Clinical overlap between Trichorhinophalangeal and Floating Harbor Syndromes. J.W. Innis^1,2, J.L. Schuette¹, D.M. Martin¹. 1) Department of Pediatrics, The University of Michigan, Ann Arbor, MI; 2) Department of Human Genetics, The University of Michigan, Ann Arbor, MI.
   Trichorhinophalangeal (TRP) and Floating Harbor syndromes are multiple congenital anomaly syndromes with involvement of craniofacial and skeletal structures. Trichorhinophalangeal syndrome exists as three autosomal dominant forms (I, II, III) and one autosomal recessive form, with variable clinical features such as short stature, mild facial dysmorphisms, sparse hair, speech delay, and genitourinary abnormalities. Floating Harbor syndrome, also an autosomal dominant condition, was named after the two hospitals where it was originally identified and is characterized by short stature, expressive language delay, characteristic facies, and delayed bone age. TRP I is associated with mutations in TRPS1, a zinc finger transcription factor on 8q24. We report here a child with features that overlap significantly between TRP I and Floating Harbor syndromes. A.W. presented at age 2 months for evaluation of growth delay and multiple congenital anomalies. He was later found to have severe short stature, triangular face, short, light blonde hair, a prominent nose, protruding, low-set ears, a submucous cleft palate, ivory and cone epiphyses of the phalanges, Perthes disease of the left hip, and severely delayed expressive speech with normal speech reception abilities. Peripheral blood karyotype and FISH22q11deletion studies, endocrine evaluation (IGF-I, IGF-BP3) and hearing tests were normal. Family history revealed no similarly affected family members. Our patient's findings are more consistent with Floating Harbor syndrome; however, his features overlap significantly with TRP syndrome, emphasizing the importance of considering both diagnoses during evaluation of short stature, speech delay, and characteristic triangular facies. Molecular testing for TRPSI mutations is pending.