Familial aplasia/hypoplasia of pelvis, femur, fibula, and ulna with abnormal digits in an inbred Pakistani Muslim family: A possible new autosomal recessive disorder with overlapping manifestations of the syndromes of Fuhrmann, Al-Awadi, and Raas-Rothschild

A novel homozygous missense mutation (c.610G>A, p.Gly204Ser) in the WNT7A gene causes tetra-amelia in two Saudi families

Fuhrmann syndrome and Al-Awadi/Raas-Rothschild/Schinzel (AA/RRS) phocomelia syndrome are rare autosomal recessive inherited disorders characterized by aplastic/hypoplastic nails with ectopic dorsal palms, absence of humeri, hypoplastic ulnae, and bowed short radii with the elbow joints present, shown to result from missense mutations in WNT7A (p.Ala109Thr and p.Arg292Cys). Here, we describe three affected individuals belonging to two related Saudi Arabian families. All three have a similar phenotype characterized by pelvic dysplasia and truncated lower limbs compatible with the clinical diagnosis of AA/RRS. The upper limbs were more variable: one patient individual had complete amelia, whereas the others had variable limb malformations and all had absence of nails and the ventralization of the palms/digits. All affected individuals were homozygous for a mutation in exon 4 of WNT7A (c.610G>A) resulted in substitution of a highly conserved glycine to serine (p.Gly204Ser) within the Wnt signature motif [C-K-C-H-G-V-S-G-S-C]. This report describes a third cases/family in the literature with variable phenotype of AA/RRS and Fuhrmann syndrome. Identification of this mutation further underlines the crucial involvement of WNT7A in the limb development. This novel missense homozygous mutation (p.Gly204Ser) in the WNT7A gene is a unique mutation in the degree of loss of function in the upper limb development which ranges from mild to complete absence of both upper limbs (amelia). Moreover, all three affected individuals had genitourinary anomalies, linking WNT7A function to genitourinary development.

A previously undescribed syndrome combining fibular agenesis/hypoplasia, oligodactylous clubfeet, anonychia/ungual hypoplasia, and other defects

We describe an apparently new genetic syndrome in six members of a family living in a remote area in Northeastern Brazil. This syndrome comprises: short stature due to a marked decrease in the length of the lower limbs (predominantly mesomelic with fibular agenesis/marked hypoplasia), grossly malformed/deformed clubfeet with severe oligodactyly, upper limbs with acromial dimples and variable motion limitation of the forearms and/or hands, severe nail hypoplasia/anonychia sometimes associated with mild brachydactyly and occasionally with pre-axial polydactyly. This syndrome is apparently distinct from the syndrome of brachydactyly-ectrodactyly with fibular aplasia or hypoplasia (OMIM 113310), the syndrome of fibular aplasia or hypoplasia, femoral bowing and poly-, syn-, and oligodactyly (OMIM 228930), and from other previously described conditions exhibiting fibular agenesis/hypoplasia.

Preimplantation genetic diagnosis for severe albright hereditary osteodystrophy

CONTEXT

Preimplantation genetic diagnosis (PGD) enables the selection of embryos without mutations for implantation and has not been described to our knowledge for mutations in GNAS. Phocomelia in a patient with Albright hereditary osteodystrophy (AHO) has also not been previously described.

OBJECTIVE

The aim of this study was to identify a GNAS mutation in a patient with a severe form of AHO and pseudohypoparathyroidism type 1a with phocomelia and to perform PGD on embryos derived by in vitro fertilization to deliver an unaffected infant.

DESIGN

A proband and his family are described clinically, the GNAS gene was sequenced to identify a novel mutation in the proband, and PGD was performed on embryos.

SETTING

The setting was in a tertiary-care hospital.

PATIENTS

The patients were from a single family in which the proband has a severe form of AHO.

INTERVENTIONS

Interventions were PGD and in vitro fertilization.

MAIN OUTCOME MEASURES

The main outcome measures were the clinical phenotypes and GNAS gene sequences of the proband, embryos, and family members.

RESULTS

After PGD, three genotypically normal embryos were transferred back to the mother. Pregnancy ensued, and a healthy male infant was delivered at 36.5 wk gestation. The GNAS genes in the baby were confirmed as wild-type, and the infant is free of any signs of AHO.

CONCLUSIONS

We describe herein a proband with AHO and severe skeletal deformities (including phocomelia) related to a novel GNAS mutation and the delivery of a male infant with homozygous normal GNAS genotype after PGD.

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.

Mutations in WNT7A cause a range of limb malformations, including Fuhrmann syndrome and Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome

Fuhrmann syndrome and the Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome are considered to be distinct limb-malformation disorders characterized by various degrees of limb aplasia/hypoplasia and joint dysplasia in humans. In families with these syndromes, we found homozygous missense mutations in the dorsoventral-patterning gene WNT7A and confirmed their functional significance in retroviral-mediated transfection of chicken mesenchyme cell cultures and developing limbs. The results suggest that a partial loss of WNT7A function causes Fuhrmann syndrome (and a phenotype similar to mouse Wnt7a knockout), whereas the more-severe limb truncation phenotypes observed in Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome result from null mutations (and cause a phenotype similar to mouse Shh knockout). These findings illustrate the specific and conserved importance of WNT7A in multiple aspects of vertebrate limb development.

Light microscopic, immunohistochemical, and ultrastructural findings in congenital fibular aplasia or hypoplasia (FAH)

Congenital aplasia or hypoplasia of the fibula (FAH) is a rare malformation that is defined by a partial or complete absence of the fibular bone. Etiology and pathogenesis are unknown and the precise morphology of the tissue cord replacing the malformed fibula has not been well described. Therefore, tissue cord was examined in 8 patients with FAH. Light microscopic, immunohistochemical, and electron microscopic investigations showed a core of embryonic cartilage with collagen II and VI expressions surrounded by connective tissue. Although collagen II expression is typical for chondroid differentiation, collagen VI reactivity is normally seen in articular cartilage and tendon-like fibrocartilaginous tissue but is absent in hyaline cartilage. Further ultrastructural analyses by electron microscopy supported these findings. The histomorphologic changes correspond to the histologic findings of Papenbrock et al. (2000, Mech Dev 92:113-123) who produced a congenital malformation in transgenic mice that resembled FAH by overexpression of Hox c11.

Isolated femoral hypoplasia: an intrauterine differential diagnosis to campomelia

The isolated form of femoral bowing is an important differential diagnosis of campomelia. Therefore, knowledge of isolated anomalies is fundamental for prenatal diagnosis, especially for the differential diagnosis from severe syndromes. Four cases are presented to discuss the differential diagnosis of femoral bowing including a review of the literature. We report four newborn babies with unilateral bowing and shortening of the femur. Three had no further anomaly; one child had additional abnormalities due to coumarin embryopathy. The radiological findings were shortened femora with bowing and varus deformity and cortical thickening on the concave side. All other parts showed normal bone structure. The aetiology of femoral bowing is unknown. Early damage of the cartilaginous model followed by remodelling with thickening on the concave side of the bone similar to the healing of malaligned fractures is suspected. The isolated form of femoral bowing without any other anomalies has to be differentiated from complex and more often severe congenital syndromes such as campomelia. Postpartum radiological examination should be reduced to a single exposure of the affected limb and follow-up should be done by clinical examination.

Fibular aplasia, tibial campomelia, and oligosyndactyly in a male newborn infant: A case report and review of the literature

We report on a male newborn with a rarely described congenital limb deficiency syndrome consisting of shortening and anterior bowing of the right lower limb at the distal third of the tibia with associated overlying soft tissue dimpling, oligodactyly of the right foot, and a left-sided oligosyndactyly of the hand. The right hand and left lower limb were clinically normal. Radiographic examination revealed complete absence of the right fibula, absence of the right-sided Vth ray, and anterior bowing and shortening of the right-sided tibia. Femora, humeri, ulnae, and radii were normal. The infant had neither facial dysmorphia nor other associated anomalies. A limb deficiency syndrome comparable to this case has been reported in a female by Hecht and Scott, the only report classified under OMIM 246570 so far. We found two other reports describing three cases comparable to our case and the female reported by Hecht and Scott, and reviewed these cases. The major common findings in all the five cases consist of fibular aplasia, tibial campomelia, and oligosyndactyly. Therefore, we propose to name it fibular aplasia-tibial campomelia-oligosyndactyly (FATCO) syndrome. Additional case reports are needed for further delineation of this rare limb deficiency syndrome.

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.

Grebe-Quelce-Salgado chondrodystrophy: prenatal diagnosis of two new cases in unrelated families in Southern Brazil

Grebe-Quelce-Salgado chondrodystrophy is an autosomal recessive non-lethal skeletal dysplasia. Affected individuals have normal head, neck, and trunk skeleton, relatively normal humeri and femora, short and deformed radii, ulnae, tibiae, and fibulae, and severe abnormalities of hands and feet. Polydactyly is frequent. Digits present as globular appendages and are characteristic of the condition. The disease is caused by a missense mutation in the gene encoding cartilage-derived morphogenetic protein-1 (CDMP-1). Most cases described in the literature are from Brazil and, among these, all had ancestors from a particular region in the state of Bahia. We describe two cases of Grebe-Quelce-Salgado chondrodystrophy visualized by prenatal ultrasound. The patients presented in this report do not descend from the population of Bahia and, to our knowledge, case two is the only case with prenatal clinical diagnosis in a family with no previously affected children.