Anencephaly and limb deficiencies

Congenital limb deficiencies and major associated anomalies in Alberta for the years 1980-2012

There is a wide range of the proportion of congenital anomalies associated with limb deficiencies reported in the literature. This variation is primarily attributed to methodology and classification differences. The distribution of associated anomalies among cases with congenital limb deficiencies in Alberta born between January 1, 1980 and December 31, 2012 is described. Of the 170 cases identified, most were live born (75.3%), male (61.8%), had longitudinal limb deficiencies (78.8%), and had associated anomalies outside the musculoskeletal system (77.6%). Significant associations between the preaxial longitudinal group and the central nervous, gastrointestinal, and cardiovascular systems are reported as well as between the postaxial longitudinal group and congenital hip and foot anomalies. Probable and possible syndrome diagnoses are described for cases with recognized malformation patterns.

Diaphragmatic defects and limb deficiencies - taking sides

Diaphragmatic defects and limb deficiencies usually occur as independent anomalies, as a polytopic field defect (in which ipsilateral anomalies might be expected) or as wider pattern of defects, potentially involving disturbance of laterality or the midline (in which bilateral or contralateral defects would occur). Data on cases from previous studies and/or the literature were used to determine whether there is an association between the sides involved in the defects. The 88 adequately described cases identified included 20 with de Lange syndrome, seven with Poland anomaly, four with trisomy 18, 52 with other patterns of multiple malformations and five with diaphragmatic and limb defects alone. Evaluation of the position of the limb (left, right, bilateral) and the diaphragmatic defects (left, right, bilateral) did not show significant association in patterns of sidedness (P = 0.48). In 56% of cases, the limb deficiencies were bilateral. Among the 32 unilateral cases, 19 (59%) were ipsilateral (15 left; 4 right) and 13(41%) were contralateral (P = 0.38). Eleven of the 13 contralateral cases had left sided diaphragmatic defects and right sided limb deficiency; four had de Lange syndrome and nine had other patterns of multiple anomalies. Only cases with Poland anomaly or otherwise isolated defects showed a trend towards ipsilateral defects. Most cases with multiple congenital anomalies, had limbs defects on both the right and left (57%) or both sides of the diaphragm were affected (an additional 10%), indicating a widespread dysmorphogenetic process rather than a more restricted field defect. In other cases, defects were bilateral or, if unilateral, reflected the propensities for diaphragmatic defects to more often involve the left side, and limb defects, the right.

Embryology of neural tube defects: information provided by associated malformations

OBJECTIVES

To get information about embryologic mechanisms of neural tube defects (NTD), by studying the associated malformations.

METHODS

Eighty three cases of NTD, seen at the prenatal diagnosis unit of Rennes University Hospital (France) between May 1999 and December 2002, were retrospectively studied. Cases with chromosomal anomalies (5/83), cases without available karyotype or pathologic examination were excluded. 24 spina bifida, and 27 cephalic forms (anencephalies, exencephalies, and encephaloceles) were thus analyzed.

RESULTS

Only 22/51 cases (43%) were strictly isolated NTD. Anomalies of tissues arising from neural crests were noted in 8/51 fetuses (16%), midline or lateralization anomalies in 12/51 (24%), and anomalies of mesoblastic tissues in 17/51 (33%). An already known syndrome was found in 4/51 cases (8%).

CONCLUSION

NDT are more extensive congenital damages that would suggest the restrictive terminology. That prompts to assess cautiously prenatal diagnosis of NTD, and to get detailed pathological examination after termination of pregnancy.

Neural tube defects in the sample of genetic counselling

OBJECTIVE

This study was conducted to evaluate the major demographic details, diagnostical and clinical features, as well as the risk of recurrence of cases with the major types of neural tube defects (NTD). We also examined the efficiency of ultrasonography based on autopsy examinations during 26 years.

METHODS

The investigations were made into the sample of 743 NTD diagnosed between 1 January 1976 and 31 December 2002. A computerized database was used to sum up the available information about the individual cases; in addition to surveying the couples' major demographic details, we also had the opportunity to collect detailed information about the history, diagnostics (ultrasound) and outcome of the pregnancies as well as the results of the autopsies during the investigation.

RESULTS

In the 743 cases of NTD, maternal and paternal median ages turned out to be 23.7 years (+/-5.22 years) and 28.7 years (+/-5.81 years), respectively. The male:female ratio was 0.78. Comparable samples of anencephaly and spina bifida allowed for the conclusion that a positive genetic history was equally often found while a positive obstetrical history was almost twice as common in anencephaly. The sensitivity of the maternal serum-alpha fetoprotein (AFP) screening test is the highest in anencephaly and lowest in encephalocele. While the majority of cases of anencephaly were diagnosed before the 24th gestational week, examples of diagnosing spina bifida and encephalocele at a later time could also be found. Among the associated malformations other than those of the central nervous system special mentioning should be made of fetal pyelectasia, cleft palate as well as diaphragmatic herniation. No pathological karyotypes were found in association with encephalocele or spina bifida, but anencephaly was accompanied with trisomy 21 and trisomy 18 in one case each. Anencephaly was found to have the highest risk of recurrence in both nervous system malformations and malformations other than those of the nervous system. Sonography proved to be the most reliable method in cases of enecephalocele.

CONCLUSION

The respective median values of maternal and paternal age show that aetas has no role in the occurrence of NTDs. NTDs are more common among girls. Positive genetic, obstetrical and medical findings are of great importance in the incidence of NTDs. Although reliable to only a limited extent, maternal serum-AFP tests are considered to be useful and necessary in screening NTDs, while sonography is the gold standard method in recognizing these frequent malformations. The knowledge of the eventual associated malformations is mainly important in certain cases of spina bifida, which may also yield a good post-natal prognosis. Our data obtained from the sample of 26 years also confirm that the periconceptional administration of folic acid reduces the incidence and risk of recurrence of NTDs.

XK-aprosencephaly and related entities

We offer further biological characterization of the XK atelen/aprosencephaly syndrome in two infants, one with prolonged survival, the other presenting prenatally with apparent hydranencephaly and an orbital tumor (OS). Familial occurrence in the former born to presumably nonconsanguineous Lybian parents may represent parental germinal mosaicism or autosomal recessive inheritance. Both had apparently normal chromosomes; however, the Lybian infant had slightly increased induced chromosome breakage suggesting that this rare multiple congenital anomalies syndrome may involve a DNA repair defect. Virtual absence of atelen/aprosencephalic structures may lead to an arthrogryposis-like prenatal movement disorder. The orbital tumor in the Utah infant consisted of dystopic neural tissue compressing a rudimentary globe and was connected by a thin bridge of neural tissue to the small mass of disorganized brain tissue usually found in atelen/aprosencephalic infants and fetuses. No evidence of an encephaloclastic process was found in the autopsied Utah infant.

Anomalous costochondral cartilage in fetal anencephaly

Anencephaly is a human fetal malformation with absence of brain and calvarium superior to the orbits. The consequent absence of hypothalamus provides a unique model for studying human development, and therefore skeletal growth, in the absence of hypothalamic hormones and their regulatory functions. To assess the influence of hypothalamic insufficiency on cartilage development, we studied costochondral cartilage sections from eight anencephalic fetuses (18-22 weeks old) and seven controls (16-22 weeks old) with pathologies not directly related to skeletal growth. We found a previously undescribed anomalous organization of the cartilage in the anencephalic. The proliferative chondrocytes showed a disordered appearance with an increased proliferative zonal length (156 +/- 28 microm in anencephalic fetuses vs. 103 +/- 14 microm in controls, p = 0.006) and a concomitant decrease in the maturing portion, where cells form ordered isogenic groups (58 +/- 13 microm in anencephalic fetuses vs. 93 +/- 19 microm in controls, p = 0.003). In addition, cell density was significantly decreased in the proliferating and maturing zones in the anencephalic cases (84 +/- 21 vs. 130 +/- 21 cells/40 microm(2) in proliferating zone; 53 +/- 8 vs. 94 +/- 8 in maturing portion, p < 0.005). These alterations in the developing cartilage of the anencephalic may contribute to the observed growth retardation in these fetuses and reflect modifications in pituitary hormones and growth factors resulting from reduction in hypothalamopituitary function.

Radioulnar synostosis, radial ray abnormalities, and severe malformations in the male: a new X-linked dominant multiple congenital anomalies syndrome?

We describe a multiple congenital anomalies (MCA) syndrome dominantly transmitted through three generations. Radial ray abnormalities with wide variability of expression were observed in four female patients. Moreover, a 14-week-gestation male fetus had severe radial ray malformation, anencephaly, unilateral renal agenesis, and a common dorsal mesentery. Results of high-resolution karyotyping were normal in the malformed fetus and his affected mother. Furthermore, several spontaneous abortions of male fetuses had occurred in this pedigree. To our knowledge, a similar association has not been described previously. It could represent a new X-linked dominant MCA syndrome, or an autosomal dominant condition with severe expression limited to males.

Classifying sex biased congenital anomalies

The reasons for sex biases in congenital anomalies that arise before structural or hormonal dimorphisms are established has long been unclear. A review of such disorders shows that patterning and tissue anomalies are female biased, and structural findings are more common in males. This suggests different gender dependent susceptibilities to developmental disturbances, with female vulnerabilities focused on early blastogenesis/determination, while males are more likely to involve later organogenesis/morphogenesis. A dual origin for some anomalies explains paradoxical reductions of sex biases with greater severity (i.e., multiple rather than single malformations), presumably as more severe events increase the involvement of an otherwise minor process with opposite biases to those of the primary mechanism. The cause for these sex differences is unknown, but early dimorphisms, such as differences in growth or presence of H-Y antigen, may be responsible. This model provides a useful rationale for understanding and classifying sex-biased congenital anomalies.

DK-phocomelia syndrome in a child with a long follow-up

We report on an 8-year-old boy with a pattern of multiple congenital anomalies that strongly suggest DK-phocomelia syndrome. Birth findings included bilateral upper limb amelia, occipital encephalocele, agenesis of the corpus callosum, right auricular tag, scoliosis, small penis, and cryptorchidism. Dental malocclusion was observed in the follow-up. This is the first case with on 8-year follow-up report of DK-phocomelia syndrome.

Congenital abnormalities associated with limb deficiency defects: a population study based on cases from the Hungarian Congenital Malformation Registry (1975-1984)

Limb deficiency defects (LD) occurring among 1,575,904 births in Hungary during 1975-1984 were reviewed. The overall birth prevalence of LD was 1 in 1,816. This paper discusses the nature and distribution of the limb and other defects in the 275 (32%) children who had structural malformations in other systems. Two main forms of classification were used: morphologic and causal. Additional malformations were most commonly seen in infants with amelia, rudimentary limb (RL), radial/tibial (RT), intercalary or central axis (CA) LD and rarely in those with terminal transverse (TT) or ulnar/fibular (UF) defects. Upper limbs (81%) were involved significantly more often than lower limbs (42%) and there were more right-sided defects (83% vs. 71%) due to an excess of right arm involvement especially with radial ray and split hand anomalies. Single limb involvement was relatively common with amelia (88%), UF (82%), RT (50%), and TT (50%) defects. With other LD, multimelic involvement was more characteristic. This was usually symmetric with intercalary and RL defects but asymmetric with CA anomalies and digital deficiencies (DD). From a causal perspective, 17% of cases had genetic disorders, 52% had recognized associations, anomalies, sequences, environmental causes or patterns of unknown origin, and 31% had unknown patterns of malformations. The commonest entities were amnion disruption sequence (16% of cases) and VACTERL association (8%). Both of these disorders showed unusual temporal distribution. As anticipated, patterns of malformations differed with the type of LD. Amelia and digital amputations were often seen with body wall defects, atypical anencephaly or encephalocele, and cleft lip reflecting amnion disruption. Rudimentary limb was seen with anencephaly, omphalocele, renal agenesis, aberrant genitalia, and imperforate anus, reflecting defects of blastogenesis including the cloacal exstrophy and caudal regression sequences and Schisis association. Radial/tibial defects were associated with different patterns depending on whether the limb defects were unilateral or bilateral. Unilateral defects occurred with anomalies suggesting VACTERL association or the facio-auriculo-vertebral anomaly, while bilateral defects occurred more often in genetic or potentially genetic disorders including VACTERL with hydrocephalus. Central axis defects showed three main patterns of association: one reflecting the ectrodactyly-ectodermal dysplasia-clefting syndrome; one with tongue anomalies representing a variant of oro-mandibular-limb (Hanhart) anomaly, and the last with hydronephrosis indicating a group of "acro-renal" syndromes. Strong associations with other anomalies were not seen in the groups with TT, UF, or intercalary defects.