The inheritance of the hereditary motor and sensory neuropathies (HMSN) is usually autosomal dominant. We studied a kinship with a pattern of X-linked dominant inheritance. The phenotype was similar to HMSN of the "intermediate" type. Men were more severely affected than women, and hypertrophic nerves were not found. Nerve conduction was very slow in men, but it was mildly slow or normal in women. No male-to-male transmission was found in six generations.
Craniolacunia, also known as lacunar skull defects or Lückenschadel, are rounded or fingerlike defects in ossification in the inner table of the membranous calvarium which are surrounded by strips of normal bone [Vogt and Wyatt, 19411. Over 80% of newborns with spina bifida have craniolacunia apparent on skull radiograph [Shopfner et al, 1965; Tajima et al, 19771. The radiographic abnormality becomes less apparent during the first 6 months of life and is usually not seen in older infants with spina bifida [McRae, 19661. The etiology of craniolacunia in infants with spina bifida is uncertain. Several of the hypotheses which have been suggested relate to abnormalities in intracranial pressure. Faust [ 193 11 proposed that craniolacunia result from an imbalance of pressures on the developing cranium consisting of a relative increase in externa1 pressure from the intrauterine environment because of diminished intracranial pressure secondary to the "pressure valve" effect of the myelomeningocele sac. This pressure imbalance would produce areas of atrophy of the developing cranium. Others have suggested that increased intracranial pressure, perhaps causing ischemic changes in the developing cranium, is the cause of craniolacunia [Engstler, 1905;Kerr, 1933; Rothbart, 19361. The finding of normal head circumferences at birth in most infants with spina bifida seems to conflict with both of these hypotheses [Tajima et al, 1977; Stein et al, 19741. Such measurements made at birth may not reflect pressure phenomena occurring during early fetal development or during the onset of cranial ossification. If the fetal biparietal diameters (BPDs), measured at midtrimester, of infants with spina bifida were significantly larger or smaller than those of unaffected infants, this might favor either the effects of increased intracranial pressure or those of intracranial decompression on fetal head size.Prospective studies of BPD at midtrimester in fetuses with spina bifida ascertained through maternal semm alpha-fetoprotein screening have shown that the BPDs in these fetuses are significantly less than those of corresponding control pregnancies, even in those infants with evidence of early ventricular dilatation in utero Wald et al,
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