[Role of signs of fetal hypokinesia in the diagnosis of spinal muscular atrophy of neonatal onset].
BACKGROUND
Spinal muscular atrophy (SMA) is characterized by early degeneration of anterior horn cells. The most frequent and severe type of neonatal onset is Werdnig-Hoffmann disease. The neurologic and genetic characteristics of SMA are well-known. The aim of this study was to analyze the dysmorphologic features of this disease.


METHODS
We present an analysis of 10 cases of SMA identified among 27,864 infants with congenital defects registered by the Spanish Collaborative Study of Congenital Malformations (ECEMC) between April 1976 and December 1998. We also report a clinical case of neonatal SMA presenting the classical signs of fetal hypokinesia deformation sequence.


RESULTS
The minimum estimation of the prevalence of SMA with congenital defects in our population is 0.32 per 100,000 live births. We found a male-to-female ratio of 3.5. The most frequently associated congenital defects in our population of neonatal SMA were located in the extremities (mainly arthrogryposis), face and thorax and could be explained by intrinsic fetal hypomobility secondary to the neuromuscular disorder. The characteristics of fetal hypokinesia deformation sequence are discussed in the case report presented herein: dystocic delivery, short umbilical cord, polyhydramnios, intrauterine growth retardation, craniofacial malformations, skeletal abnormalities with multiple articular contractures, pulmonary hypoplasia, etc.


CONCLUSIONS
It is important to recognize the congenital defects associated with neuromuscular disorders, because dysmorphologic features are sometimes more marked than neurologic features in the neonatal period and because of the wide spectrum of congenital defects in neonatal SMA that result in a fetal hypokinesia deformation sequence.
González De Dios
J
J
Departamento de Pediatría, Hospital Universitario San Juan, Universidad Miguel Hernández, Alicante, Spain.
Martínez Frías
M L
ML
Arroyo Carrera
I
I
Fondevilla Saucí
J
J
Sanchís Calvo
A
A
Hernández Ramón
F
F
Martínez Guardia
N
N
García González
M M
MM
D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D018476:Hypokinesia / Q000175:diagnosis* / Q000453:epidemiology; D007231:Infant, Newborn; D008297:Male; D011296:Prenatal Diagnosis; D014897:Spinal Muscular Atrophies of Childhood / Q000175:diagnosis* / Q000453:epidemiology