PMC8236592_01
Major clinical features of the patient. (A) Corneal leucoma in both eyes, with no visible pupils and a small left eyeball. (B) Nail dystrophy (right index finger). (C-E) Bilateral absence of the patella. (F) The full body photo of the patient.
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F1
She had smooth breathing, nasal fan three concave negative, no skin rashes, no swollen superficial lymph nodes, without cyanosis, smooth oral mucosa, red pharynx isthmus, no blisters or ulcers, thoracic and symmetrical on both sides, symmetrical double lung auscultation breath sounds, strong and rhythmic heart sound, no murmurs, no abdominal tenderness, no touching of the liver and spleen under the ribs, pitting edema of the hands, legs and feet, capillary refill time <3 s, and nail dystrophy (Figure 1). Lower limbs X-ray detected the bilateral absence of the patellas (Figure 1). An ultrasound examination of her urinary system showed enlargement of both kidneys, especially the left kidney (Supplementary Figure 1).
Genetic analysis. (A) Trio-based whole genome sequencing showing a heterozygous variation in the fifth exon of the LMX1B gene (805A>C [p.asn269his]) in the patient, but not her parents. (B) Patient pedigree. (C) Amino acid sequences of the LMX1B protein in different species, showing the variation was in the highly conserved homeodomain.
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F2
Echocardiography indicated a small amount of pericardial effusion (Supplementary Figure 2). This asparagine-to-histidine change was furthermore located in the HD domain, a region of the protein that is highly conserved among species and probably modulates DNA binding by the protein (Figure 2).