Osteodysplastic primordial dwarfism type II with normal intellect but delayed central nervous system myelination

Striking hematological abnormalities in patients with microcephalic osteodysplastic primordial dwarfism type II (MOPD II): a potential role of pericentrin in hematopoiesis

BACKGROUND

Microcephalic osteodysplastic primordial dwarfism type II (MOPD II) is a rare primordial dwarfism that is similar to Seckel syndrome. Seckel syndrome is known to be associated with various hematological abnormalities; however, hematological findings in MOPD II patients have not been previously reported. The present study aimed to describe the hematological findings in a series of eight patients with MOPD II from a single center.

MATERIALS AND METHODS

The study included eight patients with MOPD II that were analyzed via molecular testing, and physical and laboratory examinations.

RESULTS

Molecular testing showed that seven of the eight patients had pericentrin (PCNT) gene mutations. Hematological evaluation showed that 7 (87.5%) patients had thrombocytosis, 6 (75%) had leukocytosis, 5 (62.5%) had both leukocytosis and thrombocytosis, and 2 (25%) had anemia.

CONCLUSIONS

We report leukocytosis and thrombocytosis as a common hematologic abnormality in patients with MOPD II. The present findings may improve our understanding of the potential function of the PCNT gene in hematopoietic cell proliferation and differentiation.

Neurologic aspects of microcephalic osteodysplastic primordial dwarfism type II

Microcephalic osteodysplastic primordial dwarfism type II is a specific disorder characterized by severe intrauterine and postnatal growth retardation, acquired microcephaly, cerebrovascular abnormalities, progressive bone dysplasia, and a characteristic face. Whereas the diagnostic features of this syndrome are well-recognized, the neurologic aspects have not been clearly defined. We report on a detailed neurodevelopmental follow-up study of a new case of microcephalic osteodysplastic primordial dwarfism type II, followed from the first years of life to adolescence, and we discuss the neurocognitive features of our patient. We also review the neurologic aspects of this disorder compared with syndromes with overlapping phenotypes, such as microcephalic osteodysplastic primordial dwarfism types I and III and Seckel syndrome.

Genetic, physiologic and ecogeographic factors contributing to variation in Homo sapiens: Homo floresiensis reconsidered

A new species, Homo floresiensis, was recently named for Pleistocene hominid remains on Flores, Indonesia. Significant controversy has arisen regarding this species. To address controversial issues and refocus investigations, I examine the affinities of these remains with Homo sapiens. Clarification of problematic issues is sought through an integration of genetic and physiological data on brain ontogeny and evolution. Clarification of the taxonomic value of various 'primitive' traits is possible given these data. Based on this evidence and using a H. sapiens morphological template, models are developed to account for the combination of features displayed in the Flores fossils. Given this overview, I find substantial support for the hypothesis that the remains represent a variant of H. sapiens possessing a combined growth hormone-insulin-like growth factor I axis modification and mutation of the MCPH gene family. Further work will be required to determine the extent to which this variant characterized the population.

Homo floresiensis: Microcephalic, pygmoid, Australopithecus, or Homo?

The remarkable partial adult skeleton (LB1) excavated from Liang Bua cave on the island of Flores, Indonesia, has been attributed to a new species, Homo floresiensis, based upon a unique mosaic of primitive and derived features compared to any other hominin. The announcement precipitated widespread interest, and attention quickly focused on its possible affinities. LB1 is a small-bodied hominin with an endocranial volume of 380-410 cm3, a stature of 1m, and an approximate geological age of 18,000 years. The describers [Brown, P., Sutikna, T., Morwood, M.J., Soejono, R.P., Jatmiko, Wayhu Saptomo, E., Awe Due, R., 2004. A new small-bodied hominin from the Late Pleistocene of Flores, Indonesia. Nature 431, 1055-1061] originally proposed that H. floresiensis was the end product of a long period of isolation of H. erectus or early Homo on a small island, a process known as insular dwarfism. More recently Morwood, Brown, and colleagues [Morwood, M.J., Brown, P., Jatmiko, Sutikna, T., Wahyu Saptomo, E., Westaway, K.E., Awe Due, R., Roberts, R.G., Maeda, T., Wasisto, S., Djubiantono, T., 2005. Further evidence for small-bodied hominins from the Late Pleistocene of Flores, Indonesia. Nature 437, 1012-1017] reviewed this assessment in light of new material from the site and concluded that H. floresiensis is not likely to be descended from H. erectus, with the genealogy of the species remaining uncertain. Other interpretations, namely that LB1 is a pygmy or afflicted with microcephaly, have also been put forward. We explore the affinities of LB1 using cranial and postcranial metric and non-metric analyses. LB1 is compared to early Homo, two microcephalic humans, a 'pygmoid' excavated from another cave on Flores, H. sapiens (including African pygmies and Andaman Islanders), Australopithecus, and Paranthropus. Based on these comparisons, we conclude that it is unlikely that LB1 is a microcephalic human, and it cannot be attributed to any known species. Its attribution to a new species, Homo floresiensis, is supported.

Pachygyria in a girl with microcephalic osteodysplastic primordial short stature type II

We report a mild form of lissencephaly or a pachygyric brain in a girl with microcephalic osteodysplastic primordial 'dwarfism' (MOPD) type II. She was born with severe intrauterine growth failure. A diagnosis of MOPD type II was warranted by persistent postnatal growth failure, microcephaly with a Seckel-like facial appearance, and distinctive radiological findings, including overtubulation of the long bones, metaphyseal cupping of the distal femora, and brachyphalangy with ivory epiphyses. Brain MRI showed thickened cerebral cortices with few and large gyri, most prominently in the frontal and posterior temporal regions. The Sylvian fissures developed incompletely, and the posterior horns of the lateral ventricle were dilated (colpocephaly). Despite the severe imaging findings, she showed only mild retardation of psychomotor development. To date, only minor brain malformations have attracted attention in MOPD type II. Our experience may suggest a wider spectrum of brain anomalies in this entity.

Majewski osteodysplastic primordial dwarfism type II (MOPD II): natural history and clinical findings

A description of the clinical features of Majewski osteodysplastic primordial dwarfism type II (MOPD II) is presented based on 58 affected individuals (27 from the literature and 31 previously unreported cases). The remarkable features of MOPD II are: severe intrauterine growth retardation (IUGR), severe postnatal growth retardation; relatively proportionate head size at birth which progresses to true and disproportionate microcephaly; progressive disproportion of the short stature secondary to shortening of the distal and middle segments of the limbs; a progressive bony dysplasia with metaphyseal changes in the limbs; epiphyseal delay; progressive loose-jointedness with occasional dislocation or subluxation of the knees, radial heads, and hips; unusual facial features including a prominent nose, eyes which appear prominent in infancy and early childhood, ears which are proportionate, mildly dysplastic and usually missing the lobule; a high squeaky voice; abnormally, small, and often dysplastic or missing dentition; a pleasant, outgoing, sociable personality; and autosomal recessive inheritance. Far-sightedness, scoliosis, unusual pigmentation, and truncal obesity often develop with time. Some individuals seem to have increased susceptibility to infections. A number of affected individuals have developed dilation of the CNS arteries variously described as aneurysms and Moya Moya disease. These vascular changes can be life threatening, even in early years because of rupture, CNS hemorrhage, and strokes. There is variability between affected individuals even within the same family.

A variant microcephalic osteodysplastic slender-bone disorder with growth hormone deficiency and a pigmentary retinopathy

We present the case of a 3-year-old boy with post-natal growth failure, microcephaly, developmental delay, facial dysmorphism, an evolving pigmentary retinopathy, pituitary hypoplasia, micropenis, and growth hormone (GH) deficiency. He has a microcephalic osteodysplastic slender-bone disorder with disharmonic delayed osseous maturation, most closely resembling patients with microcephalic osteodysplastic primordial dwarfism type II (MOPD II). Intrauterine growth retardation, a universal finding in the MOPD II, was absent in our patient.

Microcephalic osteodysplastic primordial dwarfism type II: report of three cases and review

We report on three further patients with microcephalic osteodysplastic dwarfism type II. All children have marked intrauterine and postnatal growth failure, microcephaly, and mental and statomotor retardation. They are disproportionately short statured due to short limbs. Characteristic skeletal abnormalities are small iliac wings with flat acetabular angles, coxa vara, V-shaped distal femoral metaphyses, and triangular distal femoral epiphyses, as well as pseudoepiphyses of metacarpals, short first metacarpals, and brachymesophalangy V. At age 3 years, bilateral epiphyseolysis of the femoral heads occurred in case 1. Including our patients, 17 cases have been published so far. We review the clinical picture and the cause.