Shannon Higgins 
a
special girl born with Polymicrogyria (PMG)
Shannon Higgins
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The University of Chicago Dear Kay: Shannon was seen at the Lissencephaly Network meeting in Dallas, TX on July 1-4, 1999. She is a 1-year-old girl with macrocephaly, developmental delay and atypical cortical dysplasia which most closely resembles polymicrogyria (PMG). It seems to differ as the gyral pattern seems accentuated rather than diminished in some areas, and the usual pattern of microgyri and microsulci is not obvious. She did not seem to fit any well delineated malformation syndrome such as Sotos syndrome. The family history is notable for a maternal first cousin (child of a maternal uncle) with pervasive developmental disorder. Family history is also notable for cancer of the lung and early myocardial infarctions. She was born after an uncomplicated pregnancy to a 37-year-old gravida 4, pare 2-3 mother who has had one spontaneous abortion. There were no illnesses during the pregnancy, and no medications were used. Labor and delivery occurred at 38 weeks gestation, and were uncomplicated. Her Apgar scores were good and she went home with mother after a couple days. Her birth weight was 9#. There have been no major medical problems. At 10 months of age, delay in development and a misshapen head were noted. She has continued to make developmental progress albeit slow At the present time, she is able to roll over, sit with assistance and make some raspberry sounds but no other consonant sounds. On physical exam, her length was 74.5 cm. (near the god percentile) and weight was 11.3 kg. (greater than the 98th percentile). Her head circumference was 50.0 cm which is much greater than the 98'h percentile. There was some flattening of the right occipital region and some mid-facial abnormalities consisting of slightly prominent forehead and hypertelorism. She had an intercanthal distance of 3.1 which is greater than the 97th percentile and an outer canthal distance of 8.5 cm which is also greater than the 97th percentile. Her nose was short and slightly anteverted. Her mouth was wide and the oral cavity appeared to be normal. She had some breast tissue present on the left side of the chest but otherwise her chest exam was normal. Cardiac and pulmonary exams were normal. Extremities were normal. There was one cafe-au-fait spot on the right elbow. On necrologic exam she was alert and active. She was very social. She is able to make some raspberry sounds but has no other words. She rolls over at will and nearly sits up on her own. Motor strength was apparently normal. Her tone was slightly increased at the ankles but otherwise tone appeared to be normal. Reflexes were 2+ and equal and toes were up-going to planter stimulation. Cranial nerve function seemed normal. MRI on 05/27/99 shows enlarged subarachnoid space frontally, and diffuse cortical dysplasia with irregular surface, shallow sulci, bilateral extended sylvian fissures and thick 5-10 mm cortex, but lacking obvious microgyri and microsulci. Other than this, it looks like typical PMG. This was clearly most severe in the posterior frontal, perisylvian and parietal regions with relative sparing of anterior frontal and occipital regions. The scan also showed mildly enlarged 3rd and lateral ventricles, and normal corpus callosum, brainstem and cerebellum. Chromosomes analysis was normal, 46 XX. A cranial CT scan for possible craniosynostosis was also normal. In summary, Shannon has macrocephaly, megalencephaly and an unusual cortical
dysplasia which looks most like PMG but with a few atypical features. Despite
this appearance, she appears remarkably spared in terms of development. This
also differs from the usual types of PMG, where such diffuse involvement
predicts much more severe developmental sequela. We considered a variant of
Sotos syndrome, but her facial appearance was not typical, also conferred on
review by Drs. Judith Allanson and Daniela Pilz, who were also present at the
meeting. We will keep her in mind as we see similar children in the future. /s/ William B. Dobyns, M.D. Gary D. Clark, M.D. cc: Mr. & Mrs. Higgins |
