Pathological features and prenatal diagnosis in the newly recognised limb/pelvis-hypoplasia/aplasia syndrome

Roles of Wnt7a in embryo development, tissue homeostasis, and human diseases

Human Wnt family comprises 19 proteins which are critical to embryo development and tissue homeostasis. Binding to different frizzled (FZD) receptor, Wnt7a initiates both β-catenin dependent pathway, and β-catenin independent pathways such as PI3K/Akt, RAC/JNK, and extracellular signal-regulated kinase 5/peroxisome proliferator-activated receptor-γ. In the embryo, Wnt7a plays a crucial role in cerebral cortex development, synapse formation, and central nervous system vasculature formation and maintenance. Wnt7a is also involved in the development of limb and female reproductive system. Wnt7a mutation leads to human limb malformations and animal female reproductive system defects. Wnt7a is implicated in homeostasis maintenance of skeletal muscle, cartilage, cornea and hair follicle, and Wnt7a treatment may be potentially applied in skeletal muscle dystrophy, corneal damage, wound repair, and hair follicle regeneration. Wnt7a plays dual roles in human tumors. Wnt7a is downregulated in lung cancers, functioning as a tumor suppressor, however, it is upregulated in several other malignancies such as ovarian cancer, breast cancer, and glioma, acting as a tumor promoter. Moreover, Wnt7a overexpression is associated with inflammation and fibrosis, but its roles need to be further investigated.

Molecular basis of the clinical features of Al-Awadi-Raas-Rothschild (limb/pelvis/uterus-hypoplasia/aplasia) syndrome (AARRS) and Fuhrmann syndrome

This paper reviews the molecular basis of the clinical features of Al-Awadi-Raas-Rothschild (limb/pelvis/uterus-hypoplasia-aplasia) (AARRS) syndrome and Fuhrmann syndrome. Human WNT7A mutations are also reviewed. Based on this review, these mutations will be classified into two main groups of phenotypes: Fuhrmann and AARRS phenotypes in which there is partial and complete loss of WNT7A functions, respectively.

Limb/pelvis-hypoplasia/aplasia syndrome--further delineation of phenotype

We report a case of Al-Awadi/Raas-Rothschild syndrome, an autosomal recessive disorder manifesting at an early gestation as hydrops as a result of congenital high airway obstruction.

Al-Awadi/Raas-Rothschild syndrome in a newborn with additional anomalies

Al-Awadi/Raas-Rothschild (AARR) syndrome is a rare phocomelia syndrome characterized by limb/pelvic hypoplasia/aplasia, renal anomalies such as horseshoe and polycystic kidney, and abnormal facial features including cleft palate, hypertelorism and micro-retrognatia. Autosomal recessive inheritance has been proposed for AARR syndrome. In this report a boy affected with AARR syndrome is presented. The previous pregnancy of the mother was terminated because of lower limb agenesis detected at 14th week of gestation. This report emphasizes the importance of recognizing severe pelvic and limb deficiencies in newborns with AARR syndrome and differentiating the syndrome from other multiple malformation syndromes. Fetal ultrasonography at 15th week of gestation is helpful in diagnosing the major extremity anomalies in the fetus.

Al-Awadi/Raas-Rothschild syndrome: two new cases and review

Al-Awadi/Raas-Rothschild syndrome, an autosomal recessive disorder, is characterized by severe malformations of the upper and lower limbs, and a hypoplastic pelvis. We describe two new cases with the typical manifestations, report some new findings, review the relevant literature, and present minimal criteria for the diagnosis. A single homozygous WNT7A mutation was identified by Woods et al. [2006]: 1179C --> T, resulting in Arg292Cys with complete loss of WNT7A function.

A newly recognized syndrome involving limbs, pelvis, and genital organs or a variant of Al-Awadi/Raas-Rothschild syndrome?

We report on a 3-year-old Thai boy with limb, pelvic, and genital malformations. The combination of findings found in this patient is similar to that of Al-Awadi/Raas-Rothchild syndrome (AARRS) or limb/pelvis hypoplasia/aplasia syndrome. The upper limbs are more severely affected than the lower ones. Unlike that of AARRS, the radial ray is more severely affected than the ulnar ray. The presence of humeroulnar synostosis and humero-ulnar-radial synostosis and the absence of a radius distinguishes it from AARRS. The similarities and dissimilarities between the features in the present patient and other limb-pelvic hypoplasia/aplasia syndromes are discussed. The findings in this group of patients appear to demonstrate limb-pelvis-genital organ developmental field defects.

Prenatal diagnosis of femur-fibula-ulna complex by ultrasound examination at 20 weeks of gestation

We describe the prenatal sonographic diagnosis of femur-fibula-ulna complex at 20 weeks of gestation. On targeted ultrasound examination, a severe malformation of the lower limbs was observed. Further sonographic exploration demonstrated bilateral asymmetrical femoral hypoplasia, hypoplasia of both tibiae, bilateral aplasia of the fibulae and oligosyndactyly of the right hand with absence of the 4th and 5th rays. The prenatal sonographic features and differential diagnosis are discussed.

Tail gut endoderm and gut/genitourinary/tail development: a new tissue-specific role for Hoxa13

Hoxa13 is expressed early in the caudal mesoderm and endoderm of the developing hindgut. The tissue-specific roles of Hoxa13 function have not been described. Hand-foot-genital syndrome, a rare dominantly inherited human malformation syndrome characterized by distal extremity and genitourinary anomalies, is caused by mutations in the HOXA13 gene. We show evidence that one specific HOXA13 mutation likely acts as a dominant negative in vivo. When chick HFGa13 is overexpressed in the chick caudal endoderm early in development, caudal structural malformations occur. The phenotype is specific to HFGa13 expression in the posterior endoderm, and includes taillessness and severe gut/genitourinary (GGU) malformations. Finally, we show that chick HFGa13 negatively regulates expression of Hoxd13 and antagonizes functions of both endogenous Hoxa13 and Hoxd13 proteins. We suggest a fundamental role for epithelial specific expression of Hoxa13 in the epithelial-mesenchymal interaction necessary for tail growth and posterior GGU patterning.

Limb-pelvis hypoplasia/aplasia: a discrete entity in the fibuloulnar developmental field complex

The limb-pelvis hypoplasia/aplasia (LPHA) syndrome is a rare condition of skeletal malformations affecting the ulnae, pelvic bones, fibulae and femora, sometimes associated with extraskeletal defects. Most reported patients are from the Middle East, and autosomal recessive inheritance was clearly demonstrated on the basis of multiple occurrences of affected sibs born to consanguineous matings. Here we report on a baby girl presenting with the phenotypic characteristics of LPHA. This is second observation of LPHA from Italy, and the fourth outside the Middle East. A paternal first cousin once removed had unilateral fibular hypoplasia and absence of the the 4th and 5th digital rays. The possible link between these cases is discussed in the light of the developmental field theory.

Zimmer phocomelia: delineation by principal coordinate analysis

We present a 46,XX stillborn fetus with tetraphocomelia, absence of ears, severe hypoplasia of nose, cleft palate, pulmonary hypoplasia, imperforate anus and vagina, and phallus-like structure on an otherwise undefined perineum. The pattern of abnormalities resembles the tetraphocomelic condition described by Zimmer et al. in 1985. Tetraphocomelia, ear/nose hypoplasia with facial clefts, pulmonary hypoplasia, and defects of the caudal end including imperforate anus, and abnormal genitalia constitute a distinct pattern of malformation termed Zimmer phocomelia. Principal coordinate analysis with Gower's similarity index supported the clinical impression that cases reported by Zimmer and the present case are distinct from other phocomelic conditions. Although Zimmer phocomelia is currently referred to as "X-linked amelia," documentation of a female case with a penis-like structure in this report as well as consanguinity in the original family in Zimmer's report indicates that this condition is likely inherited in an autosomal recessive fashion. Zimmer phocomelia may be a more appropriate name than X-linked amelia.

Phocomelia, ectrodactyly, skull defect and urinary system anomaly: Schinzel-phocomelia syndrome?

This report describes a girl with phocomelia of the right upper limb, ectrodactyly, sacral hypoplasia and a large skull defect, but with normal growth and mental development. Ultrasonography and intravenous pyelography showed bilateral hydronephrosis and dilated ureters. We conclude that this patient may represent Schinzel-phocomelia syndrome with additional urinary tract anomalies.

Bilateral ulnar agenesis: case report and review of the literature

Bilateral ulnar agenesis is a rare abnormality. A total of 36 cases are analyzed: 35 of these are documented in the literature and 1 stillborn male is presented in this study. Most patients had one of the three conditions: Al-Awadi/Raas-Rothschild syndrome, syndrome of ulnar aplasia with split hand/split foot deformity, or the Brachmann-de Lange syndrome. Fifty percent of all cases with bilateral ulnar agenesis were associated with lower limb defects and these cases, for the most part, also belonged to the aforementioned syndromes. Nonskeletal, internal organ malformations were identified in 34% of all patients. Nine patients presented with isolated bilateral ulnar agenesis. The Al-Awadi/Raas-Rothschild syndrome and the split hand/split foot deformity are heritable disorders. There was no evidence for genetic etiology in most of the other cases. Bilateral ulnar agenesis in our fetus was part of the Brachmann-de Lange syndrome with associated cardiac defect, diaphragmatic hernia, and umbilical artery agenesis.

Severe case of Al Awadi/Raas-Rothschild syndrome or new, possibly autosomal recessive facio-skeleto-genital syndrome

A Sicilian girl whose parents were first cousins had a severe tetramelic limb deficiency (amelia of lower limbs, peromelia of upper limbs) and other defects including cleft lip and palate, facial anomalies, athelia, low umbilicus, bladder exstrophy, no external genitalia, and anteriorly displaced anus. This probably represents a particularly severe case of Al Awadi/Raas-Rothschild syndrome (limb/pelvis-hypoplasia/aplasia syndrome, LPHAS), but the possibility of a new autosomal recessive facio-skeleto-genital syndrome cannot be excluded.

The possible Middle East origin of the mutation for the limb/pelvis-hypoplasia/aplasia syndrome

Images

Autosomal recessive disorders among Arabs: an overview from Kuwait

Kuwait has a cosmopolitan population of 1.7 million, mostly Arabs. This population is a mosaic of large and small minorities representing most Arab communities. In general, Kuwait's population is characterized by a rapid rate of growth, large family size, high rates of consanguineous marriages within the Arab communities with low frequency of intermarriage between them, and the presence of genetic isolates and semi-isolates in some extended families and Bedouin tribes. Genetic services have been available in Kuwait for over a decade. During this time it has become clear that Arabs have a high frequency of genetic disorders, and in particular autosomal recessive traits. Their pattern is unique and some disorders are relatively common. Examples are Bardet-Biedl and Meckel syndromes, phenylketonuria, and familial Mediterranean fever. A relatively large number of new syndromes and variants have been delineated in Kuwait's population, many being the result of homozygosity for autosomal recessive genes that occurred because of inbreeding. Some of these syndromes have subsequently been found in other parts of the world, negating the concept of the private syndrome. This paper provides an overview of autosomal recessive disorders among the Arabs in Kuwait from a personal perspective and published studies, and highlights the need for genetic services in Arab countries with the goal of prevention and treatment of genetic disorders.

The newly recognised limb/pelvis-hypoplasia/aplasia syndrome: report of a Bedouin patient and review

A Bedouin infant born to consanguineous parents and grandparents is reported. She had Müllerian aplasia and the phenotypic features of the limb/pelvis-hypoplasia/aplasia syndrome (MIM 276820). Phenotypic variability of this newly recognised syndrome is briefly discussed.

Limb/pelvis-hypoplasia/aplasia syndrome (Al-Awadi/Raas-Rothschild syndrome): report of two Italian sibs and further confirmation of autosomal recessive inheritance

A third family with two Italian neonates affected with limb/pelvis-hypoplasia/aplasia syndrome is reported. The disorder shows autosomal recessive inheritance.

Fuhrmann syndrome of right-angle bowed femora, absence of fibulae and digital anomalies: two further cases

We describe 2 patients with bilateral right-angle bowing of femora, absence of fibulae, and reduced, flattened and nail-less toes and symmetrical fingernail deficiency in a consanguineous family of ethnic South Vietnamese Baptists and a non-consanguineous Polish family. These cases are similar to those reported by Fuhrmann et al. (in "Skeletal Dysplasias," New York: Alan R. Liss, Inc., pp 519-524), indicating possible autosomal recessive inheritance of this rare non-lethal limb malformation syndrome.

The wrinkly skin syndrome: a report of a case and review of the literature

A 2 1/2-year-old boy born of Jewish Moroccan parents is reported with physical findings of wrinkled skin on the dorsum of the hands and feet, with poor skin elasticity, syndactyly, mild kyphosis and poor muscle tone, the diagnosis being the wrinkly skin syndrome. All reported cases of this heritable disorder of connective tissue are reviewed and discussed in terms of genetics, ethnic clustering and differential diagnosis.