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Prenatal Diagnosis:
- Aymé, "et al." (1989) reported prenatal diagnosis of Fryns syndrome by sonography between 24 and 27 weeks.
- Manouvrier-Hanu et al. (1996) described the prenatal diagnosis of Fryns syndrome by ultrasonographic detection of diaphragmatic hernia and cystic hygroma. The diagnosis was confirmed after termination of the pregnancy. The fetus also had 2 erupted incisors; natal teeth had not been mentioned in other cases of Fryns syndrome.
Differential Diagnosis:
- McPherson et al. (1993) noted the phenotypic overlap between Fryns syndrome and the Pallister–Killian syndrome (601803), which is a dysmorphic syndrome with tissue-specific mosaicism of tetrasomy 12p.
- Veldman et al. (2002) discussed the differentiation between Fryns syndrome and Pallister–Killian syndrome, noting that differentiation is important to genetic counseling because Fryns syndrome is an autosomal recessive disorder and Pallister–Killian syndrome is usually a sporadic chromosomal aberration. However, discrimination may be difficult due to the phenotypic similarity. In fact, in some infants with 'coarse face,' acral hypoplasia, and internal anomalies, the initial diagnosis of Fryns syndrome had to be changed because mosaicism of isochromosome 12p was detected in fibroblast cultures or kidney tissue. Although congenital diaphragmatic hernia is a common finding in both syndromes, bilateral congenital diaphragmatic hernia had been reported only in patients with Fryns syndrome until the report of the patient with Pallister–Killian syndrome by Veldman et al. (2002).
- Slavotinek (2004) reviewed the phenotypes of 52 reported cases of Fryns syndrome and reevaluated the diagnostic guidelines. She concluded that congenital diaphragmatic hernia and distal limb hypoplasia are strongly suggestive of Fryns syndrome, with other diagnostically relevant findings including pulmonary hypoplasia, craniofacial dysmorphism, polyhydramnios, and orofacial clefting. Slavotinek (2004) stated that other distinctive anomalies not mentioned in previous guidelines include ventricular dilatation or hydrocephalus, agenesis of the corpus callosum, abnormalities of the aorta, dilatation of the ureters, proximal thumbs, and broad clavicles.
Amniotic band syndrome is considered an accidental event and it does not appear to be genetic or hereditary, so the likelihood of it occurring in another pregnancy is remote. The cause of amnion tearing is unknown and as such there are no known preventative measures.
The diagnosis of AOS is a clinical diagnosis based on the specific features described above. A system of major and minor criteria was proposed.
The combination of two major criteria would be sufficient for the diagnosis of AOS, while a combination of one major and one minor feature would be suggestive of AOS. Genetic testing can be performed to test for the presence of mutation in one of the known genes, but these so far only account for an estimated 50% of patients with AOS. A definitive diagnosis may therefore not be achieved in all cases.
Amniotic band syndrome is often difficult to detect before birth as the individual strands are small and hard to see on ultrasound. Often the bands are detected indirectly because of the constrictions and swelling upon limbs, digits, etc. Misdiagnosis is also common, so if there are any signs of amniotic bands, further detailed ultrasound tests should be done to assess the severity. 3D ultrasound and MRI can be used for more detailed and accurate diagnosis of bands and the resulting damage/danger to the fetus.
A clinical diagnosis of SCS can be verified by testing the TWIST1 gene (only gene in which mutations are known to cause SCS) for mutations using DNA analysis, such as sequence analysis, deletion/duplication analysis, and cytogenetics/ FISH analysis. Sequence analysis of exon 1 (TWIST1 coding region) provides a good method for detecting the frequency of mutations in the TWIST1 gene. These mutations include nonsense, missense, splice site mutation, and intragenic deletions/insertions. Deletion/duplication analysis identifies mutations in the TWIST1 gene that are not readily detected by sequence analysis. Common methods include PCR, multiplex ligation-dependent probe amplification (MLPA), and chromosomal microarray (CMA). Cytogenetic/FISH analysis attaches fluorescently labels DNA markers to a denatured chromosome and is then examined under fluorescent lighting, which reveals mutations caused by translocations or inversions involving 7p21. Occasionally, individuals with SCS have a chromosome translocation, inversion, or ring chromosome 7 involving 7p21 resulting in atypical findings, such as, increased developmental delay. Individuals with SCS, typically have normal brain functioning and rarely have mental impairments. For this reason, if an individual has both SCS and mental retardation, then they should have their TWIST1 gene screened more carefully because this is not a normal trait of SCS. Cytogenetic testing and direct gene testing can also be used to study gene/chromosome defects. Cytogenetic testing is the study of chromosomes to detect gains or losses of chromosomes or chromosome segments using fluorescent in situ hybridization (FISH) and/or comparative genomic hybridization (CGH). Direct gene testing uses blood, hair, skin, amniotic fluid, or other tissues in order to find genetic disorders. Direct gene testing can determine whether an individual has SCS by testing the individual's blood for mutations in the TWIST1 gene.
Carrier testing for Roberts syndrome requires prior identification of the disease-causing mutation in the family. Carriers for the disorder are heterozygotes due to the autosomal recessive nature of the disease. Carriers are also not at risk for contracting Roberts syndrome themselves. A prenatal diagnosis of Roberts syndrome requires an ultrasound examination paired with cytogenetic testing or prior identification of the disease-causing ESCO2 mutations in the family.
Up until recently, experts frequently disagreed on whether a patient had SCS, Crouzon syndrome, isolated craniosynostosis, or some other disease because the symptoms are so closely related, they literally had no way of differentiating between all of them. However, we now have direct gene testing, which allows for a more definitive diagnosis because it allows them to be differentiated from each other based on which gene is mutated in each condition. The following is a list of conditions commonly confused/misdiagnosed for SCS, some of their symptoms, and which mutated gene each contains:
Patients with abnormal cardiac and kidney function may be more at risk for hemolytic uremic syndrome
Diagnosis is based on physical examination including radiographs of the hands and feet and imaging studies of the kidneys, bladder, and female reproductive tract. HOXA13 is the only gene known to be associated with HFGS. Approximately 60% of mutations are polyalanine expansions. Molecular genetic testing is clinically available.
The overall prognosis is excellent in most cases. Most children with Adams–Oliver syndrome can likely expect to have a normal life span. However, individuals with more severe scalp and cranial defects may experience complications such as hemorrhage and meningitis, leading to long-term disability.
For most cases the diagnosis for congenital amputation is not made until the infant is born. One procedure that is helpful in determining this condition in an infant is an ultrasound examination of a fetus when still in the mother's abdomen as it can reveal the absence of a limb. However, since ultrasounds are routine they may not pick up all the signs of some of the more subtle birth defects.
The most popular method of treatment for congenital amputation is having the child be fit for a prosthesis which can lead to normal development, so the muscles don't atrophy. If there is congenital amputation of the fingers, plastic surgery can be performed by using the big toe or second toes in place of the missing fingers of the hand.
In rare cases of amniotic banding syndrome, if diagnosed "in utero", fetal surgery may be considered to save a limb which is in danger of amputation.
The diagnosis is usually based on clinical features present at birth.
Ultrasound in the second trimester may show abnormalities associates with NLS, including polyhydramnios, intrauterine growth restriction, microcephaly, proptosis and decreased fetal motility.
Studies suggest that prenatal care for mothers during their pregnancies can prevent congenital amputation. Knowing environmental and genetic risks is also important. Heavy exposure to chemicals, smoking, alcohol, poor diet, or engaging in any other teratogenic activities while pregnant can increase the risk of having a child born with a congenital amputation. Folic acid is a multivitamin that has been found to reduce birth defects.
Surgical correction is recommended when a constriction ring results in a limb contour deformity, with or without lymphedema.
The prognosis is poor; affected individuals are either stillborn or die shortly after birth. The longest survival reported in literature is of 134 days.
This syndrome is transmitted as an autosomal recessive disorder and there is a risk for recurrence of 25% in future pregnancies.
Cytogenetic preparations that have been stained by either Giemsa or C-banding techniques will show two characteristic chromosomal abnormalities. The first chromosomal abnormality is called premature centromere separation (PCS) and is the most likely pathogenic mechanism for Roberts syndrome. Chromosomes that have PCS will have their centromeres separate during metaphase rather than anaphase (one phase earlier than normal chromosomes). The second chromosomal abnormality is called heterochromatin repulsion (HR). Chromosomes that have HR experience separation of the heterochromatic regions during metaphase. Chromosomes with these two abnormalities will display a "railroad track" appearance because of the absence of primary constriction and repulsion at the heterochromatic regions. The heterochromatic regions are the areas near the centromeres and nucleolar organizers. Carrier status cannot be determined by cytogenetic testing. Other common findings of cytogenetic testing on Roberts syndrome patients are listed below.
- Aneuploidy- the occurrence of one or more extra or missing chromosomes
- Micronucleation- nucleus is smaller than normal
- Multilobulated Nuclei- the nucleus has more than one lobe
Additional findings that may be present in HFGS according to the latest research are:
- Limited metacarpophalangeal flexion of the thumb or limited ability to oppose the thumb and fifth finger
- Hypoplastic thenar eminences
- Medial deviation of the great toe (hallux varus), a useful diagnostic sign when present
- Small great toenail
- Fifth-finger clinodactyly, secondary to a shortened middle phalanx
- Short feet
- Altered dermatoglyphics of the hands; when present, primarily involving distal placement of the axial triradius, lack of thenar or hypothenar patterning, low arches on the thumbs, thin ulnar loops (deficiency of radial loops and whorls), and a greatly reduced ridge count on the fingers
Radiographic findings
- Hypoplasia of the distal phalanx and first metacarpal of the thumbs and great toes
- Pointed distal phalanges of the thumb
- Lack of normal tufting of the distal phalanges of the great toes
- Fusions of the cuneiform to other tarsal bones or trapezium-scaphoid fusion of the carpals
- Short calcaneus
- Occasional bony fusions of the middle and distal phalanges of the second, third, fourth, or fifth toes
- Delayed carpal or tarsal maturation
- Metacarpophalangeal profile reflecting shortening of the first metacarpal, the first and second phalanges, and the second phalanx of the second and fifth digits
Urogenital Defects
Females may have the following:
- Vesicoureteral reflux secondary to ureteric incompetence
- Ectopic ureteral orifices
- Trigonal hypoplasia
- Hypospadiac urethra
- Subsymphyseal epispadias
- Patulous urethra
- Urinary incontinence (related to structural anomalies and weakness of the bladder sphincter muscle)
- Small hymenal opening
- Various degrees of incomplete Müllerian fusion with or without two cervices or a longitudinal vaginal septum
Males may have the following:
- Retrograde ejaculation (related to structural anomalies and weakness of the bladder sphincter muscle)
The symptoms would appear at birth or shortly after birth. The combination of physical symptoms on the child would suggest they have CHILD syndrome. A skin sample examined under a microscope would suggest the characteristics of the syndrome and an X-Ray of the trunk, arms, and legs would help to detect underdeveloped bones. A CT scan would help detect problems of the internal organs.
In France, Aymé, "et al." (1989) estimated the prevalence of Fryns syndrome to be 0.7 per 10,000 births based on the diagnosis of 6 cases in a series of 112,276 consecutive births (live births and perinatal deaths).
When surgery is indicated, the choice of treatment is based on the classification. Table 4 shows the treatment of cleft hand divided into the classification of Manske and Halikis.
Techniques described by Ueba, Miura and Komada and the procedure of Snow-Littler are guidelines; since clinical and anatomical presentation within the types differ, the actual treatment is based on the individual abnormality.
Table 4: Treatment based on the classification of Manske and Halikis
The timing of surgical interventions is debatable. Parents have to decide about their child in a very vulnerable time of their parenthood. Indications for early treatment are progressive deformities, such as syndactyly between index and thumb or transverse bones between the digital rays. Other surgical interventions are less urgent and can wait for 1 or 2 years.
Modeling EEC syndrome in vitro has been achieved by reprogramming EEC fibroblasts carrying mutations R304W and R204W into induced pluripotent stem cell (iPSC) lines. EEC-iPSC recapitulated defective epidermal and corneal fates. This model further identified PRIMA-1MET, a small compound that was identified as a compound targeting and reactivating p53 mutants based on a cell-based screening for rescuing the apoptotic activity of p53, as efficient to rescue R304W mutation defect. Of interest, similar effect had been observed on keratinocytes derived from the same patients. PRIMA-1MET could become an effective therapeutic tool for EEC patients.
Further genetic research is necessary to identify and rule out other possible loci contributing to EEC syndrome, though it seems certain that disruption of the p63 gene is involved to some extent. In addition, genetic research with an emphasis on genetic syndrome differentiation should prove to be very useful in distinguishing between syndromes that present with very similar clinical findings. There is much debate in current literature regarding clinical markers for syndromic diagnoses. Genetic findings could have great implications in clinical diagnosis and treatment of not only EEC, but also many other related syndromes.
At the beginning of the surgery a tourniquet will be applied to the limb. A tourniquet compresses and control the arterial and venous circulation for about 2 hours. The constriction band must be dissected very carefully to avoid damaging the underlying neurovasculature. When the constriction band is excised, there will be a direct closure. This allows the fatty tissue to naturally reposition itself under the skin.
“With complete circumferential constriction bands, it is recommended that a two-stage correction approach be used. At the first operation, one-half of the circumference is excised and the other one-half can be excised after three to six months. This will avoid any problems to the distal circulation in the limb, which may already be compromised. Lymphedema, when present, will significantly improve within a few weeks of the first surgery.”
For the direct closure of the defect after dissecting a constriction band there are two different techniques:
1. Triangular flaps; For this technique the circumference between the two borders must be measured. Depending on the difference the number of triangular flaps can be decided. With a triangular flap you can create more skin.
2. Z/W-plasty; “Z-plasty is a plastic surgery technique that is used to improve the functional and cosmetic appearance of scars. It can elongate a contracted scar or rotate the scar tension line. The middle line of the Z-shaped incision (the central element) is made along the line of greatest tension or contraction, and triangular flaps are raised on opposite sides of the two ends and then transposed.”
In rare cases, if diagnosed in utero, fetal surgery may be considered to save a limb that is in danger of amputation or other deformity. This operation has been successfully performed on fetuses as young as 22 weeks. The Melbourne's Monash Medical Centre in Australia, as well as multiple facilities in the United States of America, have performed successful amniotic band release surgery.
The incidence of VACTERL association is estimated to be approximately 1 in 10,000 to 1 in 40,000 live-born infants. It is seen more frequently in infants born to diabetic mothers. While most cases are sporadic, there are clearly families who present with multiple involved members.
Tetra-amelia syndrome has been reported in only a few families worldwide.
According to a 2011 study by Bermejo-Sanchez, amelia – that is, the lacking of one or more limbs – occurs in roughly 1 out of every 71,000 pregnancies.