Gen Aminolevulinic acid dehydratase (ALAD/G177) bersifat polimorfik dengan dua alel, ALAD1 dan ALAD2. ALAD2 mengikat timbal lebih kuat sehingga lebih rentan mengalami intoksikasi, salah satunya ditandai dengan gangguan sintesis heme dan anemia. Penelitian ini bertujuan mengidentifikasi polimorfisme gen ALAD, menganalisis kadar timbal darah dan faktor risiko lain yang mempengaruhi kadar timbal darah anak usia 1-5 tahun di wilayah eks daur ulang aki bekas Desa Cinangka, Kabupaten Bogor.  Studi potong lintang dilakukan pada September-Oktober 2019 melibatkan 128 anak. Darah diambil melalui ujung jari untuk beberapa pemeriksaan: polimorfisme gen ALAD menggunakan PCR Sequencing, kadar timbal darah mengunakan LeadCareTM Portable Analyzer, kadar Hb menggunakan HemoCue® Hb 201+ System, dan gangguan sintesis heme menggunakan mikroskop (perbesaran 1000x) pada slide hapusan darah yang diwarnai dengan pewarnaan Giemsa untuk mengidentifikasi basophilic stipping. Analisis bivariat menggunakan Chi Square dilakukan untuk melihat hubungan seluruh faktor risiko yang mempengaruhi kadar timbal darah. Analisis multivariat dilakukan untuk mengevaluasi variabel independen yang paling mempengaruhi kadar timbal darah.  Hasil penelitian menunjukkan distribusi frekuensi alel ALAD1 (0,95) dan ALAD2 (0.05) berada dalam keseimbangan Hardy-Weinberg. Alel ALAD2 ditemukan dalam dua bentuk (177C dan 177T). Sebanyak 69,5% anak memiliki kadar timbal darah tinggi (≥10 µg/dl). Anak dengan alel ALAD2 berisiko 5 kali lipat untuk memiliki kadar timbal darah tinggi, meskipun tidak signifikan secara statistik (OR=5,359, p=0,155). Anak dengan kadar timbal darah tinggi berisiko 1.017 kali untuk mengalami anemia (OR=1.017, p=1.000), berisiko 2 kali lipat untuk memiliki berat badan kurang (OR=2.031, p=0.231) dan mengalami gangguan sintesis heme yang ditandai temuan basophilic stippling dalam eritrosit (OR=1,991, p=0,214), meskipun tidak signifikan secara statistik. Jenis kelamin laki-laki menjadi faktor dominan tingginya kadar timbal darah, setelah dikontrol variabel polimorfisme gen ALAD, lama tinggal, penghasilan, jarak dan kelupas cat. Studi ini mengungkapkan pajanan timbal masih berlangsung di Desa Cinangka, diikuti gejala intoksikasi berupa anemia, berat badan kurang, dan temuan basophilic stippling. Studi dengan jumlah sampel yang lebih representatif diperlukan untuk mendapatkan hubungan yang lebih bermakna secara statistik. Kata kunci: polimorfisme gen ALAD, kadar timbal darah, daur ulang aki bekas, keracunan timbal

The Aminolevulinic acid dehydratase (ALAD/G177) gene is polymorphic with two alleles, ALAD1 and ALAD2. ALAD2 binds lead more strongly so that individual carriers are more susceptible to intoxication, one of which is characterized by impaired heme synthesis and anemia. This study aims to identify ALAD gene polymorphisms, analyze blood lead levels and other risk factors that affect blood lead levels in children aged 1-5 years in the former battery recycling area of Cinangka Village, Bogor Regency.  A Cross-sectional study was conducted in September-October 2019 involving 128 children. Blood was taken through fingertips for several examinations: ALAD gene polymorphism using PCR Sequencing, blood lead levels using the LeadCareTM Portable Analyzer, Hb levels using the HemoCue® Hb 201+ System, and impaired heme synthesis using a microscope (1000x magnification) on stained blood smear slides with Giemsa stain to identify basophilic stipping. Bivariate analysis using Chi-Square was conducted to see the relationship of all risk factors that affect blood lead levels. Multivariate analysis was performed to evaluate the independent variables that most influence blood lead levels.  The results showed that the frequency distribution of ALAD1 (0.95) and ALAD2 (0.05) alleles was in Hardy-Weinberg equilibrium. The ALAD2 allele was found in two forms (177C and 177T). A total of 69.5% of children had high blood lead levels (≥10 g/dl). Analysis of the relationship between the ALAD2 allele and blood lead levels showed that children carrying the ALAD2 allele had a 5-fold risk of having high blood lead levels, compared to children carrying the ALAD1 allele, although not statistically significant (OR=5.359, p=0.155). Children with high blood lead levels had a 1.017 times risk of developing anemia (OR=1.017, p=1,000), a 2-fold risk of being underweight (OR=2.031, p=0.231), and having impaired heme synthesis, which was characterized by basophilic stippling findings in erythrocytes (OR=1.991, p=0.214), although not statistically significant. Male became the dominant factor for high blood lead levels, after controlling for the ALAD gene polymorphism variables, length of stay, income, distance, and paint peeling. This study revealed that lead exposure was still ongoing in Cinangka Village, followed by symptoms of intoxication such as anemia, underweight, and findings of basophilic stippling. Studies with a more representative sample size are needed to obtain a more statistically significant relationship. Keywords:, ALAD gene polymorphism, blood lead level, ULAB recycling, lead toxicity