Split hand/foot malformation (SHFM) is a group of congenital skeletal disorders which may occur either as an isolated abnormality or in syndromic forms with extra-limb manifestations. Chromosomal micro-duplication or micro-triplication involving 17p13.3 region has been described as the most common cause of split hand/foot malformation with long bone deficiency (SHFLD) in several different Caucasian and Asian populations. Gene dosage effect of the extra copies of BHLHA9 gene at this locus has been implicated in the pathogenesis of SHFLD.
The proband was a female child born to non-consanguineous parents. She was referred for genetic evaluation of bilateral asymmetric ectrodactyly involving both hands and right foot along with right tibial hemimelia. The right foot had fixed clubfoot deformity with only 2 toes. The mother had bilateral ectrodactyly involving both hands, but the rest of the upper limbs and both lower limbs were normal. Neither of them had any other congenital malformations or neurodevelopmental abnormalities. Genetic testing for rearrangement of BHLHA9 gene by quantitative polymerase chain reaction confirmed the duplication of the BHLHA9 gene in both the proband and the mother.
We report the first Sri Lankan family with genetic diagnosis of BHLHA9 duplication causing SHFLD. This report along with the previously reported cases corroborate the possible etiopathogenic role of BHLHA9 gene dosage imbalances in SHFM and SHFLD across different populations.

17p13.3 duplication is a rare and heterogeneous genetic syndrome. Microdeletions of this region are responsible for the symptoms of Miller-Dieker syndrome. We present a case of 17p13.3 duplication consisting of about 730kb in a patient with psychomotor developmental delay, concerning eye-hand coordination, posture, locomotion and speech. Among other symptoms, we found excessive physical development in relation to age, hypotonia, dysmorphic facial features (high and prominent forehead, low-set ears, hypertelorism, short nose, small upturned nose, narrow lips and pointed chin) and discrete changes in the CNS - enhanced frontal horns of the lateral ventricles and quite narrow corpus callosum. These symptoms overlap with phenotype of previously described patients with 17p13.3 duplication. The aberration has been identified by array comparative genomic hybridization (aCGH) and confirmed by fluorescence in situ hybridization (FISH). This publication presents a detailed, comparative characteristic of clinical fetures expression in discussed patient with 17p13.3 duplication and patients previously described in medical literature. Further cases with different variants of 17p13.3 duplication may contribute to characterise the specific genotypephenotype correlation.

Split hand/foot malformation (SHFM) with long-bone deficiency (SHFLD, MIM#119100) is a rare condition characterized by SHFM associated with long-bone malformation usually involving the tibia. Previous published data reported several unrelated patients with 17p13.3 duplication and SHFLD. Recently, the minimal critical region had been reduced, suggesting that BHLHA9 copy number gains are associated with this limb defect. Here, we report on 13 new families presenting with ectrodactyly and harboring a BHLHA9 duplication.