No abstract

Acromesomelic dysplasias are skeletal disorders that disproportionately affect the middle and distal segments of the appendicular skeleton. We report genetic mapping studies in four families with acromesomelic dysplasia Maroteaux type (AMDM), an autosomal recessive osteochondrodysplasia. A peak LOD score of 5.1 at recombination fraction 0 was obtained with fully informative markers on human chromosome 9. In three of the four families, the affected offspring are products of consanguineous marriages; if it is assumed that these affected offspring are homozygous by descent for the region containing the AMDM locus, a 6.9-cM AMDM candidate interval can be defined by markers D9S1853 and D9S1874. The mapping of the AMDM locus to human chromosome 9 indicates that AMDM is genetically distinct from the two other mapped acromesomelic dysplasias, Hunter-Thompson type and Grebe type, which are caused by mutations in CDMP1 on human chromosome 20.

We report a 6 month old boy with congenital hydronephrosis, cleft palate, severe hypotonia, congenital heart defect, developmental delay, and characteristic facial features with an open mouthed appearance and full lower lip, who we believe is the third reported case of Okamoto syndrome. Okamoto syndrome is a recently described distinctive multiple congenital anomaly syndrome encompassing the above features for which an etiologic factor has not yet been identified. Our patient also had idiopathic splenomegaly and non-specific MRI changes in the brain, not reported in the first two cases.

Two siblings are presented displaying low Girth weight, marked microcephaly, severe mental and growth retardation, and convulsive disorder. Leukocyte and fibroblast cultures showed two cell lines, 46/47,+18, The extra E group chromosome in 30 to 40% of the cells was identified as No. 18 by Q‐banding and G‐banding techniques.