X-LINKED RECESSIVE PANHYPOPITUITARISM ASSOCIATED WITH A REGIONAL DUPLICATION IN XQ25-Q26

We present a linkage analysis and a clinical update on a previously re ported family with X-linked recessive panhypopituitarism, now in its f ourth generation. Affected members exhibit variable degrees of hypopit uitarism and mental retardation. The markers DXS737 and DXS1187 in the q25-q26 region of the X chromosome showed evidence for linkage with a peak LOD score (Z(max)) of 4.12 at zero recombination fraction (theta (max) = 0). An apparent extra copy of the marker DXS102, observed in t he region of the disease gene in affected males and heterozygous carri er females, suggests that a segment including this marker is duplicate d. The gene causing this disorder appears to code for a dosage-sensiti ve protein central to development of the pituitary.