Glossary in Congenital Malformations

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#Field defects: "The result of (non-disruptive) disturbed development of a morphogenic field or of a part thereof," or a "...dysmorphogenetically reactive unit, i.e., a set of embryonic primordia that reacted identically to different dysmorphogenetic causes". The connections between primary cause and multiple consequences are less well defined than for sequences, but field defects have more limited and reproducible consequences than are typical in syndromes. Excamples include holoprosencephaly spectrum of anomalies and caudal regression.

#"Floppy infant": infants with severe hypotonia. This entities include spinal muscular atrophy and others conditions.

#Hamartoma: A benign tumor-like nodule composed of an overgrowth of mature cells and tissues normally present in the affected part, but often with one element predominanting. See also choristoma.

Syndromes and Sequences: Head

#Fetal alcohol syndrome (FAS):

Summary: Fetal alcohol syndrome is resulted from the teratogenic effects of alcohol on human fetuses. The classic cases have the clinical triad of growth retardation, characteristic facial dysmorphology and dysfunction of the central nervous system. The degree of involvement is highly variable.

Definition: Patients must have all three chraracteristics: prenatal and postnatal growth retardation (<2 SD for length and weight), characteristic facial features, and CNS dysfunction.

· FAE: When the features of the syndrome are not fully expressed, the term fetal alcohol effects (FAE) can be used.

Clinical features: FAS is rarely lethal. Patients have mental retardation and characteristic facial features. Congenital heart diseases and skeletal malformations may also be present.

Diagnostic criteria:

· Prenatal and/or postnatal growth retardation (weight, length, and/or head circumference below the 10^th percentile).

· Characteristic facial dysmorphology with at least two of these three signs: microcephaly (head circumference below the 3^rd percentile), microophthalommia and/or short palpebral fissures, and poorly developed philtrum, thin upper lip, and flattening of the maxillary area.

· Central nervous system involvement (signs of neurological abnormality, developmental delay, or intellectual impairment).

Ocular: Retinal ganglion cell loss.

Reference: [Rosett HL, 1980; Stratton KR et al., 1996]

#Fetal dyskinesia deformation sequence: this is seen in babies with severe dyskinesia including arthrogryposis multiplex congenita, "floppy infants", and multiple lethal pterygia syndrome. These syndromes are associated with a large number of syndromic, osteochondrodysplastic, chondrodysplastic, metabolic, hypoxic-ischemic, degenerative, and connective tissue disorders. The clinical features include, in addition to etiher the joint abnormalities or hypotonia, a long thin body habitus, myopathic facies with recessed chin, tented mouth, high-arched palate, low-set earscrytporchidism, and pulmonary hypoplasia due to poor functioning of respiratory muscles. Polyhydramnios may be present due to poor swallowing in utero.

#Foix-Chavany-Marie syndrome (bilateral peri-Sylvian syndrome): This is a localized migration disorder, also known as facio-pharyngoglossomasticatory diplegia with voluntary-autonomic dissociation. This syndrome may be produced by polymicrogyria in anterior opercular or peri-Sylvian area.

#Fowler's sybdrome (proliferative vasculopathy and hydranencephaly-hydrocephaly with limb pterygia): This is a lethal, probably autosomal recessive. Features include large head and multiple joint pterygia. The brain is hydrocephalic with the cerebral hemispheres transformed into a thin cerebral mantle with dystrophic calcification. There is a marked deficiency of young neurons and the ganglionic eminence is a vertige. The penetrating vessels are abnormal and often form glomeruloids.

It is very important to differentiate Fowler's syndrome from sporadic encephaloclastic form of hydranencephaly from which it is ultrasonographically & macroscopically indistinguishable.
Clinical: recurrent intrauterine death or therapeutic abortion of pregnancy following sonographic demonstration of "hydrancephaly".
GROSS PATHOLOGY: Abortus with severe arthrogyposis, ptergyria, muscular hypoplasia, and massive cystic dilataion of the ventricle.
Histology: the residual cortex is very thin but maintains a certain extent of normal organization. There are glomeruloid vascular proliferations in all part of the CNS including the retina but not in leptomeninges or other tissus. Characteristic: pathogonomic glomeruloid vascular proliferation composed of inclusion- bearing endothelial cells in the residual cortex. Calcifications are particularly massive near the ventricular surface of the basal ganglia.

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