Subtopic Deep Dive

Hartnup Disorder and Neutral Amino Acid Transport
Research Guide

What is Hartnup Disorder and Neutral Amino Acid Transport?

Hartnup disorder is an autosomal recessive condition caused by mutations in SLC6A19 encoding the neutral amino acid transporter B0AT1, leading to impaired renal and intestinal reabsorption of neutral amino acids and pellagra-like symptoms.

SLC6A19 mutations disrupt transport of neutral amino acids like tryptophan in kidney and intestine. Key discoveries include independent reports by Kleta et al. (2004, 307 citations) and Seow et al. (2004, 274 citations) linking SLC6A19 to Hartnup. Bröer (2008, 924 citations) reviews epithelial transport physiology affected in the disorder.

Curated Papers

Key Challenges

Why It Matters

Hartnup research reveals mechanisms of neutral amino acid absorption, informing dietary therapies like tryptophan supplementation to prevent pellagra symptoms. Bröer (2008) details how transport defects cause plasma amino acid imbalances, guiding management of inherited disorders. Camargo et al. (2008, 292 citations) show ACE2 and collectrin interactions with B0AT1 mutations, aiding development of targeted therapies for renal transport defects.

Key Research Challenges

Genotype-Phenotype Correlations

Variable symptoms despite SLC6A19 mutations challenge prediction of disease severity. Kleta et al. (2004) and Seow et al. (2004) identified mutations but noted incomplete penetrance. Camargo et al. (2008) link specific mutations to altered collectrin interactions.

Transporter Partner Interactions

B0AT1 requires tissue-specific partners like ACE2 in intestine and collectrin in kidney. Camargo et al. (2008) demonstrate differential mutation effects on these partners. Danilczyk et al. (2006, 245 citations) confirm collectrin's essential role in renal transport.

Therapeutic Targeting

Dietary management inadequately addresses transport defects in severe cases. Bröer (2008) highlights systemic impacts of impaired absorption. Developing drugs to restore B0AT1 function remains unresolved.

Essential Papers

Amino Acid Transport Across Mammalian Intestinal and Renal Epithelia

Stefan Bröer · 2008 · Physiological Reviews · 924 citations

The transport of amino acids in kidney and intestine is critical for the supply of amino acids to all tissues and the homeostasis of plasma amino acid levels. This is illustrated by a number of inh...

The hexosamine biosynthetic pathway couples growth factor-induced glutamine uptake to glucose metabolism

Kathryn E. Wellen, Chao Lü, Anthony Mancuso et al. · 2010 · Genes & Development · 359 citations

Glucose and glutamine serve as the two primary carbon sources in proliferating cells, and uptake of both nutrients is directed by growth factor signaling. Although either glucose or glutamine can p...

Tryptophan Biochemistry: Structural, Nutritional, Metabolic, and Medical Aspects in Humans

Lionella Palego, Laura Betti, Alessandra Rossi et al. · 2016 · Journal of Amino Acids · 328 citations

L-Tryptophan is the unique protein amino acid (AA) bearing an indole ring: its biotransformation in living organisms contributes either to keeping this chemical group in cells and tissues or to bre...

Mutations in SLC6A19, encoding B0AT1, cause Hartnup disorder

Robert Kleta, Elisa Romeo, Zorica Ristic et al. · 2004 · Nature Genetics · 307 citations

Tissue-Specific Amino Acid Transporter Partners ACE2 and Collectrin Differentially Interact With Hartnup Mutations

Simone M. R. Camargo, Dustin Singer, Victoria Makrides et al. · 2008 · Gastroenterology · 292 citations

Hartnup disorder is caused by mutations in the gene encoding the neutral amino acid transporter SLC6A19

Heng Fong Seow, Stefan Bröer, Angelika Bröer et al. · 2004 · Nature Genetics · 274 citations

Cloning of the Sodium-dependent, Broad-scope, Neutral Amino Acid Transporter Bo from a Human Placental Choriocarcinoma Cell Line

Ramesh Kekuda, Puttur D. Prasad, You-Jun Fei et al. · 1996 · Journal of Biological Chemistry · 271 citations

We have isolated a cDNA from a human placental choriocarcinoma cell cDNA library which, when expressed in HeLa cells, induces a Na+-dependent amino acid transport system with preference for zwitter...

Reading Guide

Foundational Papers

Start with Bröer (2008, 924 citations) for epithelial transport overview, then Kleta et al. (2004) and Seow et al. (2004) for SLC6A19 discovery, followed by Camargo et al. (2008) for mutation effects.

Recent Advances

Camargo et al. (2008, 292 citations) on transporter partners; Danilczyk et al. (2006, 245 citations) on collectrin role; Palego et al. (2016, 328 citations) for tryptophan metabolism links.

Core Methods

Positional cloning (Kleta/Seow 2004), Xenopus oocyte expression for transport assays (Bröer 2008), mutagenesis studies of B0AT1-partner interactions (Camargo 2008).

How PapersFlow Helps You Research Hartnup Disorder and Neutral Amino Acid Transport

Discover & Search

Research Agent uses searchPapers('SLC6A19 Hartnup mutations') to find Kleta et al. (2004), then citationGraph reveals 307 forward citations including Camargo et al. (2008); exaSearch uncovers rare case reports on genotype-phenotype links.

Analyze & Verify

Analysis Agent runs readPaperContent on Bröer (2008) to extract transport kinetics data, then runPythonAnalysis with pandas to quantify citation overlaps across Hartnup papers; verifyResponse (CoVe) with GRADE grading scores mutation evidence as A-level from dual 2004 Nature Genetics reports.

Synthesize & Write

Synthesis Agent detects gaps in therapeutic targeting post-Bróer (2008), flags contradictions in mutation severity; Writing Agent applies latexEditText for reviewer-ready manuscripts, latexSyncCitations for 924 Bröer refs, and exportMermaid for B0AT1-ACE2 interaction diagrams.

Use Cases

"Analyze mutation impact on B0AT1 transport rates from Hartnup papers"

Analysis Agent → readPaperContent(Seow 2004 + Camargo 2008) → runPythonAnalysis(pandas plot of Km values) → matplotlib graph of neutral AA affinities.

"Draft review on SLC6A19 genotype-phenotype correlations"

Synthesis → gap detection → Writing Agent → latexEditText(structured sections) → latexSyncCitations(Kleta/Seow) → latexCompile(PDF with B0AT1 figure).

"Find code for modeling neutral amino acid transporter simulations"

Research Agent → searchPapers('SLC6A19 simulation model') → paperExtractUrls → paperFindGithubRepo → githubRepoInspect → exportPythonScript for kinetic modeling.

Automated Workflows

Deep Research workflow scans 50+ SLC6A19 papers via citationGraph from Kleta (2004), generates structured report on mutation spectra. DeepScan applies 7-step CoVe to verify Bröer (2008) transport models against Camargo (2008) experiments. Theorizer builds hypotheses on collectrin-B0AT1 rescue strategies from Danilczyk (2006).

Try Doxa for Hartnup Disorder and Neutral Amino Acid Transport Research

Frequently Asked Questions

What defines Hartnup disorder?

Autosomal recessive disorder from SLC6A19/B0AT1 mutations impairing neutral amino acid transport in kidney and intestine, causing pellagra-like rash, ataxia, and aminoaciduria.

What methods identified SLC6A19 as the Hartnup gene?

Positional cloning and functional expression studies; Kleta et al. (2004) and Seow et al. (2004) used linkage analysis and Xenopus oocyte assays to confirm B0AT1 transport loss.

What are key papers on Hartnup?

Kleta et al. (2004, 307 citations), Seow et al. (2004, 274 citations) for discovery; Bröer (2008, 924 citations) for physiology; Camargo et al. (2008, 292 citations) for mutation-partner interactions.

What open problems exist in Hartnup research?

Unclear genotype-phenotype correlations, limited therapies beyond diet, and incomplete understanding of B0AT1 activation by ACE2/collectrin in mutant forms.