results indicate that the chromosome breakage test should always be performed to rule out Fanconi anemia in this group.

High risk for major nonlimb anomalies associated with lower-limb deficiency: a population-based study

BACKGROUND

The aims of this study were to determine the prevalence of congenital lower-limb reduction defects and associated mortality, to evaluate lower-limb deficiencies by type of reduction, and to identify patterns of associated anomalies.

METHODS

We conducted a population-based study with use of data from the Finnish Register of Congenital Malformations and Care Register for Health Care. All cases of lower-limb deficiency among live births, stillbirths, spontaneous abortions, and terminations of pregnancy due to fetal anomalies from 1993 to 2008 were included. We analyzed medical records and classified lower-limb reduction defects. Associated major anomalies were recorded, and perinatal mortality and infant mortality were calculated.

RESULTS

Two hundred and sixty-six cases with lower-limb deficiency were identified, with a total prevalence of 2.8 per 10,000 births, a birth prevalence of 2.2 per 10,000 births, and a live-birth prevalence of 2.1 per 10,000 live births. Terminal transverse limb reductions accounted for 44.7% of the cases; longitudinal reductions, 22.9%; intercalary reductions, 7.9%; multiple reductions, 8.3%; and split-foot malformations, 4.5%. In addition to lower-limb deficiency, 47.7% of the cases had other major anomalies; anomalies of internal organs were noted in 26.3% of the cases, anomalies of the axial skeleton in 13.5% of cases, and central nervous system anomalies in 12.8%. Upper-limb reductions were observed in 32.0% of the cases. The relative risk (RR) for associated major anomalies was 12.54 (95% confidence interval [CI], 11.06 to 14.23) compared with the general figures for major congenital anomalies in Finland. The RR for associated anomalies was higher (1.75; 95% CI, 1.20 to 2.53) for longitudinal preaxial lower-limb deficiencies than for the other types of lower-limb reductions. Perinatal mortality was seventy-eight per 1000 births. All infant deaths were associated with chromosomal abnormalities, other known syndromes, or additional congenital malformations.

CONCLUSIONS

Nearly half of the cases with lower-limb deficiencies were found to have other major anomalies. In cases of preaxial lower-limb deficiencies, the risk for associated major anomalies was highest.

Characteristics and associated anomalies in radial ray deficiencies in Finland--a population-based study

Upper-limb defects with deficiencies of the radial ray have varying etiologies, with a low proportion of true Mendelian disorders. We carried out a population-based study to elucidate the birth prevalence and clinical spectrum of radial ray deficiencies in Finland. We identified all births with radial ray deficiency reported to the Finnish Register of Congenital Malformations in 1993-2005. Altogether 138 cases were identified (123 live births), with a birth prevalence of 1.83 per 10,000 births and a live birth prevalence of 1.64 per 10,000 live births. The proportion of infant deaths was as high as 35%. The majority of the cases were associated with known syndromes or multiple anomalies; only 13% were true isolated radial ray deficiencies. The most common syndrome was trisomy 18, and the most common in multiple anomalies was VACTERL association. In 8.7% of cases an association between radial ray deficiency and heart anomaly was observed. The high proportion of cases with associated major anomalies indicates that radial ray deficiency can be regarded isolated only after thorough assessment of the various organ systems in an affected infant.

Associated malformations in patients with limb reduction deficiencies

Infants with limb reduction deficiencies (LRD) often have other associated congenital malformations. The purpose of this investigation was to assess the prevalence and the types of associated malformations in a defined population. This study included special strengths: each affected child was examined by a geneticist, all elective terminations were ascertained, and the surveillance for malformations was continued until 1 year of age. The associated malformations in infants with LRD were collected in all livebirths, stillbirths and terminations of pregnancy during 25 years in 347,810 consecutive births in the area covered by our population based registry of congenital malformations. Of the 271 LRD infants born during this period, representing a prevalence of 7.8 per 10,000, 57.9% had associated malformations. There were 17(6.3%) patients with chromosomal abnormalities including 10 trisomies 18, and 62 (22.9%) nonchromosomal recognized dysmorphic conditions. There were no predominant recognized dysmorphic conditions, but VA(C)TER(L) association. However numerous recognized dysmorphic conditions were registered including Poland, ectrodactyly-ectodermal dysplasia-clefting, oral-facial-digital, Klippel-Trenaunay-Weber, oculo-auriculo-vertebral defect spectrum, CHARGE, Townes-Brocks, Moebius, Du Pan, Smith-Lemli-Opitz, hypoglossia-hypodactyly, amniotic band, De Lange, Rubinstein-Taybi, Fanconi, radius aplasia- thrombocytopenia, Roberts, Holt-Oram, and fetal diethylstilbestrol. Seventy eight (28.8%) of the patients were multiply, non-syndromic, non chromosomal malformed infants (MCA). Malformations in the cardiac system, in the genital system, and in the central nervous system were the most common other malformations, 11.4%, 9.4%, and 7.7% of the associated malformations, respectively, followed by malformations in the renal system (4.8%), and in the digestive system (4.6%). Prenatal diagnosis was performed in 48.4% of dysmorphic syndromes with LRD. The overall prevalence of associated malformations, which was more than one in two infants, emphasizes the need for a thorough investigation of infants with LRD.A routine screening for other malformations especially cardiovascular system, urogenital system, central nervous system, and digestive system may be considered in infants and in fetuses with LRD.

Maternal nickel exposure and congenital musculoskeletal defects

OBJECTIVE

To investigate whether women occupationally exposed to nickel in early pregnancy are at elevated risk of delivering a newborn with a malformation or deformation of the musculoskeletal system (ICD-10: Q65-Q79).

METHODS

Data about the newborn, maternal occupation and workplace were obtained using the Kola Birth Register (KBR). Each record in the KBR was assigned a categorical nickel (Ni) exposure rating according to the occupation the delivering woman had at the time of becoming pregnant. This was achieved by using as a guideline the water-soluble Ni subfraction of the inhalable aerosol fraction obtained by personal monitoring for nickel- and copper-refinery workers or/and measured urinary-Ni concentrations. The reference population was delivering women from the source population with background exposure level. In total, the study population consisted of 22,965 births.

RESULTS

Three hundred and four infants (13.3/1,000 births; 95% confidence interval (CI): 11.9-14.7) were diagnosed with isolated musculoskeletal defect(s) at birth. The adjusted odds ratio for the association between the maternal exposure to Ni and this outcome was 0.96 (95% CI: 0.76-1.21) per unit increase in exposure category.

CONCLUSION

The incidence of defects in the musculoskeletal system at birth was high, especially for feet deformities, but we found no effect of maternal exposure to water-soluble Ni on the risk of delivering a newborn with a defect. However, the incidence among women working in the copper refinery was higher than in the other employment groups.

Congenital malformations: an inquiry into classification and nomenclature

In the beginning, as a familiar book recalls, the earth was a formless void. And by separating light from dark, water from sky, life from dust, order came forth. Thus appeared organisation and categorisation. This is to say, classification, since to classify is to make for order and clarity. These are the qualities needed today for the study of congenital malformations and eventual control of their occurrence. What follows is an inquiry into the present state of this desideratum.